The study included 29 patients with locally advanced gastric adenocarcinoma who were enrolled in the Neo-PLANET trial at Zhongshan Hospital between 2018 and the present analysis. All participants underwent pre-operative [18F]FDG PET/CT imaging before starting a treatment regimen that combined immune checkpoint inhibitors with chemotherapy and radiation given before surgery. Using semiautomated image analysis, the team extracted a battery of metabolic parameters from the primary tumor, regional lymph nodes, and spleen, including maximum and mean standardized uptake values adjusted for lean body mass, metabolic tumor volume, and total lesion glycolysis. These measurements were then tested for associations with pathological response, disease-free survival, and overall survival.

What the researchers found was striking precisely because it was not where they expected it. The metabolic activity of the primary tumor itself, measured by SUVmax and SUVmean, did not reliably predict which patients would live longer. Nor did the metabolic activity of involved lymph nodes. Instead, it was the spleen, an organ that filters blood and houses large reservoirs of immune cells, that emerged as the most informative signal. Patients whose spleens showed higher mean standardized uptake values before treatment experienced significantly longer disease-free survival, with a hazard ratio of 0.19 and a 95 percent confidence interval of 0.037 to 0.94, and longer overall survival, with a hazard ratio of 0.12 and a 95 percent confidence interval of 0.016 to 0.83. Both associations reached statistical significance.

This finding ties into a growing body of evidence that the spleen plays an active role in the antitumor immune response, a concept the researchers refer to as the tumor-spleen immunity cycle. When immune checkpoint inhibitors unleash T cells to attack cancer cells, the spleen may act as a critical hub where activated immune cells are generated, expanded, and deployed. A metabolically active spleen on FDG PET may therefore reflect a heightened state of systemic immune activation, one that is already primed to respond when immunotherapy is administered. The researchers also found that higher S-SUVmean was linked to an increased combined positive score of PD-L1, a well-established biomarker that predicts response to immune checkpoint blockade, providing a biological bridge between the imaging finding and known immunology.

The study also examined whether pathological response, the traditional gold standard for judging neoadjuvant treatment efficacy, correlated with survival outcomes. Surprisingly, neither pathological complete response nor major pathological response was associated with disease-free survival or overall survival in this cohort of patients receiving immunotherapy plus chemoradiotherapy. This disconnect raises important questions about how treatment response should be assessed in the immunotherapy era, where the immune system may continue to exert antitumor effects long after visible tumor burden has been reduced, and where conventional pathological staging may not fully capture the depth of immune-mediated clearance.

Tumor size, however, did matter for one outcome. When researchers measured the length, width, and radius vector of the primary tumor on PET imaging, larger dimensions were significantly associated with shorter disease-free survival, with hazard ratios approaching 9 or higher and confidence intervals that excluded unity. Metabolic tumor volume, a three-dimensional measure of metabolically active tumor burden, also predicted shorter disease-free survival with a hazard ratio of 4.53. These parameters did not, however, reach significance for overall survival, suggesting that tumor bulk primarily influences the risk of recurrence rather than death from any cause.

When the researchers combined spleen metabolic activity with pathological response, the predictive power increased further. Patients who had either a higher S-SUVmean or achieved a major pathological response showed a dramatic survival advantage, with a hazard ratio of 0.09 for disease-free survival and 0.08 for overall survival, both statistically significant. This composite finding suggests that integrating imaging-based immune signatures with conventional pathological assessment could yield a more comprehensive picture of treatment efficacy than either measure alone.

The implications of this work extend beyond gastric cancer. Immune checkpoint inhibitors have transformed the treatment landscape for many solid tumors, yet only a subset of patients respond durably. Identifying reliable predictive biomarkers remains one of the most pressing challenges in oncology. While tumor PD-L1 expression, microsatellite instability, and tumor mutational burden are commonly used, they capture only part of the complex interplay between cancer and the immune system. A noninvasive imaging marker that reflects systemic immune activation, obtainable from a scan that patients already undergo for staging, would represent a practical and accessible addition to the biomarker toolkit.

The concept of the tumor-spleen immunity cycle is gaining traction among immunologists and oncologists alike. Animal studies have shown that splenectomy can impair the efficacy of immune checkpoint inhibitors in some models, and clinical observations have suggested that splenic metabolic changes on PET imaging correlate with response to immunotherapy in melanoma and lung cancer. This study is among the first to extend that framework to gastric cancer, a disease where immunotherapy is increasingly used in the perioperative setting but where predictive biomarkers remain poorly defined.

The authors caution that their analysis is based on a small number of patients from a single phase II trial and that the findings require validation in larger, independent cohorts. The confidence intervals, while statistically significant, are wide, reflecting the limited sample size. Nevertheless, the consistency of the spleen signal across both disease-free and overall survival, its biological plausibility, and its correlation with a known immunotherapy biomarker lend credibility to the result. If confirmed, S-SUVmean could become a simple, cost-effective tool for identifying patients most likely to benefit from neoadjuvant immunotherapy, helping clinicians personalize treatment decisions before a single dose is given and potentially sparing others from ineffective and toxic regimens.

Subject of Research: Predictive value of baseline FDG PET/CT spleen metabolic parameters for immunotherapy efficacy in locally advanced gastric adenocarcinoma

Article Title: Associations of baseline [18F]FDG PET/CT metabolic parameters with the efficacy of neoadjuvant immunotherapy plus concurrent chemoradiotherapy in patients with locally advanced gastric adenocarcinoma: a post hoc analysis of the Neo-PLANET phase II trial

Article References: Wang, J., Lv, J., Tang, Z., Wang, X., Wang, Q., Sun, Y., Shi, H., & Liu, T. (2026). Associations of baseline [18F]FDG PET/CT metabolic parameters with the efficacy of neoadjuvant immunotherapy plus concurrent chemoradiotherapy in patients with locally advanced gastric adenocarcinoma: a post hoc analysis of the Neo-PLANET phase II trial. BMC Medical Imaging. https://doi.org/10.1186/s12880-026-02751-z

Image Credits: AI Generated

DOI: 10.1186/s12880-026-02751-z

Keywords: FDG PET/CT, gastric adenocarcinoma, immunotherapy, spleen, biomarker, neoadjuvant chemoradiotherapy, disease-free survival, overall survival, PD-L1, tumor-spleen immunity cycle, Neo-PLANET trial, metabolic tumor volume

A team led by Franka Buytenhuijs, Cornelia Tune, Thomas C. Smits, Andrea Schampel, Lisa-Kristin Schierloh, René Pagel, Jürgen Westermann, and Johannes Textor set out to dissect how the T cell receptor repertoire is distributed across the major compartments of the mouse spleen. The spleen is an ideal testing ground for this question because it contains clearly demarcated regions: the T cell zones, where T cells normally congregate; the B cell zones, which are dominated by B lymphocytes but normally contain a small number of T cells; and the germinal centers, specialized structures within B cell zones where antibody affinity maturation takes place and where T helper cells provide critical support to B cells.

The researchers’ strategy relied on precision microdissection. Rather than analyzing whole spleens, they physically separated T cell zones, B cell zones, and germinal centers from both naïve mice and mice that had been immunized with a complex antigen. From each compartment they extracted DNA and sequenced the complementarity-determining region 3 of the T cell receptor beta chain, abbreviated CDR3β. This short stretch of amino acids is the most variable part of the receptor and serves as a practical fingerprint of clonal identity, allowing the team to track individual T cell clones and measure how abundant each clone was in each splenic neighborhood.

The initial comparison produced a striking result: the receptor repertoires of the three compartments looked substantially different from one another. At face value, this seemed to support the idea that receptor-intrinsic features guide T cell localization. But the team did not stop at the descriptive level. They built statistical models that asked a more demanding question: could the observed differences be explained without invoking any special homing properties of particular receptors, simply by accounting for how big each compartment is and how fast the cells within it are dividing?

The answer, in most cases, was yes. During the steady state, before any immune challenge, the handful of T cells found in B cell zones turned out to strongly resemble random subsets of the T cell zone repertoire. In other words, the T cells that stray into B cell territory appear to be an unbiased sample of the broader T cell population rather than a select subset with distinctive receptors. Once the effect of compartment size was factored into the analysis, the apparent compositional differences between T cell zones and B cell zones largely evaporated.

Immunization changed the picture in a dynamic and informative way. After the mice were challenged with antigen, expanded clones began to appear in the T cell zones by day three, marking the onset of the proliferative response. As the response progressed, these expanded clones later shifted their dominance toward the B cell zones, consistent with the migration of activated T helper cells to the sites where they assist B cells. Germinal centers harbored clones that had expanded even further, and these clones showed a tendency to group into clusters with high sequence similarity, reflecting the family relationships of proliferating T cells that had descended from common precursors.

To make sense of these temporal patterns, the researchers turned to a classical mathematical framework: the Galton-Watson branching process, a stochastic model of population growth in which each cell independently divides or fails to divide according to fixed probabilities. When they fitted this model of T cell proliferation to their data, it explained the repertoire differences observed during the immune response remarkably well. The implication is provocative: the central factor shaping the spatial differences in the splenic T cell receptor repertoire may simply be how much the cells in each compartment have proliferated, not any receptor-sequence-dependent trafficking rule.

The team also examined whether specific structural features of the receptor, beyond clonal identity, correlated with compartmental localization. Two features stood out initially: the length of the CDR3β region and the closeness of the receptor sequence to its germline configuration, a measure of how much the receptor has diverged from the inherited template. Both features showed more pronounced differences between compartments in the raw data, hinting that they might influence localization. Yet here again the models of random distribution and proliferation accounted for these differences almost entirely. Apparent sequence-based patterns dissolved once the confounding effects of compartment size and clonal expansion were explicitly modeled.

Taken together, the findings suggest that splenic T cell receptor repertoires are shaped predominantly by compartment size and proliferation rates rather than by T cell receptor sequence features. This conclusion carries practical consequences for the rapidly growing field of spatial immune profiling. As technologies for sequencing receptors from anatomically defined regions proliferate, researchers increasingly report spatial differences in repertoire composition and interpret them as evidence of receptor-guided positioning. This study demonstrates that such interpretations are unsafe without quantitative controls: a repertoire difference between two compartments can arise purely because one compartment is small, or because the cells within it have undergone more rounds of division, without any receptor-intrinsic homing behavior at all.

The authors argue that a quantitative assessment of T cell receptor repertoire dynamics across heterogeneous spatial compartments during an immune response is only possible when the effects of compartment size and proliferation are explicitly accounted for. Their work provides a template for how to do this, combining microdissection, high-throughput CDR3β sequencing, and mechanistic models of clonal expansion. For immunologists studying how the body marshals its T cell forces during infection or vaccination, the message is clear: before attributing spatial repertoire patterns to the sequences of the receptors themselves, one must first ask whether simple arithmetic of anatomy and cell division can explain the observation. In the mouse spleen, at least, it largely can.

Subject of Research: Spatial distribution of the splenic T cell receptor repertoire during immune responses in mice

Article Title: How compartmentalization and proliferation shape the splenic T cell repertoire during an immune response to a complex antigen in mice

Article References: Buytenhuijs, F., Tune, C., Smits, T. C., Schampel, A., Schierloh, L.-K., Pagel, R., Westermann, J., & Textor, J. (2026). How compartmentalization and proliferation shape the splenic T cell repertoire during an immune response to a complex antigen in mice. PLOS Computational Biology, 22(10), e1014859. https://doi.org/10.1371/journal.pcbi.1014859

Image Credits: AI Generated

DOI: 10.1371/journal.pcbi.1014859

Keywords: T cell receptor, repertoire sequencing, spleen, germinal centers, compartmentalization, clonal proliferation, Galton-Watson model, CDR3β, immunization, computational biology, spatial immunology, mouse model

The study, published in the journal Cell Death & Disease under the title “Temporal lymphatic tissue destruction and impairment of de novo T cell responses after an acute virus infection,” was led by Andreas Meyerhans, an ICREA research professor at Pompeu Fabra University. According to Meyerhans, there is a general perception that an acute viral infection is a relatively minor and transient event: once the virus is controlled and symptoms have resolved, the body is assumed to have fully recovered. He argues that this view may underestimate consequences that are not immediately visible and can persist long after the infection itself has resolved, a possibility that the new experimental data now support in concrete structural and functional terms.

The central finding concerns the spleen, a lymphoid organ that serves as a critical hub for filtering blood and orchestrating immune responses. As a collateral effect of the immune response generated to control and clear the virus, the researchers observed substantial disruption of the splenic architecture in mice that had recovered from acute infection. The tissue developed fibrosis, a process in which normal functional tissue is replaced by fibrous connective tissue, while the organization and localization of immune cells within the organ were markedly altered. These structural changes were not merely cosmetic; they impaired the cellular interactions required for the proper activation of T cells, the adaptive immune cells that recognize and eliminate infected cells throughout the body.

The functional consequences of this structural damage were measurable. After recovering from the acute phase of infection, the animals showed a prolonged impairment in their ability to mount new immune responses when exposed to subsequent challenges. In practical terms, the mice were left in an immunocompromised state, one that could not be detected simply by confirming that the virus was no longer present. Dr. Paula Cebollada Rica, first author of the study, emphasized this distinction, noting that the infection can be controlled without the host necessarily having fully recovered. She explained that the immune-related consequences of an acute viral infection can persist beyond the period in which the virus is detectable, leaving the animals vulnerable in ways that standard measures of recovery would miss.

This observation reframes the clinical significance of common acute infections. Illnesses often dismissed as minor and self-limiting, such as many respiratory or gastrointestinal viral infections, may carry hidden immunological costs that extend well beyond the symptomatic phase. The study does not establish that the same phenomenon occurs in humans, since the work was carried out in an experimental mouse model, but it provides a mechanistic proof of principle: the inflammatory and tissue-remodeling processes deployed to clear an acute virus can themselves inflict lasting damage on the lymphoid tissues that immune responses depend upon. Fibrosis of lymphoid tissue, once established, is generally difficult to reverse, which helps explain why the impairment the researchers documented was so persistent.

Having established that recovery from acute infection left the mice immunologically compromised, the research team turned to the obvious next question: whether anything could be done to prevent these long-term consequences. Vaccination was a natural candidate, because a vaccine exposes the immune system to a harmless form or fragment of a pathogen, allowing protective immunity to develop without the tissue damage associated with a full-blown infection. In the mouse model, this reasoning proved correct. Previously vaccinated animals that were subsequently infected showed none of the alterations observed in unvaccinated mice after recovery from acute infection. Their splenic architecture remained intact, and their T-cell functionality was comparable to that of naive animals that had never been infected at all.

Cebollada Rica summarized the significance of this result: vaccinated animals did not experience T-cell dysfunction or splenic alterations after recovering from an acute viral infection. This means, she explained, that vaccination not only prevented the disease resulting from the acute infection but also preserved the immune system’s ability to cope with new challenges. In other words, the vaccine’s protective effect operated on two levels simultaneously. It blunted the acute disease, and by doing so it prevented the collateral structural damage to lymphoid tissue that would otherwise have degraded immune function for an extended period afterward. The benefit of vaccination, in this framework, is not limited to avoiding a specific illness but extends to safeguarding the integrity of the immune system itself.

The findings arrive at a moment when vaccination policy is the subject of intense public and political debate. The researchers note that scientific evidence on the consequences of infections and the benefits of vaccination is particularly important at a time when political decisions can compromise collaborative disease prevention efforts. Their results suggest that the calculus used to evaluate vaccines may be incomplete if it considers only the prevention of acute disease. If acute infections leave behind lasting immunological impairment, as the mouse model indicates is possible, then each prevented infection also represents an avoided period of heightened vulnerability to other pathogens, reduced responsiveness to future vaccinations, and potentially diminished capacity to control emerging infections. These downstream effects are rarely captured in conventional assessments of vaccine value.

Meyerhans argued that the benefits of vaccination highlighted by this research matter not only for healthcare but also for how the value of vaccination is communicated to the public. He stressed that people should be aware of the broader protection that vaccination can provide and continue to trust vaccines as one of the most effective tools to prevent disease, adding that, put simply, vaccines provide strong health benefits at a relatively low cost to society. The study’s authors declared no competing interests, and the work was published as an experimental study in animals, with the article appearing in Cell Death & Disease on 10 September 2026.

For the field of infection biology, the study opens several lines of inquiry. The demonstration that an acute viral infection can trigger temporal lymphatic tissue destruction and impair de novo T cell responses provides a model system for dissecting how inflammation, fibrosis, and disrupted immune-cell localization translate into functional immunosuppression. It also raises questions about which viruses, which doses, and which host factors determine whether recovery is complete or leaves residual damage, and whether interventions beyond vaccination, such as anti-fibrotic or immunomodulatory treatments, could restore lymphoid architecture after infection. For now, the clearest message is preventive: in the mouse model, avoiding the acute infection altogether through vaccination preserved both the structure of the spleen and the functional competence of the T-cell compartment. The benefits of vaccination, the study concludes, extend beyond protection from infection to the protection of the immune system’s long-term capacity to respond to whatever comes next.

Subject of Research: Long-term immune impairment after acute viral infection and its prevention by vaccination in mice

Article Title: The benefits of vaccination extend beyond protection from infection

Article References: The benefits of vaccination extend beyond protection from infection. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: vaccination, acute viral infection, spleen, fibrosis, T cells, immune impairment, Pompeu Fabra University, Cell Death & Disease, mouse model, lymphoid tissue, immunology, public health

The research, conducted at the Department of Forensic Medicine in Hradec Králové in the Czech Republic, is the first systematic, statistically validated investigation of reactive splenic contraction in human hypothermia deaths. The finding itself is not new to physiology. The spleen acts as a rapidly mobilizable blood reservoir, capable of sequestering up to 200 to 250 milliliters of densely packed erythrocytes. When the sympathetic nervous system fires—during exercise, hypoxia, hemorrhage, or severe stress—the splenic capsule and vessels contract, squeezing stored red blood cells into the circulation and boosting oxygen-carrying capacity within moments. What had never been done before was to rigorously test whether this dramatic physiological response leaves a recognizable and diagnostically reliable footprint at autopsy in people who died of hypothermia.

The study team, led by Lenka Zátopková and Štěpánka Pohlová Kučerová together with senior author Petr Hejna, examined 54 fatalities attributed to accidental hypothermia and compared them against 170 randomly selected control cases representing both natural and non-natural deaths, including heart failure, cardiopulmonary failure, hanging, and suffocation. The researchers defined reactive splenic contraction by a strict macroscopic triad: an apparent reduction in splenic volume or weight relative to the decedent’s body size, wrinkling of the splenic capsule, and anemization of the red pulp on the cut surface, typically accompanied by increased firmness of the tissue. All three components had to be present simultaneously, a deliberately conservative requirement designed to maximize specificity and prevent misclassification based on isolated, nonspecific splenic changes.

The results were unambiguous. The complete contraction triad was identified in 48 of the 54 hypothermia fatalities, a prevalence of 88.9 percent, but in only 2 of the 170 controls, or 1.2 percent. This translates into a sensitivity of 88.9 percent and a specificity of 98.8 percent, with a positive predictive value of 96.0 percent, a negative predictive value of 96.6 percent, and an overall diagnostic accuracy of 96.4 percent. The statistical association between splenic contraction and fatal hypothermia was extraordinarily strong, with an odds ratio of 672.0 and a 95 percent confidence interval stretching from 131.4 to 3437.2, far beyond the threshold of statistical significance. Histological examination of the spleen in every hypothermia case confirmed the macroscopic impression of red-pulp anemization, revealing a depletion of erythrocytes within the red pulp and empty vascular lumina consistent with the wholesale mobilization of the splenic blood store.

Perhaps the most intriguing result concerns how splenic contraction relates to the established markers of hypothermia. Among the classical findings, only Wischnewsky spots showed a statistically significant association with splenic contraction. No significant relationships emerged with cold erythema, the inner knee sign, hemorrhages within core skeletal muscles, or fatty degeneration of renal tubular epithelial cells. In practical terms, this means that splenic contraction does not simply ride along with the other tissue changes of cold death. Among contraction-positive fatalities, cold erythema was absent in more than a quarter of cases, and roughly a third lacked either muscle hemorrhages or renal fatty degeneration; in six cases, both of those deeper findings were missing entirely. Splenic contraction, in other words, appears to carry independent diagnostic information rather than redundant confirmation of what other signs already show.

This independence points toward a compelling pathophysiological interpretation. Hemorrhagic and degenerative lesions such as muscle hemorrhages and renal tubular fatty change generally require prolonged survival and sustained exposure to critical cold before they develop. Splenic contraction, by contrast, reflects an immediate physiological adaptation: acute sympathetic activation, circulatory centralization shunting blood toward vital organs, and the rapid expulsion of the splenic erythrocyte reservoir into the systemic circulation. The authors therefore propose that a contracted spleen may represent one of the earliest morphofunctional responses to lethal cold stress, visible at autopsy even when the slower-developing hemorrhagic and degenerative manifestations have not yet had time to appear. Supporting this view, the mean splenic weight in contraction-positive hypothermia cases was just 76.1 grams, compared with 132.5 grams in contraction-negative hypothermia cases and 175.4 grams in controls, and the difference could not be explained by age differences between the groups.

The scientific groundwork for this conclusion was laid decades ago, though it was largely forgotten. In 1944, the German researcher Wendt demonstrated experimentally in rabbits that whole-body cooling reduced spleen volume by up to one third, with the most pronounced contraction occurring at core temperatures of 24 to 26 degrees Celsius, and that the organ regained its normal size after rewarming. Subsequent animal studies by Varman and Bernshtein corroborated the spleen’s reservoir role under hypothermic conditions, showing decreases in splenic weight and volume accompanied by rising circulating hemoglobin concentrations. Isolated human case reports followed, including Horn’s account of a 49-year-old sailor who died of cold exposure after falling overboard, and retrospective series by Gillner and Waltz and by Schneider and Klug that noted contracted spleens in a minority of hypothermia deaths. Two doctoral dissertations touched on the finding, but neither provided the prospective, controlled evidence needed to establish its diagnostic value, and major forensic textbooks continued to relegate splenic contraction to quotation marks and question marks—or to omit it entirely.

The practical implications for forensic practice are considerable. Hypothermia deaths are frequently misinterpreted at first glance, particularly when the scene suggests sudden natural death, acute intoxication, or even violence. Cold erythema and ecchymosis-like discolorations on the limbs can mimic traumatic injuries, occasionally raising suspicion of assault. In such ambiguous situations, the conditions that mimic hypothermia typically produce a congested, blood-filled spleen, whereas a contracted, pale, wrinkled spleen points decisively in the opposite direction. Because the contracted spleen is readily visible the moment the abdominal cavity is opened—sometimes alongside reverse Wischnewsky spots visible through the gastric wall—its early recognition can redirect the differential diagnosis toward hypothermia and prompt targeted dissection of the back and core musculature, inspection of the knee joints, and supplementary histological and toxicological analyses. The authors also suggest that the finding could support minimally invasive postmortem approaches, such as laparoscopic inspection of body cavities combined with postmortem imaging, where early visual cues carry exceptional value.

Modern imaging may soon extend this diagnostic reach even further. Preliminary work with postmortem computed tomography has reported elevated splenic radiodensity in hypothermia deaths, consistent with a denser, more compact parenchyma produced by contraction, and the present study’s exploratory imaging data showed compatible tendencies, though the small number of cases precluded statistical analysis and will be reported separately. The researchers are careful to emphasize the limits of their work: the study was conducted at a single institution, the macroscopic assessment was not blinded, interobserver agreement was not formally measured, and histological examination of the spleen was performed only in the hypothermia group. Splenic contraction is not pathognomonic and must never be interpreted in isolation. Nevertheless, with nearly nine out of ten hypothermia deaths showing the triad and fewer than two percent of controls doing so, the evidence strongly supports adding routine splenic assessment to the forensic autopsy protocol—transforming an organ long dismissed as morphologically unremarkable into a quiet but eloquent witness to death by cold.

Subject of Research: Validation of reactive splenic contraction as a diagnostic autopsy sign of fatal hypothermia

Article Title: Spleen contraction verified as a supportive autopsy sign of fatal hypothermia

Article References: Zátopková, L., Kučerová, Š. P., Kovařík, D., Pažinová, J., Pitková, R., Bačinová, P., Janík, M., & Hejna, P. (2026). Spleen contraction verified as a supportive autopsy sign of fatal hypothermia. International Journal of Legal Medicine. https://doi.org/10.1007/s00414-026-03984-x

Image Credits: AI Generated

DOI: 10.1007/s00414-026-03984-x

Keywords: hypothermia, forensic pathology, spleen, splenic contraction, autopsy, Wischnewsky spots, cold erythema, postmortem diagnosis, forensic medicine, blood reservoir, postmortem imaging, legal medicine

The team worked with male C57BL/6J mice, giving them purified CBD intraperitoneally at 0.2, 10 or 20 milligrams per kilogram of body weight. One group received the compound for just two days, representing short-term or sporadic use, while another group was treated daily for 28 days to mimic chronic exposure. Vehicle-treated controls received the same saline and Tween 80 solution without the active compound. The researchers then measured three classic pro-inflammatory cytokines in plasma, interleukin-1 beta, interleukin-6 and tumour necrosis factor alpha, using ELISA assays, and performed RNA sequencing on the liver and spleen to capture the full transcriptional response in each organ. Sequencing produced an average of 32.4 million raw reads per liver sample, with roughly three quarters of filtered reads uniquely mapped to the mouse reference genome GRCm39.

The cytokine results revealed a striking temporal split. After only two days of treatment, CBD significantly reduced IL-1β across all doses, with concentrations falling from about 69.7 picograms per millilitre in controls to between 49 and 57 picograms per millilitre, an 18 to 30 percent drop. TNF-α fell even harder, declining by roughly 20 to 45 percent in a dose-dependent fashion. IL-6, however, barely moved during this early window. Its decline emerged only during prolonged treatment: by day 14, IL-6 was significantly reduced at every dose, and by day 28 the two higher doses had driven levels down by approximately 40 to 45 percent, from 45.3 to under 29 picograms per millilitre. TNF-α remained suppressed at day 28 as well, suggesting that some anti-inflammatory effects persist while others fade or shift character over time.

The liver, the organ that also handles CBD clearance, turned out to be the epicentre of transcriptional change. Short-term high-dose treatment altered 526 genes, of which nearly 90 percent were upregulated, and enrichment analysis pointed squarely at mitochondrial energy metabolism: oxidative phosphorylation, electron transport chain activity, ATP synthesis and ribosome biogenesis were all prominently represented. The lowest short-term dose affected 116 genes linked to steroid and mineralocorticoid biosynthesis, tissue morphogenesis and lipid transport, while the intermediate dose touched only 11 genes, a reminder that cannabinoids often produce nonlinear, dose-dependent effects. After 28 days, the picture changed again. Long-term treatment altered between 104 and 404 genes depending on dose, with enrichment shifting toward fatty acid and eicosanoid metabolism, arachidonic acid pathways, and, at the highest dose, circadian rhythm regulation including the molecular clock gene Nr1d1, which encodes the nuclear receptor REV-ERBα.

That circadian finding may be one of the most intriguing threads in the study. REV-ERBα is a core component of the cellular clock, and previous work has shown it directly modulates innate immune responses and cytokine production. Immune function in general runs on a diurnal rhythm, with leukocyte trafficking and cytokine secretion varying robustly across the day. The fact that prolonged high-dose CBD enriched circadian and rhythmic process categories, while simultaneously downregulating genes involved in glucocorticoid receptor signalling and responses to nutritional and metabolic stimuli, suggests the compound may be tapping into the deep regulatory circuitry that connects clocks, stress hormones and metabolism rather than merely dampening inflammatory pathways one by one.

Perhaps the most counterintuitive result came at the highest long-term dose, where upregulated liver genes were enriched for innate immune and inflammatory processes, including antimicrobial humoral immunity, interleukin-1-mediated signaling and neutrophil chemotaxis. On its face, this looks like inflammation ramping up. Yet circulating cytokines remained reduced at the same time. The authors interpret this as evidence that transcriptional activation of immune-related pathways does not necessarily translate into systemic inflammatory output; it may instead reflect adaptive regulatory reprogramming. This distinction matters, because it separates genuine immunosuppression from a subtler recalibration of immune-metabolic networks, and it aligns with the well-established principle that cellular metabolism and immune cell behaviour are tightly intertwined.

The spleen told a very different story. Despite being the body’s central blood-filtering lymphoid organ, packed with T cells, B cells, macrophages and dendritic cells, and rich in CB2 cannabinoid receptors, the spleen showed remarkably modest transcriptional responses. Short-term treatment at the highest dose altered 40 genes, 38 of them downregulated, with the only significant enrichment involving lipid modification processes. Long-term treatment changed just two to four genes depending on dose. This muted splenic response, set against the liver’s dramatic remodeling, led the authors to a provocative conclusion: the systemic cytokine changes observed in blood are probably not driven primarily by classical immune organs, but rather by indirect regulation flowing from metabolically active tissues, with the liver acting as a kind of immunometabolic command centre.

Mechanistically, the findings fit CBD’s known multimodal pharmacology. Unlike THC, CBD has low affinity for the canonical CB1 and CB2 cannabinoid receptors and instead influences a scatter of molecular targets, including PPARγ, TRPV1 channels, adenosine signalling and redox-sensitive pathways, while inhibiting the transcription factor NF-κB, a master regulator of TNF-α and IL-1β expression. The early cytokine drops are consistent with NF-κB inhibition, while the delayed IL-6 decline may reflect a gradual attenuation of upstream inflammatory stimuli, since IL-6 production often sits downstream of IL-1β and TNF-α cascades. The lipid metabolism enrichment during long-term treatment echoes recent human cell studies showing that CBD can switch lipid mediator production toward inflammation-resolving species, and the authors’ own prior work found similar circadian and metabolic signatures in the kidneys of CBD-treated mice.

The study’s temporal dimension carries practical weight. Short-term exposure produced acute bioenergetic and stress-related transcriptional responses alongside rapid IL-1β and TNF-α suppression, whereas prolonged exposure shifted toward lipid handling, circadian regulation and broader immunometabolic pathways, with sustained IL-6 reduction. CBD’s high lipophilicity means it accumulates in lipid-rich, well-perfused tissues over repeated dosing, so the biological response evolves rather than simply intensifying. For anyone interpreting CBD experiments, or weighing its therapeutic potential, duration of exposure may matter as much as dose, and the two interact in ways that a single time point cannot capture.

The authors are careful about limitations. The pathways identified by RNA sequencing were not validated with targeted functional assays, bulk transcriptomics cannot distinguish changes within individual cell types from shifts in cellular composition, and only male mice were studied, leaving open the question of sex-dependent responses in endocannabinoid signalling and immunity. Still, the integrated picture is compelling: CBD lowered circulating pro-inflammatory cytokines while triggering strong, dose- and time-dependent transcriptional reprogramming in the liver and only limited changes in the spleen. Rather than acting as a blunt immunosuppressant, the compound appears to coordinate adjustments across mitochondrial bioenergetics, lipid metabolism, glucocorticoid pathways and circadian regulators such as REV-ERBα, nudging immune-metabolic networks toward balance. If that model holds up in functional studies and in both sexes, it could reshape how researchers think about CBD’s promise in inflammatory, autoimmune and metabolic disease.

Subject of Research: Effects of cannabidiol on systemic cytokines and liver and spleen transcriptomes in male mice

Article Title: Cannabidiol (CBD) differentially shapes systemic cytokines and transcriptomic profiles in the liver and spleen: insights from a male mouse model

Article References: Żurowski, J., Ocłoń, E., Jasielczuk, I., Szmatoła, T., Mizera-Szpilka, K., Semik-Gurgul, E., Sawicki, S., & Gurgul, A. (2026). Cannabidiol (CBD) differentially shapes systemic cytokines and transcriptomic profiles in the liver and spleen: insights from a male mouse model. Molecular Genetics and Genomics, 301(1), Article 200. https://doi.org/10.1007/s00438-026-02525-w

Image Credits: AI Generated

DOI: 10.1007/s00438-026-02525-w

Keywords: cannabidiol, CBD, cytokines, transcriptomics, liver, spleen, immunometabolism, NF-kappaB, circadian rhythm, REV-ERBalpha, mouse model, inflammation

Diabetes mellitus is far more than a disorder of blood sugar. Persistent hyperglycemia triggers a slow, systemic assault on tissues throughout the body, and while the kidneys, nerves, and retina receive most of the attention, the spleen quietly suffers as well. This fist-sized lymphoid organ orchestrates innate and adaptive immunity, filters aged red blood cells from circulation, and serves as a critical reservoir of immune cells. When the spleen falters, the consequences ripple outward: anemia worsens, infection susceptibility climbs, and the delicate balance between pro-inflammatory and anti-inflammatory signaling collapses. Earlier studies have documented splenic shrinkage, lymphoid degeneration, and immune dysregulation in diabetic animals, but effective pharmacological protectants remain scarce.

The research team, led by Asma B. Omer of Princess Nourah bint Abdulrahman University together with collaborators across Saudi Arabia, Oman, and India, chose streptozotocin, or STZ, as their diabetes-inducing agent. STZ is a glucosamine-nitrosourea compound that selectively destroys insulin-producing pancreatic beta cells, producing a model of persistent hyperglycemia that closely mirrors the metabolic and oxidative burden of uncontrolled human diabetes. A single intraperitoneal dose of 50 milligrams per kilogram was sufficient to push the Wistar rats into a diabetic state, setting the stage for eight weeks of treatment with oral rufigallol at two doses, 10 and 20 milligrams per kilogram per day.

The baseline damage inflicted by STZ was comprehensive and sobering. Diabetic animals developed sustained elevation of fasting blood glucose alongside a measurable reduction in spleen weight, signaling tissue atrophy. Their hematological profiles deteriorated in a pattern familiar to clinicians: anemia, elevated white cell counts consistent with chronic inflammatory activation, and falling platelet numbers. Beneath these visible changes, the molecular machinery of the spleen was under coordinated attack. Levels of malondialdehyde, a canonical marker of lipid peroxidation, surged, and nitric oxide production climbed, both signatures of unchecked oxidative assault on cellular membranes and proteins.

Equally telling was the collapse of the spleen’s antioxidant shield. Superoxide dismutase, catalase, and reduced glutathione, the enzymatic and non-enzymatic sentinels that normally neutralize reactive oxygen species, were all significantly depleted in the diabetic animals. With antioxidant defenses eroded, the pro-inflammatory cascade gained momentum. The researchers measured markedly increased concentrations of interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, and interferon-gamma, coupled with suppression of the anti-inflammatory cytokines interleukin-2 and interleukin-4. At the top of this inflammatory hierarchy sat nuclear factor kappa B, NF-κB, the transcription factor that coordinates the expression of dozens of inflammatory genes, and it was strongly activated in the diabetic spleen.

The third prong of the injury was apoptosis, the controlled self-destruction of cells. In the diabetic spleens, the pro-apoptotic protein Bax and the execution enzyme caspase-3 were upregulated, while the anti-apoptotic guardian Bcl-2 was diminished. This shift in the Bax-to-Bcl-2 ratio pushed splenic cells, including the lymphocytes and macrophages that populate the white and red pulp, toward self-elimination. Histopathological examination confirmed the functional data at the tissue level, revealing marked disruption of the normal splenic architecture, with damage to the lymphoid follicles and red pulp structures that underpin the organ’s immune and filtration roles.

Rufigallol treatment turned this grim molecular picture around in a dose-dependent fashion. The higher dose of 20 milligrams per kilogram consistently outperformed the lower dose across nearly every endpoint. Treated animals showed significantly reduced fasting blood glucose, recovered spleen weight, and improved hematological indices, including corrections in the anemia, leukocytosis, and thrombocytopenia that had accompanied the diabetic state. At the biochemical level, the compound restored the depleted antioxidant arsenal, elevating superoxide dismutase, catalase, and glutathione while simultaneously driving down malondialdehyde and nitric oxide, evidence that it both quenched existing oxidative damage and rebuilt the spleen’s capacity to resist it.

The anti-inflammatory and anti-apoptotic effects were equally striking. Rufigallol suppressed the elevated pro-inflammatory cytokines and restrained NF-κB activation, dampening the transcriptional engine of splenic inflammation. At the same time, it rebalanced the apoptotic threshold: Bax and caspase-3 expression fell while Bcl-2 rose, shifting cells away from self-destruction and toward survival. Microscopic analysis of the treated spleens confirmed that these molecular changes translated into tangible structural recovery, with substantially improved preservation of the lymphoid architecture compared with untreated diabetic controls. The authors conclude that rufigallol protected the spleen by simultaneously targeting oxidative stress, inflammatory signaling, and the apoptotic pathway, three interlocking mechanisms that converge on tissue survival.

The choice of rufigallol is scientifically grounded rather than arbitrary. The compound, formally 1,2,3,5,6-pentahydroxy-9,10-anthraquinone, belongs to the anthraquinone family, a class of polyphenolic plant metabolites with a growing resume in metabolic research. Related anthraquinones such as emodin, rhein, and aloe-emodin have shown anti-diabetic, antioxidant, and immunomodulatory properties in prior preclinical studies, and the hydroxyl-rich structure of rufigallol makes it a potent electron donor capable of neutralizing free radicals directly. The polyphenol’s redox activity, the researchers note, aligns with the broader recognition that dietary and plant-derived polyphenols can modulate redox signaling, bioenergetics, and cell fate decisions in ways that synthetic antioxidants often cannot.

The findings carry meaningful implications for a global diabetes epidemic that now affects hundreds of millions of people and continues to expand. Because splenic dysfunction compounds the immune weakness already characteristic of diabetes, contributing to heightened infection risk and poorer vaccine responses, protecting this organ could have clinical value beyond the laboratory. The authors caution that these results derive from a rodent model, and translation to human therapy will require pharmacokinetic profiling, toxicity evaluation, and ultimately controlled clinical trials. Nevertheless, the study adds rufigallol to the short list of natural compounds with demonstrated, mechanistically resolved protection of lymphoid tissue in diabetes, and it strengthens the case that inexpensive plant-derived anthraquinones deserve closer scrutiny as adjunctive agents against the multi-organ toll of chronic hyperglycemia. The research was supported by Princess Nourah bint Abdulrahman University Researchers Supporting Project number PNURSP2026R854.

Subject of Research: Protective effects of the anthraquinone compound rufigallol against streptozotocin-induced splenic injury in diabetic rats

Article Title: Rufigallol attenuates splenic damage caused by STZ by targeting oxidative stress, inflammation, and the apoptosis pathway

Article References: Omer, A. B., Afzal, M., Rafeeq, M., Murad, H. A. S., Alzarea, S. I., Sayyed, N., Kazmi, I., & Al-Abbasi, F. A. (2026). Rufigallol attenuates splenic damage caused by STZ by targeting oxidative stress, inflammation, and the apoptosis pathway. 3 Biotech, 16(10), Article 419. https://doi.org/10.1007/s13205-026-05047-9

Image Credits: AI Generated

DOI: 10.1007/s13205-026-05047-9

Keywords: rufigallol, diabetes, spleen, streptozotocin, oxidative stress, inflammation, apoptosis, NF-κB, anthraquinone, antioxidant, Bcl-2, caspase-3