CD5⁺B Lymphocytes in the Bone Marrow of Immunic Hemocytopenia Patients and Its Clinical Significancy.

Background A subpopulation of B lymphocytes expressing CD5 antigen is involved in several autoimmune diseases through the release of autoantibodies. We investigate the quantitative of CD5⁺ B lymphocytes in the bone marrow of the patients with autoimmunic hemocytopenia and study the relationship between quantity of CD5⁺B cells and clinical or laboratorial parameters of these patients.Methods Quantities of CD5⁺B lymphocytes in the bone marrow(BM)of 14 patients with autoimmune hemolytic anemia(AIHA) or Evans syndrome, 22 immunorelated pancytopenia (IRP) patients and 10 normal controls were assayed by FACS. The correlation between their clinical or laboratory parameters and CD5⁺B lymphocytes was analyzed.

Results The qutantity of CD5⁺B lymphocytes of AIHA/Evans syndrome ((34.64±19.81)% or IRP((35.81±16.83)%) patients was significantly higher than that of normal controls((12.0±1.97)%)(p<0.05). There was no significant difference between those of AIHA/Evans syndrome and IRP patients(p>0.05). The quantity of CD5⁺B lymphocytes in the bone marrow of all cytopenic patients showed negative correlation with complement C₃(r=−0.416, p<0.05). In AIHA/Evans syndrome patients, the quantity of BM CD5⁺ B lymphocytes showed positive correlation with indirect bilirubin(IBIL) (r=1.00, p<0.05); In Evans syndrome patients, the quantity of CD5⁺B lymphocytes in their bone marrow showed positive correlation with PAIgG (r=0.761, p<0.05) and PAIgM(r=0.925, p<0.05). The qutantity of CD5⁺B lymphocytes in the bone marrow of all cytopenic patients showed negative correlation with treatment response (correlation coefficient tau-b=−0.289, p<0.05), but no relation with the yields of CFU-E, BFU-E,CFU-F and CFU-GM BM in vitro.

Conclusion BM CD5⁺B lymphocytes of the patients with autoimmunic hemocytopenias significantly increased and was related to the disease severity and clinical response. It was suggested that CD5⁺B lymphocytes might play an important role in the pathogenesis of autoimmunic hemocytopenia.