HIV-1感染者CD4＋CD25^nt/hi CD127^lo调节性T细胞PD-1表达水平与疾病进展的关系

Association of PD-1 expression on CD4^+ CD25^(nt/hi) CD127^(lo) regulatory T cells with disease progression in HIV-1 infected patients

目的:阐明HIV-1感染者外周血中具有CD4+CD25nt/hiCD127lo特征的调节性T细胞(Treg)表面PD-1的表达水平与疾病进展的关系。方法:选取108名未经治疗的不同进展期的HIV-1感染者和27名健康人对照,采集静脉血,用Ficoll-Hypaque密度梯度离心法分离获得PBMC,加入PerCP-CD4抗体、FITC-CD25抗体、PE-CD127抗体和APC-PD-1抗体,经细胞表面四色染色、流式细胞术(FCM)分析Treg表面PD-1的表达;另将50 L全血加入Trucount绝对计数管,采用Multitest CD3/CD8/CD45/CD4试剂盒检测CD4+T细胞绝对数;分离静脉血血浆,NucliSens EasyQ测定血浆HIV-1病毒载量;实验数据采用SPSS14.0统计学软件分析处理。结果:HIV-1感染者Treg表面PD-1表达水平显著高于健康人(5.33%±2.24%vs1.72%±0.65%,P<0.01);AIDS期(7.87%±2.23%)明显高于进展期(5.21%±1.72%,P<0.05)和新近感染者(3.22%±1.01%,P<0.05);HIV-1感染者Treg表面PD-1表达水平与血浆中的HIV-1病毒载量和CD4+T细胞绝对数密切相关。结论:首次证实HIV-1感染者外周血中Treg表面PD-1表达增加,且表达水平与病程进展相关。该结果为进一步揭示HIV-1感染中Treg的效应机制、探索新的免疫治疗方案提供了理论及实验依据。

AIM： To investigate whether Programmed death-1 （PD-1） expression on peripheral CD4＋ CD25^nt/hi CD127^lo regulatory T cells （Treg） was associated with disease progression in HIV-1-infected patients. METHODS： Peripheral blood from 108 HIV-1-infected patients in distinct disease progression statuses and 27 healthy individuals were collected in the present investigation. PBMCs were isolated by centrifugation on FicolI-Hypaque, followed by staining with anti-CD4-PerCP, anti-CD25-FITC, anti-CD127- PE and anti-PD-I-APC. PD-I expression on Treg was analyzed by four-color staining flow cytometry. CD4＋ T cell absolute counts were determined using Multitest CD3/CD4/ CD8/CD45 kit and plasma viral loads were detected on NucliSens EasyQ. All data were analyzed using SPSS14.0 software. RESULTS： In peripheral blood of healthy individuals, Treg expressed PD-1 at very low levels （1.72% ±0.65%）. In contrast, Treg from HIV-1-infected patients showed a significantly increased PD-1 expression （5.33% ± 2.24%, P 〈 0.01）. Moreover, AIDS patients exhibited statistically higher PD-1 expression on Treg （7. 87% ± 2.23% ） than newly HIV-1 infected patients （3.22% ± 1.01%, P 〈 0.05） and patients in progression to AIDS（5.21% ± 1.72%, P〈0.05）. PD-1 up-regulation on Treg was closely correlated with reduced CD4＋ T cell absolute counts but elevated plasma viral load. CONCLUSION： Overall, we found that PD-1 expression on peripheral Treg was up-regulated and correlated with disease progression in HIV-1-infected patients for the first time. These findings not only extend our understanding of how Treg functions in HIV-1-infected patients but also support the notion that blocking PD-1/PD-L1 interactions may represent a potential therapeutic strategy for HIV-1-infected patients.