Effects of arsenic trioxide plus thalidomide on immune function in patients with myelodysplastic syndrome

Objective To investigate the effects of arsenic trioxide plus thalidomide on immune function of patients with myelodysplastic syndrome (MDS).Methods Fifty-seven MDS patients (Low risk,medium risk and high risk) and 30 healthy volunteers were selected as our subjects.Thirty-four cases with medium risk Ⅱ and high risk MDS patients were randomly divided into A and B groups.Seventeen MDS patients in A group were treated with arsenic trioxide plus thalidomide,and 17 MDS patients in B group were treated with low-dose cytarabine.Lymphocyte subsets in peripheral blood were examined by flow cytometry (FCM).The adverse effect of arsenic trioxide and thalidomide were recorded.Results Compared with control group,the number of T lymphocytes(CD3 +),B lymphocytes (CD3-CD19 +) and NK cell (CD3-(CD16 CD56) +) of patients with MDS were significantly lower,and the differences were statistically significant (t =2.157,2.349,2.958 ; P ＜ 0.05 or P ＜ 0.01).The helper CD3 + CD4 + T cell (Th) ratio decreased in MDS patients than that of control group (t =2.412,P ＜ 0.05).The inhibition CD3 + CD8 + T cells (Ts) ratio increased (t =2.749,P ＜ 0.01).Th/Ts ratio inversion was seen in MDS patients.As the progression of MDS increase,Ts cell expression gradually increased and NK cells ratio gradually decreased.However,there was no significant difference among three groups.Th cells and B lymphocytes in the risk group were lower than that in the low risk group,and the difference was statistically significant (F =4.896 and 4.516,P ＜0.05),but there was no significant difference in the terms of the number of T lymphocytes,Th cell,ratio of Th/Ts and B lymphocytes among MDS groups.Number of T lymphocytes,B lymphocytes and NK cell count in group A after treatment were increased than that before treatment (t =2.435,2.468,2.653,P ＜ 0.05).In group A,2 cases were complete remission,4 cases with partial remission,and 5 cases with hematologic improvement.The total effective rate was 64.71％ (11/17),and curative effect is obviously better than that of B group (x2 =4.253,P ＜ 0.05).Meanwhile adverse effect was mild.Conclusion The cellular and humoral immune function decreased in MDS patients.The treatment of arsenic trioxide plus thalidomide on MDS is proved safety and efficacy,which might work by improving immune function of MDS patients. Key words: Arsenic trioxide;  Thalidomide;  Myelodysplastic syndrome;  Flow cytometry; Immune function