Inherited IL-10 Gene Pattern Flags Septic Shock Risk in ICU Patients

Sepsis is one of medicine’s most deceptive killers. Patients can appear stable on arrival at the intensive care unit, only to collapse into septic shock hours later—a state of refractory circulatory failure that kills between 30 and 50 percent of those who develop it. Clinicians have long lacked a reliable way to know, early on, which patients will spiral downward. Now a prospective study of 492 adults with sepsis suggests that part of the answer may be written in a patient’s DNA, in the form of two linked variants within the gene encoding interleukin-10, the body’s master anti-inflammatory signal.

The research, led by Amr A. Amin of Umm Al-Qura University in Makkah, Saudi Arabia, together with colleagues at Ain-Shams University in Cairo, focused on two single-nucleotide polymorphisms in the IL-10 gene on chromosome 1, designated rs1518111 and rs1554286. Rather than treating each variant in isolation, the team reconstructed how the two SNPs are inherited together as haplotypes and diplotypes—paired combinations of haplotypes on the two copies of chromosome 1. This multilocus approach matters because nearby variants that travel together, a phenomenon known as linkage disequilibrium, can obscure or exaggerate the apparent effect of any single variant when analyzed alone.

The study enrolled consecutive adults meeting the Sepsis-3 criteria in the intensive care units of a tertiary care medical center between August 2023 and September 2025. Blood and 24-hour urine samples were collected within 24 hours of sepsis confirmation, and genotyping was performed using TaqMan allelic discrimination assays with rigorous quality control: blinded laboratory staff, negative controls, and replicate testing of random sample subsets with complete concordance. Of the 492 patients, 84—about 17 percent—progressed to septic shock, defined as persistent hypotension requiring vasopressors to maintain a mean arterial pressure of at least 65 mmHg together with a serum lactate above 2 mmol/L despite adequate fluid resuscitation.

The genetic findings were striking. The two variants showed near-complete linkage disequilibrium, with a D′ of 1.00 and an r² of 0.903, meaning they are almost always inherited as a single block. When the researchers grouped patients by diplotype and adjusted for age, sex, admission white blood cell count, and baseline SOFA score, a clear pattern emerged. Patients homozygous for the variant T-A haplotype carried roughly 6.3-fold higher odds of progressing to septic shock compared with the heterozygous reference configuration, while those homozygous for the wild-type C-G haplotype showed dramatically lower odds—an adjusted odds ratio of 0.28, indicating a strongly protective profile. The allele frequency data underscore the disparity: among patients who developed shock, the minor allele frequency at both loci reached 0.785, compared with roughly 0.3 in patients whose sepsis remained hemodynamically stable.

Crucially, the genetic risk profile was not an abstract statistical construct—it tracked directly with measurable physiology. Homozygous variant carriers at either locus had the highest concentrations of IL-10 in both serum and urine, with median serum levels exceeding 214 pg/mL versus roughly 165 pg/mL in wild-type carriers, and they also exhibited significantly lower systolic and diastolic blood pressures. Heterozygous carriers, by contrast, resembled the wild-type group on both counts, a pattern consistent with a recessive mode of inheritance. Septic shock patients overall showed elevated serum IL-10 (median 193.9 pg/mL versus 169.4 pg/mL) and urinary IL-10 (20.8 versus 17.2 pg/mL) compared with non-shock patients, suggesting a coordinated counter-regulatory immune response spanning both systemic and renal compartments.

The biology behind this pattern is complex and, at first glance, paradoxical. Interleukin-10 is essential for reining in the inflammatory cascade during infection, preventing the collateral tissue destruction caused by unchecked cytokine amplification. But excessive or prolonged IL-10 expression can push patients into immunoparalysis—a state of immune suppression that may heighten susceptibility to secondary infections and mortality. The new findings hint that inherited variation within the IL-10 locus may tilt patients toward one end of this immunological spectrum, predisposing some individuals to an exaggerated anti-inflammatory response that coincides with hemodynamic deterioration. The authors are careful to note that the association between genotype, cytokine levels, and low blood pressure does not establish causation; the cross-sectional cytokine measurements cannot determine whether elevated IL-10 preceded, accompanied, or resulted from the onset of shock.

The team also explored whether these biomarkers could discriminate which patients would deteriorate. Serum IL-10 alone performed best among individual markers, achieving an area under the receiver operating characteristic curve of 0.851; at a threshold of 210 pg/mL it detected 95.2 percent of septic shock cases with 69.6 percent specificity and a negative predictive value of 98.6 percent. A combined clinical-genetic model integrating serum IL-10, admission white blood cell count, and diplotype category pushed the AUC to 0.889 (95 percent confidence interval, 0.820–0.958), with the same high sensitivity and 72.5 percent specificity. Urinary IL-10 and white blood cell count alone were more modest, with AUCs of 0.736 and 0.744 respectively.

Important caveats temper the enthusiasm. The performance estimates were derived and evaluated within the same cohort, without bootstrap correction, cross-validation, or external validation, so they likely represent an optimistic ceiling. The study was also single-center, and allele frequencies and linkage disequilibrium patterns can vary substantially across ancestries—a particular concern given that Middle Eastern populations remain underrepresented in genomic reference resources, a gap the authors cite as motivation for their work. IL-10 was measured at only a single early time point, precluding analysis of cytokine trajectories, and the panel did not include other established inflammatory and perfusion markers such as IL-6, procalcitonin, monocyte HLA-DR, or serial lactate. The authors also observed deviations from Hardy–Weinberg equilibrium within the non-shock reference group, which they interpreted cautiously given that disease-associated cohorts frequently deviate from HWE because of risk-allele enrichment.

Notably, this is not the first time rs1518111 has surfaced in the team’s work. An earlier study, conducted in a completely independent cohort recruited between 2016 and 2018, linked the same variant and paired serum and urinary IL-10 measurements to sepsis-associated acute kidney injury. The recurrence of rs1518111 across two clinically distinct severe-sepsis phenotypes strengthens the rationale for continued investigation, even though the two outcomes are not interchangeable and cannot be assumed to share a common causal pathway.

For now, the message is one of promise rather than prescription. The authors explicitly caution that IL-10 genotyping should not yet be used to guide vasopressor selection or any bedside treatment decisions, and they emphasize that their combined model is hypothesis-generating pending validation in larger, multicenter, multi-ethnic cohorts with serial biomarker measurements and functional studies of the implicated variants. If those efforts succeed, the vision is compelling: a rapid genetic and biochemical fingerprint, obtainable within the first day of ICU admission, that flags which sepsis patients carry the highest risk of circulatory collapse—turning septic shock from a sudden catastrophe into a foreseeable event that clinicians can anticipate, monitor, and perhaps preempt.

Subject of Research: Association of IL-10 gene haplotypes and diplotypes with septic shock susceptibility, cytokine expression, and hemodynamic dysfunction in critically ill patients

Article Title: IL-10 diplotype and septic shock: Genotype–Phenotype associations with hemodynamic dysfunction and IL-10 expression

Article References: Amin, A. A., Althubiti, M., Fatani, S. H., Mufti, A. H., Azher, Z. A., Malibari, G. M., & Bogari, N. M. (2026). IL-10 diplotype and septic shock: Genotype–Phenotype associations with hemodynamic dysfunction and IL-10 expression. Frontiers in Molecular Biosciences, 13, Article 1958117. https://doi.org/10.3389/fmolb.2026.1958117

Image Credits: AI Generated

DOI: 10.3389/fmolb.2026.1958117

Keywords: sepsis, septic shock, interleukin-10, IL-10 gene polymorphisms, haplotype, diplotype, linkage disequilibrium, genetic association study, biomarkers, hemodynamic dysfunction, cytokine expression, critical care