Proportions of circulating follicular helper T cells are reduced and correlate with memory B cells in HIV-infected children

IntroductionHIV causes defects in memory B cells in children, but the mechanisms of those defects have not been fully elucidated. One possible mechanism is the lack of T-cell help to B cells during immune reactions. However, few studies have assessed the effect of HIV on follicular helper T cells (TFH cells) in children.MethodsIn this study, follicular-homing CD4 T cells and memory B cells were assessed in HIV-infected children and compared with children from the community. CXCR5 and CD45RO were used as markers of follicular-homing T cells and memory T cells, respectively. Memory TFH cells were identified as CD3+CD8-CD4+CXCR5+CD45RO+PD1+. Central memory T cells were identified based on CCR7 expression. Relationship between the proportions of follicular-homing CD4 T cells and memory B cells were determined in multivariable regression models.ResultsHighly viremic HIV-infected children had lower proportions of memory TFH cells when compared with community control children. In multivariable analyses, high proportions of memory TFH cells were associated with increased percentages of resting memory B cells after adjusting for other covariates.ConclusionThe impact of HIV on follicular helper T cells could influence the accumulation of memory B cells in HIV-infected children.引言：人类免疫缺陷病毒（HIV）可导致儿童出现记忆B细胞（memory B cells）功能缺陷，但此类缺陷的具体发病机制尚未完全阐明。其中一种可能的机制是免疫反应过程中T细胞对B细胞的辅助作用缺失。然而，目前鲜有研究探讨HIV对儿童滤泡辅助T细胞（follicular helper T cells）的影响。 方法：本研究对HIV感染儿童的滤泡归巢CD4 T细胞与记忆B细胞进行了检测分析，并与社区对照儿童进行对比。分别以CXCR5和CD45RO作为滤泡归巢T细胞与记忆T细胞的表面标记物。记忆性TFH细胞的鉴定表型为CD3+CD8-CD4+CXCR5+CD45RO+PD1+。中枢记忆T细胞则通过CCR7的表达情况进行鉴定。通过多变量回归模型分析滤泡归巢CD4 T细胞比例与记忆B细胞比例之间的相关性。 结果：高病毒载量的HIV感染儿童其记忆性TFH细胞比例较社区对照儿童更低。多变量分析结果表明，在校正其他协变量后，较高的记忆性TFH细胞比例与静息型记忆B细胞比例升高显著相关。 结论：HIV对滤泡辅助T细胞的影响可能会影响HIV感染儿童体内记忆B细胞的积累。