Expression of Activated Molecules on CD5⁺ b Cells in Autoimmune Hemolytic Anemia

Objective To detect the percentage of CD5⁺ B cells in peripheral blood (PB) of patients with autoimmune hemolytic anemia (AIHA) /Evans syndrome and the expression of active molecules on CD5⁺ B cells.

Methods The expressions of CD80, CD86, CD69 and HLA-DR on CD5⁺ B cells in PB of 25 cases with AIHA/Evans syndrome, (11 newly diagnosed, 14 remission) and 14 normal controls were detected by flow cytometry.

Results (1) The percentage and the quantity of CD19⁺ B cells in newly diagnosed patients were [(22.78±19.77)%, (34.47±22.88)×10⁷/L] respectively, which were obviously higher than those of remission patients [(6.80±5.47)%,(10.09±7.69)×10⁷/L] and normal controls [(7.76±2.6)%,(10.03±3.31)×10⁷/L](p<0.05), but there was no significant difference between the latter two groups. (2)The percentage of CD5⁺ B cells in B cells of untreated patients was [(27.44±18.43) %], which was higher than that of normal controls [(13.49±6.95) %, P=0.008]. The percentage of CD5^- B cells of untreated patients and normal controls were [(72.56±18.43) %], [(83.92±11.46) %] and there was no significant difference. (3)CD80 on CD5⁺ B cells of untreated patients was [(46.04±26.93)%], which was obviously higher than that of remission patients [(8.82±8.78)%,P=0.003] and normal controls [(6.27±4.87)%,P=0.002], the latter two groups had no significant difference. There was no significant difference of CD80 on CD5^- B cells among the three groups. CD86 on CD5⁺ B cells of untreated patients was [(37.37±24.18)%], which was significantly higher than that of remission patients [(16.53±10.31)%,P=0.004] and normal controls [(14.90±9.62)%,P=0.029], the latter two groups had no significant difference. But CD86 on CD5^- B cells are similar in the three groups and there was no difference. CD69 on CD5⁺ B cells of newly diagnosed patients was (median: 5.77%), which was higher than that of remission patients (3.34%) and normal controls(4.01%), but without any significant difference within three groups. CD69 on CD5^- B cells showed no significant difference among three groups. HLA-DR on CD5⁺ B cells and CD5^- B cells showed no significantly difference within three groups. (4)The expression of CD80[(46.04±26.93)%] and CD86[(37.37±24.18)%] on CD5⁺ B cells were higher than those on CD5^- B cells [(22.57±10.54)%,P=0.016], [(17.92±16.27)%,P=0.006]. The expression of CD69 (median: 5.77%) on CD5⁺ B cells was higher than that of on CD5^- B cells (median: 1.20%), but without significant difference. The expression of HLA-DR on CD5⁺ B cells and CD5^- B cells had no significant difference. (5)The expression of CD80 on CD5⁺ B cells [(8.82±8.78) %] was lower than that of on CD5^- B cells [(28.68±18.59) %, P=0.001]. The expression of CD86, CD69 and HLA-DR on CD5⁺ B cells and CD5^- B cells showed no significant difference. (6)The expression of CD80 on CD5⁺ B cells [(6.27±4.87)%] was lower than that of on CD5^- B cells [(27.54±9.42)%,P<0.05]. The expression of CD86ACD69 and HLA-DR on CD5⁺ B cells and CD5^- B cells had no significant difference.

Conclusions The percentage and quantity of B lymphocytes in PB of AIHA/Evans syndromes patients increased. CD5⁺ B lymphocytes are mainly cells and CD80 and CD86 on CD5⁺ B cells went up. The activated molecules on cell surface may be the basis of the different function of CD5⁺ and CD5^- B lymphocytes.