慢性特发性血小板减少性紫癜患者外周血来源树突细胞分泌B细胞活化因子研究

目的 探讨慢性特发性血小板减少性紫癜(ITP)患者外周血单个核细胞来源树突细胞(MoDC)分泌的B细胞活化因子(BAFF)特点,以及MoDC对B细胞增殖的作用,了解ITP的发病机制.方法 动态研究10例慢性ITP患者,ELISA法检测ITP患者治疗前及治疗有效后血清及MoDC经脂多糖活化后的培养上清中BAFF的水平,荧光实时定量PCR测定活化后MoDC BAFF mRNA的表达;MoDC培养上清与B淋巴细胞共培养5 d,流式细胞术检测CFSE荧光强度及3H-胸苷(3.7×104Bq/孔)掺入测定B细胞增殖.结果 ITP患者治疗前血清及MoDC培养上清BAFF水平为(2461±483)ng/L和(1113±113)ng/L,MoDC的BAFF mRNA相对表达水平为1.70±0.23,均明显高于治疗后[(621±53)ng/L、(490±49)ng/L和0.34±0.12]及对照组[(742±77)ng/L、(582±63)ng/L和0.52±0.08];ITP患者血清及MoDC培养上清BAFF水平、MoDC的BAFF mRNA表达水平之间呈正相关,而与血小板计数之间均呈负相关;CFSE荧光标记及3H-胸苷掺入测定显示与治疗后及对照组比较,ITP患者治疗前MoDC培养上清明显促进B细胞增殖,治疗后与对照组比较差异无统计学意义.结论 BAFF与慢性ITP病情变化有密切关系,慢性ITP患者MoDC可能通过分泌BAFF直接促进B细胞增殖,为不依赖于T细胞的直接作用.这可能在慢性ITP的抗体产生中起着一定作用.

The role of B cell-activating factor secreted by peripheral blood monocyte-derived dendritic cell in chronic idiopathic thrombocytopenic purpura

Objective To explore the characteristics of B cell-activating factor(BAFF) secreted by peripheral blood monocyte-derived dendritic cell (MoDC) in chronic idiopathic thrombocytopenic purpura (cITP) and the function of MoDC on B cell proliferation. Methods Ten cITP patients were studied dynamically before and after treatment. The BAFF levels in serum and the supernatant of LPS stimulated MoDC were tested with ELISA. The BAFF gene expression in LPS stimulated MoDC was tested with RQ-PCR, the B cell proliferation co-cultured with the superuatant of LPS stimulated MoDC for 5 days was tested with flow cytometry for CFSE and 3H thymidine incorporation. Results The BAFF level in serum(serum BAFF) [(2461 ±483) ng/L], and supernatant of LPS stimulated MoDC ( supernatant BAFF) [( 1113 ± 113 ) ng/L] and BAFF mRNA in LPS stimulated MoDC ( BAFF mRNA) ( 1.70 ± 0. 23 ) before treatment were higher than that after treatment [(621±53) ng/L,(490±49) ng/L and 0.37±0.12] and normal group [(742±77) ng/L,(582 ± 63 ) ng/L and 0.52 ± 0. 08]. There was a positive correlation among serum BAFF, supernatant BAFF and BAFF mRNA, and a negative correlation among serum BAFF, supernatant BAFF and BAFF mRNA and blood platelet count (BPC) in all ITP patients. The supernatant of LPS-stimulated MoDC from untreated patients enhanced B cell proliferation as compared with the supernatant of LPS-stimulated MoDC from treated patients and normal group. Conclusion BAFF might contribute to disease development in cITP. MoDC may directly increase B cell proliferation by secreting BAFF without T cell help, playing an important role in the antibody production in cITP.