Optimal gating strategy for determining CD4+ recent thymic emigrants in human immunodeficiency virus-1 infected patients.

Abstract

Alterations of the frequencies of recent thymic emigrants (RTEs) in blood have been demonstrated to be associated with human immunodeficiency virus-1 (HIV-1) disease progression and immune reconstitution following antiretroviral therapy. Flow cytometry is a technology that offers many advantages over T-cell receptor excision circles (TRECs) quantification to determine the RTE subset in blood. However, the gating strategies for identifying RTEs by flow cytometry have not been evaluated and compared in much detail. In the present study, we compared the frequencies and the senescence levels of RTEs in 54 HIV-1 seronegative controls (HC) and 70 HIV-1 seropositive (HIV-1+) subjects using two different gating strategies by flow cytometry. Our analysis indicated that the CD4+ RTE population determined by the expressing pattern CD45RO-CD31+ contained the terminal effector memory T-cell population after HIV-1 infection, which could significantly affect the further phenotypic and functional studies. Our data demonstrate the necessity of including an additional marker such as CCR7 to distinguish better CD4+RTE subset in HIV-1+ subjects.