Abstract: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.