目的：探讨下呼吸道感染呼吸道合胞病毒(RSV)患儿外周血辅助性T淋巴细胞(CD4)，原始T细胞(CD45RA+)，记忆性T细胞(CD45RO+)表达的变化。方法：用单克隆抗体免疫荧光标记，流式细胞仪检测30例RSV下呼吸道感染患儿急性期外周血单个核细胞(PBMCs)CD4+，CD45RA+细胞，其中11例同时检测CD45RO+细胞，同期检测9例年龄、性别无差异的健康儿为对照。结果：RSV下呼吸道感染组患儿CD4为(32.74±10.60)%，明显低于对照组(40.76±6.82)%，2组有显著性差异(P<0.05)。RSV下呼吸道感染组CD45RA+细胞为(80.65±10.35)%，比对照组(67.43±7.54)%明显升高，有显著性差异(P<0.01)。RSV下呼吸道感染组CD45RO+细胞比对照组降低，但无统计学意义(P>0.05)。结论：RSV感染急性期存在免疫功能紊乱，外周血CD4，CD45RO+下降，而CD45RA+明显增加，这可能是CD45RO+向呼吸道迁移的结果。

OBJECTIVE: To study the expression of CD4+ (helper T lymphocyte), CD45RA+ and CD45RO+ in PBMCs of infants with RSV LRTIs. METHODS: CD4+ and CD45RA+ were detected in 30 patients with RSV LRTIs and CD45RO+ in PBMCs was also assayed except for CD+4 and CD45RO+ in 11 of them with the flow cytometric analysis. Nine healthy children were used as the controls. RESULTS: In RSV infants, CD4+ cells ［(32.74±10.60)%］ decreased and CD45RA+ ［(80.65±10.35)%］ increased compared with the controls ［(40.76±6.82)% and (67.34±7.54)%, respectively］ (P<0.01). CD45RO+ cells also decreased, but not significantly. CONCLUSIONS: There is a disorder of immune function in PBMCs in infants with RSV.