Transient T cell receptor β-chain variable region-specific expansions of CD4+ and CD8+ T cells during the early phase of pediatric human immunodeficiency virus infection:: Characterization of expanded cell populations by T cell receptor phenotyping

T cell receptor (TCR) repertoire perturbations ape commonly detected in CD8(+) T cells during adult primary human immunodeficiency virus (HIV) infection and have been associated with HN-specific cytotoxic T cell responses, By use of flow cytometry, transient high-level TCR beta-chain variable region-specific expansions of CD4(+) and CD8(+) T cells were observed more frequently in HIV-infected children than in children exposed to HIV who remained uninfected. TCR beta-chain diversity analysis and diversity-specific polymerase chain reaction were used to study the clonality of expanded CD4(+) and CD8(+) subsets. In CD8(+) T cells, structural features of the complement-determining regions 3 were altered during the course of the expansion, and persistent TCR clonotypes were observed, consistent with antigen-driven selection. In contrast, TCR beta-chain variable region-specific expansions without clonotypic overrepresentation or persistence were observed in CD4(+) T cells, possibly related to HIV-specific helper T cell responses or to the progressive destruction of the CD4(+) cell compartment.