Abstract: Objective To investigate the role of CD40L in the production of autoantibody and immune complex-mediated tissue damage. Methods The expression of CD40L on PBMC in patients with active or remission SLE was examined by flowcytometry. Results The CD40L expression in pateints with active SLE increased significantly before and after the stimulation of anti-CD3 mAb in comparison with normal controls. However, the CD40L expression in patients with remission SLE was normal before the stimulation and increased significantly after the stimulation of anti CD3 mAb. Conclusion There is a defect of the CD40-CD40L pathway in SLE.

Key words: Lupus erythematosus, systemic, CD40L