CD5 + B lymphocytes secrete IL-10 rather than TGF-β1 which control the immune response in autoimmune haemolytic anaemia/Evans syndrome.

OBJECTIVE: To investigate the quantity and secretion function of cytokines-secreted CD5+ B lymphocytes in Autoimmune Haemolytic Anaemia (AIHA)/Evans syndrome (ES) patients.

METHODS: Twenty-five untreated AIHA/ES patients, 28 remission AIHA/ES patients and 25 healthy controls (HCs) were enrolled in this study. The quantity of CD5+ B lymphocytes which produce interleukin-10 (IL-10) (CD5+ IL-10+ ) and transforming growth factor (TGF-β1) (CD5+ TGF-β1+ ) were detected by flow cytometry (FCM). CD5+ B lymphocytes were sorted from peripheral blood (PB) by FCM and the expression of IL-10 and TGF-β1 mRNA in CD5+ B cells were measured by real-time PCR (RT-PCR).

RESULTS: The percentage of CD5+ IL-10+ B cells in CD5+ B lymphocytes in newly diagnosed patients was 82.18 ± 14.78%, which being significantly higher than that of remission AIHA/ES patients (56.68 ± 24.39%) and HCs (51.90 ± 22.95%) (p < .05). The percentage of CD5+ IL-10+ B cells in CD5+ B lymphocytes in newly diagnosed patients was negatively correlated with haemoglobin (Hb), complement 3 (C3) (p < .05) and positively correlated with lactate dehydrogenase (LDH), total bilirubin (TBIL) and indirect unconjugated bilirubin (IBIL) (p < .05). The expression level of IL-10 mRNA in CD5+ B lymphocytes of newly diagnosed patients (49.34 ± 22.84) was higher than that of remission patients (3.97 ± 3.83) and HCs (1.78 ± 1.66) (p < .05). There was no significant difference among three groups with the proportion of CD5+ TGF-β1+ B lymphocytes and the expression level of TGF-β1 mRNA in CD5+ B lymphocytes (p > .05).

CONCLUSIONS: CD5+ B lymphocytes could secrete IL-10 rather than TGF- β1 which control the immune response in AIHA/ES.