Plasma interleukin-12 levels as a potential biomarker of fatigue and quality of life in patients with primary immune thrombocytopenia.

BACKGROUND

Fatigue significantly affects health-related quality of life (HRQoL) in patients with immune thrombocytopenia (ITP). However, the interplay between fatigue and 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 and 50 age-matched healthy controls. Fatigue and HRQoL were assessed using the Functional Assessment of the Chronic Illness Therapy (FACIT) scale. Concurrently, plasma levels of interleukin (IL)-2, IL-4, IL-6, IL-10, IL-12, IL-17, and interferon-gamma (IFN-γ) were measured via enzyme-linked immunosorbent assay (ELISA).

RESULTS

ITP patients had significantly lower total FACIT scores [median 146 (range 59-160]) and fatigue subscale scores [median 45 (range 9-52]) than controls [155 (149-159) and 49 (44-52), respectively; both p < 0.001]. IL-12 levels were significantly 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 patients with chronic ITP (> 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 immunological marker linked to this symptom burden.