糖皮质激素对慢性免疫性血小板减少症患儿树突状细胞的影响

目的：探讨树突状细胞（DCs）在儿童慢性免疫性血小板减少症（cITP）中的变化以及糖皮质激素对cITP患儿DCs的作用。方法：流式细胞术分别检测15例cITP患儿应用糖皮质激素治疗前后和20例对照者外周血DCs亚群的变化；体外培养并收集cITP患儿外周血单核细胞来源的DCs，采用流式细胞术检测其免疫表型。结果：与对照组比较，cITP患儿治疗前髓样DC（mDC）绝对数无明显改变，浆细胞样DC（pDC）绝对数降低，mDC/pDC比值增高（P<0.05）；cITP治疗后，pDC绝对数较治疗前增高，而mDC绝对数及mDC/pDC比值较治疗前降低（P<0.05）；cITP 患儿治疗前外周血DCs的HLA-DR、CD80、CD83和CD86 阳性表达率均明显高于对照组（均P<0.01）；治疗后cITP患儿DCs的HLA-DR、CD80、CD83和CD86表达率较治疗前均明显下降（P<0.01），与对照组比较差异无统计学意义（P>0.05）。结论：DCs亚群比例失衡及功能失调与儿童cITP的发病有关；糖皮质激素能增强cITP患儿 DCs的免疫抑制效应，可能是糖皮质激素有效治疗儿童cITP的机制。

Effect of glucocorticoid on dendritic cells in children with chronic immune thrombocytopenia

Objective To investigate the change in dendritic cells(DCs) in children with chronic immune thrombocytopenia(cITP) and the effect of glucocorticoid on DCs in children with cITP.Methods Fifteen children with cITP and 20 healthy controls were included in the study.Flow cytometry was used to measure the DC subsets count in the 15 children with cITP before and after glucocorticoid treatment as well as the corresponding values in the 20 healthy controls.The DCs derived from peripheral blood monocytes in children with cITP were cultured in vitro and collected,and their immunophenotypes were determined by flow cytometry.Results Before glucocorticoid treatment,the children with cITP showed no notable change in the absolute count of myeloid DCs(mDCs) but showed decreased absolute count of plasmacytoid DCs(pDCs) and increased mDC/pDC ratio compared with the healthy controls(P<0.05).After glucocorticoid treatment,the children with cITP demonstrated increased absolute count of pDCs and decreased absolute count of mDCs and mDC/pDC ratio compared with before treatment(P<0.05).Before glucocorticoid treatment,the children with cITP had significantly higher positive rates of HLA-DR,CD80,CD83 and CD86 on peripheral blood DCs than the healthy controls(P<0.01).All the positive rates were significantly decreased after glucocorticoid treatment(P<0.01),so that there was no significant difference from the healthy controls(P>0.05).Conclusions Disproportion and functional disturbance of DC subsets is associated with the pathogenesis of cITP in children.Glucocorticoid can strengthen the immunosuppression of DCs in children with cITP,which may contribute to the effectiveness of glucocorticoid as a treatment.