Plasma Interleukin-12 Levels as a Potential Biomarker of Fatigue and Quality of Life in Primary Immune Thrombocytopenia

Background Fatigue significantly affects health-related quality of life (HRQoL) in patients with Immune Thrombocytopenia (ITP). The interplay of fatigue with cytokines in ITP remains poorly understood. Methods This study included 100 patients with persistent or chronic ITP who had not received ITP-directed therapy in the previous 8 weeks, along with 50 age-matched healthy controls. Fatigue and HRQoL were assessed using the Functional Assessment of Chronic Illness Therapy (FACIT) scale. Concurrently, plasma levels of IL-2, IL-4, IL-6, IL-10, IL-12, IL-17, and IFN-γ were measured via ELISA. Results ITP patients reported significantly lower total FACIT scores [median 146 (range 59–160)] and fatigue subscale scores [median 45 (range 9–52)] compared to controls [155 (149–159) and 49 (44–52), respectively; both p < 0.001]. IL-12 levels were markedly elevated in patients (313.2 vs. 95.5 pg/mL; p < 0.001) and showed a significant negative correlation with FACIT scores (Spearman’s ρ = − 0.272, p = 0.007). Multivariate analysis revealed that female sex, longer disease duration among chronic ITP patients (> 24 months), and elevated IL-12 levels were independently associated with greater fatigue and poorer HRQoL. Conclusions ITP is associated with significant fatigue and HRQoL impairment, with IL-12 emerging as a potential immunologic marker linked to this symptom burden.