Alterations in Serum Interleukin-2 and Interleukin-10 Levels in Patients Infected with Entamoeba histolytica in Tikrit, Iraq

Background: The host immune response plays a pivotal role in the pathogenesis and outcome of amebic infections caused by Entamoeba histolytica. Cytokines such as interleukin-2 (IL-2) and interleukin-10 (IL-10) are key regulators of immunity, with IL-2 promoting cell-mediated responses and IL-10 suppressing inflammatory reactions. Understanding how E. histolytica infection influences these cytokine levels can provide insight into disease mechanisms and potential prognostic indicators. Objective: This study evaluated the serum levels of IL-2 and IL-10 in E. histolytica-infected patients compared to uninfected healthy individuals in Tikrit, Iraq. We aimed to determine if E. histolytica infection is associated with significant changes in these cytokines, and whether such changes vary with patient age. Methods: A case-control study was conducted involving 50 patients with confirmed E. histolytica infection (diagnosed via stool exam and PCR) and 20 healthy, uninfected controls matched for age and sex. Patients were stratified into four age groups (1–15, 16–30, 31–45, 46–60 years). Serum samples were collected and IL-2 and IL-10 concentrations were measured using enzyme-linked immunosorbent assay (ELISA) kits specific for human IL-2 and IL-10. Mean cytokine levels (±SD) in each group were compared, and ANOVA with post-hoc tests was used to assess statistical significance. Results: E. histolytica-infected individuals exhibited significantly elevated cytokine levels compared to controls. IL-10 was markedly increased in all infected age groups; the highest IL-10 levels were observed in young adults (16–30 years, mean 155.2 ± 9.3 pg/mL) and middle-aged adults (31–45 years, 135.2 ± 10.3 pg/mL) versus controls (70.1 ± 4.1 pg/mL, P≤0.01). IL-2 levels were also elevated in infected patients, particularly in the 16–30 group (102.2 ± 7.4 pg/mL) compared to controls (75.1 ± 5.1 pg/mL, P<0.01). Notably, in older infected patients (46–60 years), IL-2 levels (77.0 ± 5.5 pg/mL) were not significantly different from controls, suggesting an age-related decline in the IL-2 response. Overall, statistical analysis confirmed that both IL-10 and IL-2 concentrations differed significantly among the study groups (P≤0.01 for IL-10; P<0.05 for IL-2), with infected groups showing higher levels. Conclusions: E. histolytica infection is associated with heightened systemic levels of IL-10 and IL-2, reflecting activation of both anti-inflammatory and pro-inflammatory pathways. The pronounced increase in IL-10 suggests a strong regulatory (possibly parasite-driven) immune response during amebiasis, which may help limit tissue damage but could also facilitate parasite persistence. The IL-2 response, while elevated in most patients, was blunted in older individuals, potentially indicating age-related immune senescence. These findings improve our understanding of the immunological milieu in amebic infection and point to IL-10 and IL-2 as potential biomarkers for infection severity and host response, which might inform prognosis or therapeutic interventions in amebiasis.