Figure 1 Effects of 56 sera from SSc patients (solid symbols) and 30 sera from healthy controls (HCs) (open symbols) on ROS generation and cell proliferation. (A) Production of hydrogen peroxide (H₂O₂) and (B) Production of nitric oxide (NO) by human umbilical venous endothelial cells (HUVECs), NIH 3T3 fibroblasts and HEp‐2 cells. (C) Cell proliferation determined by [³H]thymidine incorporation. (D) Primary normal human fibroblast proliferation. Error bars represent SEM. *Denotes statistical significance.