The commentary addresses the study proposing SMPDL3B as a novel biomarker for ME. Biomarkers are measurable indicators, often found in blood or tissue, that signify the presence or progression of disease. The authors critically assess the methodology employed in the initial research that presents SMPDL3B as a promising candidate. Central to their examination is the validation process of biomarkers, which is often fraught with complexity. In the context of ME, where subjective symptoms predominately contribute to the diagnosis, establishing robust, objective biomarkers is paramount. This commentary emphasizes the importance of rigor in the validation process to ensure that any suggested biomarker can reliably signify the presence and severity of the disease.

One critical aspect discussed is the various means of assessing biomarker efficacy. In the context of SMPDL3B, Chen and Yan argue that current studies may not adequately cover the necessary breadth of patient characteristics and symptomatology. Validating a biomarker like SMPDL3B requires comprehensive longitudinal studies that capture the variability inherent in clinical presentations of ME. This is especially pertinent since ME patients often display a heterogeneous range of symptoms, complicating the process of establishing a one-size-fits-all biomarker approach. Robust studies should also incorporate diverse patient cohorts to enhance the generalizability of findings.

In addition, the commentary highlights the necessity of addressing laboratory protocols surrounding supraphysiological drug concentrations when considering therapeutic interventions aimed at biomarkers. When designing treatments that utilize drugs targeting biomarkers such as SMPDL3B, it is vital to ascertain the biochemical environment in which these interactions occur. High concentrations of drugs can lead to off-target effects, potentially exacerbating symptoms or introducing new health risks. The authors press for a more nuanced understanding of pharmacokinetics specific to ME, emphasizing that this understanding could influence how therapeutically relevant a biomarker might be.

Furthermore, the authors explore the implications of using SMPDL3B as a focal point for both clinical assessment and therapeutic interventions. Investigating a biomarker’s role extends beyond its identification; it encompasses understanding how it interacts within pathological pathways and its influence on disease progression. As Chen and Yan illustrate, targeting SMPDL3B within treatment regimens might offer transformative options for individuals living with ME. However, such approaches hinge on deciphering the precise functions and regulatory mechanisms surrounding SMPDL3B’s activity in biological systems.

Critically, the authors urge the scientific community to remain vigilant regarding the ethics of biomarker research. The race to establish definitive biomarkers can lead to premature conclusions and potentially misguided treatment approaches. Ethical considerations regarding patient participation in research, informed consent, and equitable access to emerging therapies must be front and center as the field progresses. Moreover, the authors advocate for transparency in communication with patients, ensuring they understand the implications of targeting specific biomarkers in their treatment plans.

As researchers expand their understanding of biomarkers in ME, the potential for personalized medicine becomes increasingly apparent. Personalized medicine strives to tailor treatment strategies to the individual characteristics of each patient, guided by specific biomarkers. Such an approach has the potential to revolutionize how clinicians understand and manage ME, as well as improve patient quality of life. Highlighting the therapeutic promise of targeting SMPDL3B, the commentary engages with the broader future of treatment avenues for ME, fostering hopes for tailored interventions that resonate with patients’ unique experiences.

Moreover, the dialogue initiated by Chen and Yan urges scholars and practitioners alike to consider the broader systems biology context in which SMPDL3B operates. The interconnections between various biomarkers, immune responses, and metabolic pathways should not be overlooked. This intricate web necessitates an interdisciplinary approach, melding insights from molecular biology, clinical medicine, and pharmacology to accurately delineate treatment parameters anchored in individual biomarker responses.

Discussion surrounding SMPDL3B showcases the intersection between theoretical research and real-world applicability. The journey from a novel biomarker to established therapeutic target is often laden with detours, failures, and breakthroughs. As such, ongoing collaborations among researchers, clinicians, and patient advocacy groups can prove beneficial. Initiatives fostering engagement can enhance understanding of patient experiences and symptoms, providing researchers with invaluable context and insight into the potential efficacy of novel biomarkers and treatment approaches.

In conclusion, the commentary by Chen and Yan lays the groundwork for ongoing discourse around the role of SMPDL3B as a potential biomarker and therapeutic target in myalgic encephalomyelitis. By underscoring the critical importance of validating biomarkers within a robust ethical framework, the authors highlight the complexities inherent in the quest for effective diagnostics and treatments for ME. As this field progresses, the interplay of rigorous scientific inquiry, patient-centric approaches, and an emphasis on collaborative efforts will be instrumental in paving the way for innovative solutions that address the myriad challenges posed by this debilitating condition.

The exploration of biomarkers like SMPDL3B encourages optimism for future research endeavors, emphasizing that the journey to understanding and treating ME is far from over. Continued vigilance, ethical considerations, and comprehensive, inclusive studies are essential as we navigate this intricate landscape with the ultimate goal of improving lives affected by myalgic encephalomyelitis.

Subject of Research: Myalgic Encephalomyelitis and Biomarkers

Article Title: Comment on “SMPDL3B as a novel biomarker and therapeutic target in myalgic encephalomyelitis” critical considerations on biomarker validation and Supraphysiological drug concentrations

Article References: Chen, J., Yan, L. Comment on “SMPDL3B as a novel biomarker and therapeutic target in myalgic encephalomyelitis” critical considerations on biomarker validation and Supraphysiological drug concentrations. J Transl Med 23, 1327 (2025). https://doi.org/10.1186/s12967-025-07121-x

Image Credits: AI Generated

DOI: https://doi.org/10.1186/s12967-025-07121-x

Keywords: Biomarkers, Myalgic Encephalomyelitis, SMPDL3B, Therapeutic Targets, Validation, Pharmacokinetics.

ME/CFS remains one of the most enigmatic chronic illnesses, characterized by profound fatigue, post-exertional malaise, cognitive dysfunction, and a host of other diverse symptoms that drastically impair normal functioning. Historically, some factions in the medical community have attributed the condition primarily to deconditioning—a decline in physical fitness resulting from inactivity—and altered patient effort, implying psychological rather than biological origins. The authors confront these notions head-on, presenting rigorous analysis and evidence that underscore the complexity of ME/CFS as more than mere physical inactivity or lack of motivation.

Central to this reply is the assertion that the pathophysiology of ME/CFS cannot be distilled into simplistic explanations rooted in altered patient effort or deconditioning effects. The authors articulate that the energy production and utilization abnormalities documented in ME/CFS go well beyond what could be accounted for by reduced physical activity alone. This includes evidence from metabolomics studies revealing systemic metabolic insufficiencies and mitochondrial dysfunction—a biochemical anomaly pointing to compromised cellular energy generation integral to symptom manifestation.

Moreover, Walitt and colleagues emphasize the nuanced role of neuroinflammation in ME/CFS. Increasingly sophisticated neuroimaging techniques, such as PET scans detecting glial activation, have revealed ongoing inflammation in specific brain regions involved in fatigue, cognition, and autonomic regulation. Such neuroimmune dysregulation offers a tangible, biologically plausible mechanism that sharply contradicts the notion of mere volitional deconditioning or lack of effort.

The intensity and persistence of post-exertional malaise—the hallmark symptom of ME/CFS distinguished by profound and prolonged exacerbation of symptoms after minimal physical or cognitive exertion—stands as further evidence defying the altered effort hypothesis. Patients experience measurable neuroimmune and autonomic system perturbations following exertion, refuting the idea that symptoms could be solely attributable to behavioral factors. The authors meticulously detail these pathophysiological responses observed in clinical and biological assessments after exertional challenges, highlighting the stark divergence from normal fatigue.

Another crucial point in this reply involves differentiating ME/CFS from primary psychiatric disorders such as depression or somatization. While overlapping symptoms may exist, the biological markers, immune profiles, and autonomic disturbances in ME/CFS delineate a distinct disease entity. The reply draws on emerging data from longitudinal cohort studies that track immune molecule fluctuations, neuroanatomical changes, and autonomic nervous system irregularities, underscoring the organic basis of the syndrome and invalidating reductive psychological explanations.

The authors also critique the methodology of prior studies that have dismissed altered effort and deconditioning. They suggest that many of these investigations suffer from small sample sizes, lack of rigorous controls, and failure to account for the heterogeneity of ME/CFS phenotypes. Such methodological shortcomings have contributed to misinterpretations and perpetuated stigmatizing beliefs about patient effort. The reply advocates for more robust, multidisciplinary research frameworks capable of capturing the multifaceted nature of ME/CFS.

In addition, the reply highlights the pressing need for novel biomarkers to objectively assess disease status and progression in ME/CFS. Currently, diagnosis relies heavily on clinical criteria and patient reports, which, while invaluable, demand complement by quantifiable biological indicators. Walitt and colleagues discuss promising avenues, including metabolomic signatures, cytokine profiles, and neuroimaging markers that collectively offer a path toward disentangling physiological abnormalities from behavioral overlays.

Importantly, the authors engage with the broader implications of these scientific insights for clinical practice. Dismissing ME/CFS symptoms as mere reflections of altered effort risks undermining patient care, delaying accurate diagnosis, and limiting access to appropriate therapies. Recognizing the biological basis mandates holistic treatment strategies incorporating immunomodulation, mitochondrial support, and tailored rehabilitative interventions sensitive to post-exertional malaise, rather than solely focusing on behavioral reconditioning.

The reply also acknowledges the heterogeneity within ME/CFS populations, urging personalized medicine approaches to account for variations in symptomatology, underlying pathophysiology, and comorbidities. Such personalized interventions would be better positioned to address unique patient needs and maximize therapeutic responsiveness, moving beyond one-size-fits-all mental models that have historically hampered treatment outcomes and increased patient frustration.

Walitt and colleagues underscore that advancing ME/CFS research demands interdisciplinary collaboration spanning immunology, neurology, metabolism, psychology, and rehabilitation sciences. Only through an integrative lens can the multifactorial nature of ME/CFS be fully appreciated and effectively managed. They call for enhanced funding, larger patient cohorts, and application of cutting-edge technologies to unravel the cascade of molecular and systemic dysregulation that underpins symptom development.

Public understanding and awareness also emerge as critical targets in the authors’ reply. Persistent misconceptions around effort and deconditioning have not only influenced physician perspectives but also shaped public and policy narratives, often stigmatizing patients and impeding support. By communicating the scientific realities of ME/CFS in accessible terms, the medical community can foster empathy, reduce stigma, and promote better resource allocation toward this historically neglected disease.

The reply concludes with a strong reaffirmation that ME/CFS is fundamentally a complex, biologically-based illness with far-reaching systemic effects, not simply a consequence of psychological maladaptation or physical inactivity. The authors emphasize that improving patient outcomes requires acknowledging these biological truths and dismantling outdated, simplistic explanatory frameworks.

This comprehensive response represents a crucial step forward in refining the medical dialogue surrounding ME/CFS. It refocuses attention on scientific rigor, patient-centered understanding, and the urgent need for objective biomarkers and effective therapeutics. As new evidence continues to accumulate, the hope is that this will pave the way toward better diagnostic clarity, compassionate care, and ultimately meaningful improvements in quality of life for those afflicted by this devastating condition.

In the context of a global health landscape increasingly recognizing the importance of post-viral syndromes and chronic neuroimmune disorders, this reply serves as a timely reminder that dismissive approaches grounded in misconceptions about patient effort and deconditioning do a great disservice to both science and humanity. The evolution of ME/CFS research exemplifies the power of perseverance and open-mindedness in confronting medical enigmas that have long eluded definitive explanation.

Overviewing the implications, it becomes clear that this exchange marks an essential turning point—not only clarifying scientific misconceptions but also galvanizing momentum for a new era of targeted research and holistic clinical management for ME/CFS. It inspires hope that with continued commitment and innovation, the decades-old mysteries enshrouding this condition will finally begin to unravel, bringing relief to millions worldwide.

As ME/CFS advocacy groups, clinicians, and researchers rally behind this evidence-based perspective, the path forward must be navigated with both scientific integrity and human compassion. The reply by Walitt and colleagues effectively dispels myths of altered effort and deconditioning and illuminates a future where ME/CFS is fully recognized as a distinct biological illness requiring dedicated resources, empathetic care, and an unwavering commitment to discovery.

Subject of Research: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) pathophysiology and the validity of hypotheses related to altered effort and deconditioning.

Article Title: Reply to: Altered effort and deconditioning are not valid explanations of myalgic encephalomyelitis/chronic fatigue syndrome.

Article References:
Walitt, B., Chin, L., Drinkard, B. et al. Reply to: Altered effort and deconditioning are not valid explanations of myalgic encephalomyelitis/chronic fatigue syndrome. Nat Commun 16, 9177 (2025). https://doi.org/10.1038/s41467-025-64539-z

Image Credits: AI Generated

ME/CFS, characterized by profound fatigue, cognitive dysfunction, post-exertional malaise, and multi-systemic symptoms, has long challenged clinicians due to the absence of reliable diagnostic tests. The disease’s clinical overlap with other disorders renders symptom-based diagnosis problematic. Addressing this diagnostic void, the Cornell team has developed computational models capable of discerning disease-specific cfRNA patterns, essentially reading the molecular “activity logs” cells leave behind as they undergo damage or death. By capturing these cellular footprints, the study brings the prospect of a minimally invasive blood-based assay closer to reality.

The research, recently published on August 11, 2025, in the prestigious Proceedings of the National Academy of Sciences, details how plasma samples from ME/CFS patients and sedentary healthy controls were analyzed to isolate and sequence extracellular RNA fragments. These fragments serve as proxies for gene expression profiles from diverse tissues impacted by the disease. Utilizing advanced machine-learning classifiers, the team identified over 700 transcripts significantly divergent between ME/CFS cases and controls, facilitating a molecular signature indicative of the syndrome.

Leading the study, Anne Gardella, a doctoral candidate specializing in biochemistry, molecular, and cell biology at Cornell University, highlighted the unique capability of this method to shed light on systemic cellular alterations. “The circulating cfRNA reflects a composite snapshot of cellular turnover and stress responses occurring throughout the body,” Gardella explained. “This allows us to map disease-associated molecular changes across multiple organ systems simultaneously, which is crucial given ME/CFS’s widespread physiological impacts.”

The project was conceived through a collaboration between the De Vlaminck Lab, under associate professor Iwijn De Vlaminck, renowned for pioneering cell-free nucleic acid technologies, and Dr. Maureen Hanson’s team, leaders in ME/CFS pathophysiology research. De Vlaminck’s laboratory previously demonstrated the diagnostic power of cfRNA in identifying Kawasaki disease and multisystem inflammatory syndrome in children (MIS-C), signaling the versatility of this approach in inflammatory and immune-mediated conditions.

This interdisciplinary effort leveraged deep computational analysis, applying machine-learning algorithms adept at handling high-dimensional data to uncover patterns invisible to conventional statistical methods. These computational models not only confirmed immune dysregulation known to occur in ME/CFS but also implicated extracellular matrix disorganization and T cell exhaustion, signaling broad immune dysfunction and tissue remodeling abnormalities. Such insights provide a more nuanced biological framework for understanding ME/CFS beyond symptomatology.

Crucially, the team employed deconvolution techniques informed by cell type-specific gene expression markers, drawn from prior single-cell RNA sequencing data, to pinpoint the cellular origins of the cfRNA. This revealed six distinct cell types with differential RNA signatures in ME/CFS patients, with plasmacytoid dendritic cells—the primary producers of type I interferons—showing the most significant elevation. This finding suggests an aberrant antiviral immune activation state underpinning the disease’s chronicity.

Monocytes, platelets, and various T cell subsets also displayed altered cfRNA levels, reinforcing the hypothesis of systemic immune dysregulation. These immune perturbations may contribute to the constellation of symptoms experienced by patients, from neuroinflammation to vascular dysfunction. The data also hint at persistent immune activation or unresolved viral triggers, potentially connecting to the hypothesis of post-infectious etiologies for ME/CFS.

The cfRNA-based classifier developed achieved an accuracy rate of 77% in distinguishing ME/CFS patients from controls—a promising but preliminary figure. While this degree of precision is insufficient to constitute a standalone diagnostic tool today, it represents a significant leap forward given the historical diagnostic ambiguity surrounding ME/CFS. Improvements with larger cohorts and integration with other biomarkers could enhance diagnostic performance, ultimately aiding clinicians in making objective, timely diagnoses.

Beyond diagnostics, the technology offers a potent research instrument to dissect the multifaceted biology of ME/CFS and related chronic illnesses such as long COVID. Notably, while long COVID has recently amplified awareness of post-infectious chronic syndromes, ME/CFS remains more prevalent and, in many cases, more severely disabling. The Cornell team’s innovation could therefore serve as a reference model for studying infection-associated chronic diseases with overlapping symptomatology but distinct molecular fingerprints.

The study benefits from strong support by the National Institutes of Health and the WE&ME Foundation, underscoring the growing prioritization of ME/CFS research funding. The research’s translational potential is considerable, potentially catalyzing the development of future blood-based assays to monitor disease activity and therapeutic response, thereby personalizing patient care amidst a historically neglected field.

This research is a testament to the power of integrating molecular biology, computational science, and clinical insight to address one of medicine’s most confounding syndromes. With further validation and technological refinement, circulating cfRNA analysis stands to revolutionize not only ME/CFS diagnosis but also our understanding of chronic, systemic illnesses long shrouded in mystery, marking a new frontier in precision diagnostics.

Subject of Research: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and circulating cell-free RNA biomarkers

Article Title: Circulating cell-free RNA signatures for the characterization and diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome

News Publication Date: 11-Aug-2025

Web References:

• DOI: 10.1073/pnas.2507345122

Keywords: Chronic fatigue syndrome, diseases and disorders, health and medicine