Analysis of Circulating B-1 B Lymphocyte Subsets in Patients with Systemic Lupus Erythematosus

Objectives : To define the abnormalities in homeostasis of B-1 B lymphocytes compartments in human SLE. Methods : Peripheral blood was obtained from 7 patients with untreated active SLE patients and same patients at the time of inactive disease after immunosuppressive therapy. The frequencies of CD5(+)CD45RA(int) B-la B lymphocyte, CD5(+)CD45RA(low) B-lb B lymphocyte, and CD5-CD45RA(high) conventional B-2 B lymphocyte subsets were analyzed. For the control group, peripheral blood from 7 healthy adults and 7 patients with infectious fever were utilized. Results : B-la B lymphocyte subset was found at high frequency in active SLE patients compared to the fever control (33.5 +/- 15.0% vs 20.1 +/- 5.3%, p 0.01). In contrast, B-2 B lymphocyte subset was found at lower frequency compared to the fever control (65.6 +/- 15.1% vs 77.9 +/- 5.6%, p=0.04). No difference in frequency of B-lb B lymphocyte subsets was found between active SLE and the control. After immunosuppressive theray, B-la B lymphocyte subset was markedly decreased with increase in B-2 B lymphocyte subset (p=0.05). Conclusion : These results indicate that there are abnormalities in B cell compartments with expansion of B-la B lymphocyte subset and contraction of B-2 B lymphocyte subset associated with the disease activity in patients with SLE.