Reduced expression of transforming growth factor-β1 and correlated elevation of interleukin-17 and interferon-γ in pediatric patients with chronic primary immune thrombocytopenia (ITP).

Background: Dysregulated T helper (Th) cells are considered important in the pathophysiology of chronic primary immune thrombocytopenia (ITP). The present study investigated whether levels of Th cytokines in pediatric patients with chronic ITP were different compared with healthy controls.

Procedures: Fifty-seven pediatric patients with chronic ITP and 28 healthy controls were enrolled. Patients were divided into three groups based on their platelet counts at the time of the study: (i) active disease <50 × 10(9) /l (n = 23), (ii) stable disease 50-150 × 10(9) /l (n = 23), and (iii) in remission >150 × 10(9) /l (n = 11). Plasma concentration of Th1 [interferon gamma (INF-γ), interleukin 2 (IL-2)], Th2 (IL-4, IL-10), Th3 [transforming growth factor-β1 (TGF-β1)], and Th17 (IL-17) cytokines were investigated by enzyme-linked immunosorbent assay.

Results: IFN-γ was increased in patients with active (P < 0.001) and stable disease (P = 0.026) when compared with controls. The IL-17 level was significantly higher in all of the 3 patient groups. In addition, there was a positive correlation between IL-17 and IFN-γ levels in chronic ITP patients (r = 0.640, P < 0.001). Reduced TGF-β1 expression was observed in patients with active (P < 0.001) and stable disease (P = 0.001) in comparison with controls. Moreover, TGF-β1 level in patients was positively correlated with the platelet count (r = 0.355, P = 0.007).

Conclusions: Elevation of IL-17 and IFN-γ may be an important dysregulation of cellular immunity in pediatric patients with chronic ITP. The disease activity is associated with reduced production of TGF-β1.