Lowered IL-4-producing T cells and decreased IL-4 secretion in peripheral blood from subjects with juvenile rheumatoid arthritis

Abstract

Background: To evaluate T helper 1 (Th1)/Th2 cells and cytokines in patients with three different subtypes of juvenile rheumatoid arthritis (JRA).

Methods: Peripheral blood was obtained from 25 children with JRA suffering from active arthritis (8 systemic, 9 pauciarticular and 8 polyarticular). Eight healthy children were recruited as controls. T helper cells from peripheral blood mononuclear cells (PBMC) were evaluated by using intracellular staining analysis of cytokine production with 3-colored flow cytometry. A Th1 cell was defined as an interferon-gamma (IFN-gamma) producing CD4+ cell, and a Th2 cell as an interleukin-4 (IL-4) producing CD4+ cell. The production of IL-2, IL-4, IL-5 and IFN-gamma from PBMC was measured by ELISA.

Results: In comparison with normal controls, the patients with JRA had significantly fewer Th2 cells among their PBMC (0.78 +/- 0.56% vs. 5.44 +/- 2.33%, p < 0.001). The percentage of Th1 cells among PBMC was not different between patients and normal controls (4.32 +/- 3.24% vs. 4.52 +/- 2.56%, p > 0.5). The ratio of Th1/Th2 cells in the patient group was significantly higher than the control group (8.38 +/- 8.63 vs. 0.95 +/- 0.66, p < 0.001). After 24-hour culture, the PBMC from JRA patients produced less IL-4 than that of controls (3.61 +/- 0.56 pg/mL vs. 4.29 +/- 0.68 pg/mL, p = 0.002). The production of IL-2, IL-5, and IFN-gamma did not show significant differences between JRA patients and normal controls.

Conclusion: Decreased IL-4 producing T-helper cells were identified in all three subtypes of JRA. This implicates that an imbalance of Th sub-populations might be a predominant factor in JRA pathogenesis.