IL4 and systemic sclerosis: To verify whether soluble mediators were involved in ROS generation in T lymphocytes, we treated SSc and normal T cells with IL-1 (10 ng/ml), IL-4 (15 ng/ml), IL-6 (5 ng/ml), IL-13 (50 ng/ml), IFNα (0.5 ng/ml), TNFα (1 ng/ml), TGFβ (1 ng/ml), and PDGF-BB (15 ng/ml) for 15 minutes before ROS analysis.