Expression of CD40 on Peripheral Blood Lymphocytes of Patients with Systemic Lupus Erythematosus

Peripheral blood mononuclear cells (PBMC) of patients with SLE and health controls were isolated by gradient centrifugation of heparinized blood, and the expression of CD40 on B lymphocytes from both patients and controls were detected by flow cytometry analysis. The correlation between expression of CD40 and serum anti-dsDNA antibody level were analysed,so did expression of CD40 and SLE activity index (SLEDAI). It was found that the ratio of B lymphocytes in PBMC and the ratio of positive CD40 in B lymphocytes were higher in patients with active SLE than those in patients with inactive SLE and controls. The mean fluorescence intensity (MFI) of CD40 were highest in patients with active SLE and lowest in controls. In patients with active SLE,there were high degree positive correlation between the ratio of positive CD40,MFI and anti-dsDNA antibody,SLEDAI. In patients with inactive SLE,there were positive correlation between MFI and SLEDAI. These results suggest that expression of CD40 on peripheral blood B lymphocytes of patients with SLE were increased and it's level were associated with disease activities.