Gut mucosal T cell responses and gene expression correlate with protection against disease in long-term HIV-1-infected nonprogressors

Limited information is available on the molecular mechanisms by which long-term HIV-1-infected nonprogressors suppress HIV-1 infection and maintain immune functions. The intestinal mucosal immune system is an early target for HIV-1 infection and severe CD4+ T cell depletion. We evaluated mucosal T lymphocyte subsets, virus-specific cellular responses, gene expression profiles, and viral loads in intestinal mucosal biopsies of long-term nonprogressor (LTNP) patients as compared to chronically HIV-1-infected patients with high viral loads (HVLs) and CD4+ T cell loss, as well as HIV-seronegative healthy individuals. This study aims to identify the mucosal correlates of HIV disease progression and to determine the molecular changes associated with immune and intestinal dysfunction. LTNP patients had undetectable viral loads, normal CD4+ T cell levels, and virus-specific cellular responses in peripheral blood and mucosal compartments. Microarray analysis revealed a significant increase in gene expression regulating immune activation, cell trafficking, and inflammatory response in intestinal mucosa of HVL patients as compared to LTNP patients. Genes associated with cell cycle regulation, lipid metabolism, and epithelial cell barrier and digestive functions were down-regulated in both HVL and LTNP patients. This may adversely influence nutrient adsorption and digestive functions, with the potential to impact the efficacy of antiretroviral therapy. We demonstrate that the maintenance of mucosal T cells, virus-specific responses, and distinct gene expression profiles correlate with clinical outcome in LTNP patients. However, the intestinal mucosal immune system remains an important target of HIV-1 infection in LTNP, and these effects may ultimately contribute toward disease progression.     

HIV-1 strains from a cohort of American subjects reveal the presence of a V2 region extension unique to slow progressors and non-progressors

OBJECTIVES: To determine the molecular nature of HIV-1 quasispecies and their evolution, in vivo over time, in an American cohort of 22 homosexual men [four rapid progressors (RP), 15 slow progressors (SP) and three long-term non-progressors (LTNP)], infected with HIV-1 between 1982 and 1983, and to assess the possible role of the HIV-1 V2 region extension in HIV disease progression. DESIGN: Genetic and phylogenetic analyses of the V3 region and the nef gene clones over time from uncultured peripheral blood mononuclear cells (PBMC) of American patients with varying HIV disease progression rates. METHODS: Proviral DNA from longitudinally collected uncultured PBMC were subjected to PCR amplification in the nef gene and env V2 and V3 regions, followed by cloning, sequencing and phylogenetic analysis to establish evolutionary relationships between HIV-1 strains over time. RESULTS: Analysis of multiple viral clones showed nef gene deletions/insertions in 10 out of 15 SP, along with the coexistence of intact and defective nef gene lineages in the same individual over time, whereas these nefgene abnormalities were absent from HIV-1 strains from LTNP. Increasing quasispecies diversity in HIV-1 strains, over time, abrogation of a V3 region N-linked glycosylation site in > 60% of the clones, and, importantly, an extended V2 region were unique features of HIV-1 strains from SP and LTNP. CONCLUSIONS: The V2 region extension was unique to only SP and LTNP, and so may have a role in slow progression or non-progression of HIV disease. Increasing genetic diversity in HIV-1 strains in SP and LTNP correlated with the immunocompetent status of the host.     

Stable changes in CD4+ T lymphocyte miRNA expression after exposure to HIV-1

MicroRNAs (miRNAs) inhibit HIV-1 expression by either modulating host innate immunity or by directly interfering with viral mRNAs. We evaluated the expression of 377 miRNAs in CD4(+) T cells from HIV-1 élite long-term nonprogressors (éLTNPs), naive patients, and multiply exposed uninfected (MEU) patients, and we observed that the éLTNP patients clustered with naive patients, whereas all MEU subjects grouped together. The discriminatory power of miRNAs showed that 21 miRNAs significantly differentiated éLTNP from MEU patients and 23 miRNAs distinguished naive from MEU patients, whereas only 1 miRNA (miR-155) discriminated éLTNP from naive patients. We proposed that miRNA expression may discriminate between HIV-1-infected and -exposed but negative patients. Analysis of miRNAs expression after exposure of healthy CD4(+) T cells to gp120 in vitro confirmed our hypothesis that a miRNA profile could be the result not only of a productive infection but also of the exposure to HIV-1 products that leave a signature in immune cells. The comparison of normalized Dicer and Drosha expression in ex vivo and in vitro condition revealed that these enzymes did not affect the change of miRNA profiles, supporting the existence of a Dicer-independent biogenesis pathway.     

Mutation, fitness, viral diversity, and predictive markers of disease progression in a computational model of HIV type 1 infection

The aim of this study was to develop a computational model of HIV infection able to simulate the natural history of the disease and to test predictive parameters of disease progression. We describe the results of a numerical simulation of the cellular and humoral immune response to HIV-1 infection as an adaptive pathway in a "bit-string" space. A total of 650 simulations of the HIV-1 dynamics were performed with a modified version of the Celada-Seiden immune system model. Statistics are in agreement with epidemiological studies showing a log normal distribution for the time span between infection and the development of AIDS. As predictive parameters of disease progression we found that HIV-1 accumulates "bit" mutations mainly in the peptide sequences recognized by cytotoxic CD8 T cells, indicating that cell-mediated immunity plays a major role in viral control. The viral load set point was closely correlated with the time from infection to development of AIDS. Viral divergence from the viral quasispecies that was present at the beginning of infection in long-term nonprogressors (LTNP) was found to be similar to that found in rapid progressors at the time CD4 T cells drop below the critical value of 200 cells/microl. In contrast, the diversity indicated by the number of HIV strains present at the same time was higher for rapid and normal progressors compared to LTNP, suggesting that the early immune response can make the difference. This computational model may help to define the predictive parameters of HIV dynamics and disease progression, with potential applications in therapeutic and vaccine simulations.     

Different subsets of peripheral blood dendritic cells show distinct phenotypic and functional abnormalities in HIV-1 infection

OBJECTIVES: To analyse the distribution, expression of chemokine receptors and ex vivo production of inflammatory cytokines by peripheral blood (PB) monocytes and DC in HIV-1+ individuals. DESIGN: Dendritic cells (DC) play an important role in the establishment and dissemination of HIV infection. DC interaction with HIV depends on expression of HIV receptors and co-receptors. Accumulating evidence supports the notion that DC functionality is impaired in HIV-1+ patients. METHODS: PB samples from 30 naive-treated HIV-1+ progressors were studied. Additionally, 10 adult healthy volunteers (AHV), seven Hepatitis C virus positive (HCV+)/HIV-1- patients and five long-term non-progressor HIV-1+ patients (HIV-1+LTNP) were included as controls. Flow cytometry immunophenotyping was used for the identification, enumeration and characterization of monocytes and DC. RESULTS: PB myeloid DC (mDC) and plasmacytoid DC (pDC) were significantly decreased in HIV-1+ progressors, while unaltered in HIV-1+LTNP. The expression of CXCR2 and CXCR4 and of CXCR4 and CCR5 were severely altered on PB mDC and pDC from HIV-1+ progressors, respectively. By contrast, both the expression of the chemokine receptors analysed and the numbers of CD16+ DC in HIV-1+ progressors were not different from AHV, while altered in HCV+/HIV-1- and HIV-1+LTNP. Furthermore, PB monocytes and DC from HIV-1+ progressors spontaneously produced inflammatory cytokines, in contrast with AHV. CONCLUSIONS: These results support the existence of a selective interaction between HIV-1 and both mDC and pDC, associated with HCV co-infection-independent spontaneous production of inflammatory cytokines, reflecting the occurrence of in vivo activation of the immune system, which might further contribute to the impaired DC functionality.     

Clinicoimmunological progression and response to treatment of long-term nonprogressor HIV-hepatitis C virus-coinfected patients

We assess the severity and response to treatment of hepatitis C virus (HCV) infection in a cohort of long-term nonprogressors (LTNP) and analyze whether HCV infection affects the progression of HIV-1 infection. A case-control study comparing coinfected LTNP (n = 28) with coinfected normal progressors (NP) (n = 56) was performed. Signs of hepatopathy, response to HCV treatment, HIV viral load (VL), and lymphocyte T subsets were analyzed. A cohort of LTNP with (n = 28) and without HCV infection (n = 7) was compared to assess the influence of HCV on HIV-1 infection. Liver enzymes were lower in LTNP than in NP. There were no significant differences between LTNP and NP in clinical signs of chronic liver disease at physical examination, echostructure, degree of inflammation, or fibrosis score in liver biopsy. There were no differences in the response to HCV treatment between groups (57% vs. 45%, p = 0.69). LTNP presented a proportionally higher drop of CD4 during HCV treatment, which persisted 2 years after discontinuing treatment [-195, -10, and 30 cells/mm3 HCV-treated LTNP (n = 7), NP (n = 56), and non-HCV-treated LTNP (n = 21), respectively, p < 0.05]. There were no differences in any variables analyzed when coinfected and monoinfected LTNP were compared. LTNP do not seem to have a better outcome or response to HCV treatment than NP. HCV-treated LTNP could have a worse HIV progression than HIV-HCV-treated NP or untreated coinfected LTNP. HCV infection does not have a deleterious effect on the progression of LTNP.     

Conserved neutralizing epitopes of HIV type 1 CRF01_AE against primary isolates in long-term nonprogressors

Linear conserved B cell epitopes in envelope glycoprotein of long-term nonprogressors (LTNPs) HIV-1 CRF01_AE were determined. The envelope sequences of HIV-1 subtype E from Thailand were aligned to define consensus sequences. Then the peptides corresponding to these predicted regions were synthesized as peptides represent C1, C2, C3, C5, V2, V3, and gp41 regions. After that, the neutralizing B cell epitopes were determined by neutralized competitive assay with pool sera of typical progressor and LTNP HIV-1 CRF01_AE patients against HIV-1 CRF01_AE 24 primary isolates (PI) and laboratory strains (TCLA). We found that the strength and breadth of neutralization were greater for sera from LTNPs compared with sera from typical progressors. Peptides C1E and C2E could inhibit primary isolates but not the TCLA strain in LTNP sera. The new B cell epitopes, which were located in the C1 and C2 regions of CRF01_AE against primary HIV-1 isolates, were identified in HIV-1 CRF01_AE LTNPs. This may be important in HIV-1 vaccine development and trial.     

长期不进展人类免疫缺陷病毒-1感染者准种膜蛋白V3环氨基酸特点分析

目的 了解长期不进展HIV-1感染者HIV-1准种膜蛋白V3环氨基酸序列特征及变异特点.方法 应用终点有限稀释套式PCR方法,对5例长期不进展HIV-1感染者不同时间点单个HIV-1前病毒env基因c2-v3-c3区域进行扩增和序列测定,用序列确证分析技术分析env基因区V3环氨基酸序列特征.结果 5例患者不同随访时间点获得的准种序列中,V3环35个氨基酸中出现多样性的位点分别有1～10个不等,同一患者不同随访时间点准种优势株序列完全一致或仅有1～2个位点不同;4例患者V3环顶端四肽为GPGR,1例患者为GPGK,同一患者不同随访时间点V3环顶端四肽一致;根据V3环11和25位氨基酸及V3环的电荷推测HIV-1辅助受体均为趋化因子受体(CCR)5.结论 长期不进展HIV-1感染者V3环序列存在不同程度变异,顶端四肽稳定性高,感染的HIV-1毒株可能为非合胞体诱导型毒株.     

调节性T细胞稳态与慢性HIV-1感染引起的异常免疫活化研究

目的本研究旨在探讨CD4＋Foxp3＋调节性T细胞（regulatory Tcells,Treg）稳态与慢性HIV-1感染者疾病进程及免疫活化的相关性。方法选择50例慢性HIV-1感染者,包括AIDS患者15例（AIDS组）、典型进展（typical progressor,TP）患者25例（TP组）、长期非进（long-term non-progressor,LTNP）患者10例（LTNP组）,另选健康对照者（healthy control,HC）15例（HC组）。用流式细胞仪检测Treg的增殖标志Ki-67和凋亡标志半胱氨酰天冬氨酸蛋白酶-3,同时检测Treg的活化标志CD38和人白细胞抗原-DR。结果在HC组和慢性HIV-1感染者中,Treg的增殖和凋亡速率均显著高于CD4＋Foxp3非调节性T细胞,这种稳态的改变在TP组和AIDS组中更为明显。进一步研究发现Treg增殖和凋亡与其活化程度呈正相关。结论慢性HIV-1感染导致Treg的过度活化,进而导致Treg稳态的改变。Treg稳态可以作为预测HTV/AIDS患者疾病进展的一项指标。     

长期不进展人类免疫缺陷病毒-1感染者准种膜蛋白V3环氨基酸特点分析

目的 了解长期不进展HIV-1感染者HIV-1准种膜蛋白V3环氨基酸序列特征及变异特点.方法 应用终点有限稀释套式PCR方法,对5例长期不进展HIV-1感染者不同时间点单个HIV-1前病毒env基因c2-v3-c3区域进行扩增和序列测定,用序列确证分析技术分析env基因区V3环氨基酸序列特征.结果 5例患者不同随访时间点获得的准种序列中,V3环35个氨基酸中出现多样性的位点分别有1～10个不等,同一患者不同随访时间点准种优势株序列完全一致或仅有1～2个位点不同;4例患者V3环顶端四肽为GPGR,1例患者为GPGK,同一患者不同随访时间点V3环顶端四肽一致;根据V3环11和25位氨基酸及V3环的电荷推测HIV-1辅助受体均为趋化因子受体(CCR)5.结论 长期不进展HIV-1感染者V3环序列存在不同程度变异,顶端四肽稳定性高,感染的HIV-1毒株可能为非合胞体诱导型毒株.     

长期不进展人类免疫缺陷病毒-1感染者准种膜蛋白V3环氨基酸特点分析

目的 了解长期不进展HIV-1感染者HIV-1准种膜蛋白V3环氨基酸序列特征及变异特点.方法 应用终点有限稀释套式PCR方法,对5例长期不进展HIV-1感染者不同时间点单个HIV-1前病毒env基因c2-v3-c3区域进行扩增和序列测定,用序列确证分析技术分析env基因区V3环氨基酸序列特征.结果 5例患者不同随访时间点获得的准种序列中,V3环35个氨基酸中出现多样性的位点分别有1～10个不等,同一患者不同随访时间点准种优势株序列完全一致或仅有1～2个位点不同;4例患者V3环顶端四肽为GPGR,1例患者为GPGK,同一患者不同随访时间点V3环顶端四肽一致;根据V3环11和25位氨基酸及V3环的电荷推测HIV-1辅助受体均为趋化因子受体(CCR)5.结论 长期不进展HIV-1感染者V3环序列存在不同程度变异,顶端四肽稳定性高,感染的HIV-1毒株可能为非合胞体诱导型毒株.     

HIV感染长期不进展者与艾滋病患者HIV-1 gag特异性CD+8 T细胞应答

目的探讨欧美流行的人类免疫缺陷病毒(HIV)-1 B亚型株与我国HIV感染和艾滋病(AIDS)病人 gag特异性CD+8 T细胞应答交叉反应性.方法研究对象为长期不进展者(LTNP)7例和艾滋病患者9例,将覆盖HXB2 HIV-1 gag全长的125个重叠肽段组成11个肽段库作为抗原,用γ干扰素刺激原酶联免疫斑点试验方法检测LTNP和AIDS病人的特异性CD+8 T细胞应答,观察两组病人间的差异及其与CD+4 T细胞和病毒载量的相关性.结果 LTNP组和AIDS组HIV-1 gag特异性CD+8 T细胞应答强度分别为(1212±796)斑点形成细胞数(SFC)/106外周血单个核细胞(PBMC)和(182±203) SFC/106PBMC,识别肽段库的个数(间接反应了细胞毒性T淋巴细胞应答的宽度)分别为3.0±0.8和0.8±0.7,LTNP组显著高于AIDS组.CD+8 T细胞应答的强度和宽度与CD+4 T细胞计数呈正相关,与病毒载量呈负相关.结论欧美流行株与我国病毒株之间具有交叉反应性,HIV-1 gag特异性CD+8 T细胞应答在阻止疾病进展中可能发挥重要作用.     

陕西省HIV-1流行株膜蛋白基因 C2-V3区序列特征和亚型分析

目的了解陕西省HIV-1毒株的流行情况和亚型特征.方法用套式聚合酶链式反应(Nested-PCR)对6份采集于陕西省经确认为HIV-1感染者或艾滋病病人外周血淋巴细胞(PBMC)提取核酸,从6份样品中获得了HIV-1膜蛋白(ENV)基因的核酸片段进行扩增,并测定和分析了C2-V3及其邻区共312个核苷酸序列.结果 6份血样中,2份为HIV-1A亚型毒株感染(SHX7、SHX8);4份为HIV-1B'亚型(泰国B'亚型)毒株感染(SHX1、SHX5、SHX6、SHX9).SHX1、SHX5、SHX6、SHX9彼此间基因离散率为5.62%,SHX7与来自卢旺达的U08794之间的基因离散率仅为2.41%.结论陕西省目前存在HIV-1 A、B'两种亚型的毒株,HIV-1 B'亚型由邻近地区传入,HIV-1 A亚型为与非洲人接触传入.     

Expression of interleukin-15 and interleukin-15Rα in monocytes of HIV type 1-infected patients with different courses of disease progression

Interleukin-15 (IL-15) enhances the effector mechanisms of anti-HIV immune responses and thus is considered a potential adjuvant of HIV-1 vaccine. However, there are a lack of data concerning the relationships between IL-15 expression and regulation in HIV-1-infected patients and the course of disease progression. We found that IL-15, but not IL-15Rα, is expressed at significantly higher levels in the CD14(+) monocytes [stimulated or not with interferon (IFN)-γ] of long-term nonprogressors (LTNP) than in those of HIV-1 progressors or healthy controls. There was no between-group difference in the amounts of soluble IL-15 released from the cells. We also found that like the healthy controls, the LTNP expressed the IL-15 and IL-15Rα genes in a more coordinated manner than the progressors. Our findings show that there are significant differences in IL-15 expression between patients with different courses of HIV infection, and that the coordinated expression of the IL-15 and IL-15Rα genes is dysregulated in patients with progressive disease. They also provide important information concerning the mechanisms of infection and the potential use of IL-15 as a therapeutic agent.     

HLA B*5701 is highly associated with restriction of virus replication in a subgroup of HIV-infected long term nonprogressors

A unique cohort of HIV-1-infected long term nonprogressors (LTNP) with normal CD4(+) T cell counts and <50 copies/ml of plasma were prospectively recruited for study. HLA typing revealed a dramatic association between the HLA B*5701 class I allele and nonprogressive infection [85% (11 of 13) vs. 9.5% (19 of 200) in progressors; P < 0. 001]. Antigen-specific CD8(+) T cells were enumerated by flow cytometric detection of intracellular IFN-gamma in response to HIV antigens and HLA B*57-gag tetramer staining. No quantitative differences in the total HIV-specific CD8(+) T cell responses were observed between B*57(+) LTNP and five B*57(+) progressors (P = 0.4). Although similar frequencies of peptide specific CD8(+) T cells were also found, the gag-specific CD8(+) T cell response in the LTNP group was highly focused on peptides previously shown to be B*57-restricted. These findings indicate that, within this phenotypically and genotypically distinct cohort, a host immune factor is highly associated with restriction of virus replication and nonprogressive disease. They also strongly suggest a mechanism of virus specific immunity that directly operates through the B*5701 molecule. Further characterization of qualitative differences in the virus-specific responses that distinguish HLA B*57(+) LTNP from progressors may ultimately define mechanisms of effective immune mediated restriction of virus replication.     

Longitudinal quantification of human immunodeficiency virus type 1 DNA and RNA in long-term nonprogressors

Twenty patients with human immunodeficiency virus type 1 (HIV-1) infection for >7 years, no HIV-1-related symptoms, no treatment, and CD4+ cell counts >500/microL were included in a prospective study in 1993. Four years later, 12 patients had progressed (SPs), while 8 had not (long-term nonprogressors [LTNPs]). At inclusion, HIV-1 RNA, but not DNA, levels were higher in SPs. During follow-up, a consistent increase in HIV-1 RNA was seen in only 1 LTNP. In 2 LTNPs, plasma viremia was persistently undetectable or <110 copies/mL. Infectious virus was isolated from only 1 LTNP and from 11 SPs. In 4 LTNPs, HIV-1 DNA levels decreased spontaneously with time. The restricted viral replication and the declining HIV-1 DNA levels suggest that the HIV-1 infection can be controlled efficiently in a few LTNPs, leading to a decrease in the total virus burden with time.     

Increased plasma interleukin-7 level correlates with decreased CD127 and Increased CD132 extracellular expression on T cell subsets in patients with HIV-1 infection

BACKGROUND: Interleukin (IL)-7 levels are increased in patients with human immunodeficiency virus type 1 (HIV-1)-associated lymphopenia; however, the effects of this on IL-7 receptor (IL-7R) expression, disease progression, and immune reconstitution remain unclear. METHODS: Plasma IL-7 levels were measured, by enzyme-linked immunoassay, in patients with primary, chronic, or long-term nonprogressive HIV-1 infection (PHI, CHI, and LTNP, respectively) before and after 40-48 weeks of antiretroviral therapy (ART). Cell-surface expression and intracellular expression of the IL-7R components CD127 and CD132 were measured by flow cytometry. The effects of IL-7 and cycloheximide on IL-7R expression by peripheral blood mononuclear cells were examined in vitro. RESULTS: Plasma IL-7 levels were increased in both patients with PHI and those with CHI; administration of ART resulted in normalized plasma IL-7 levels in patients with PHI but not in those with CHI. Plasma IL-7 levels positively correlated with CD4(+) T cell immune reconstitution in patients with PHI. In vitro, exogenous IL-7 rapidly down-regulated cell-surface CD127 expression, but not CD132 expression, whereas subsequent reexpression required active protein synthesis. HIV-1 infection resulted in progressive decreases in the CD127(+)132(-) subset and increases in the CD127(-)132(+) subset of CD4(+) and CD8(+) T cells. Changes in CD4(+) T cell expression of IL-7R components were evident in patients with LTNP who lost viral control, and these changes preceded increases in plasma IL-7 levels. CONCLUSIONS: Perturbations in the IL-7/IL-7R system were clearly associated with disease progression but did not reliably predict immune reconstitution.     

HIV long-term non-progressors maintain brisk CD8 T cell responses to other viral antigens

OBJECTIVE: To examine the specificity of heightened CD8 cell responses in HIV-1-infected long-term non-progressors. DESIGN: Cross-sectional study examining CD8 cell responses to hepatitis C virus (HCV) peptides in HCV-HIV LTNP (n = 6), HCV-HIV progressors (n = 11), HCV singly infected patients (n = 32), HCV singly infected patients with self-limited disease (n = 10), HIV singly infected progressors (n = 7) and HCV-negative, HIV-negative controls (n = 10). METHODS: The frequency of HCV-reactive interferon gamma-producing cells in peripheral blood was assayed by enzyme linked immunospot assay using a panel of 61 HCV-1-derived peptides. RESULTS: Five of six HCV-HIV LTNP had HCV-specific CD8 responses. In contrast, responses were observed in 2 of 32 HCV singly infected patients, 2 of the 10 HCV singly infected patients with self-limited disease, and 0 of 11 HCV-HIV progressors (P < 0.001). Both frequency of HCV-specific CD8 cells and number of HCV peptides recognized were greater in HCV-HIV LTNP than in other groups. CONCLUSIONS: HIV-infected LTNP maintain heightened CD8 cell responses to HCV in addition to heightened HIV specific responses. Common mechanisms may underlie preservation of CD8 immune responses in these individuals. An improved understanding of these mechanisms will help to gain insight into protective antiviral immunity as well as to the means whereby these viruses impair host defenses.     

HIV-1-infected long-term non-progressors have milder mitochondrial impairment and lower mitochondrially-driven apoptosis in peripheral blood mononuclear cells than typical progressors

Mitochondrial parameters in peripheral blood mononuclear cells (PBMC) and their relationship with mitochondrially-driven PBMC apoptosis were investigated in a group of HIV-1-infected long-term nonprogressors (LTNP) and compared with untreated asymptomatic HIV-1 infected typical progressors (TP) and uninfected healthy controls (HC). Twenty-six LTNP, 27 TP and 31 HC were evaluated. Studies were performed in PBMCs. Mitochondrial DNA content (mtDNA) was assessed by quantitative real-time PCR. Activities of mitochondrial respiratory chain complexes (MRC) II, III and IV were determined by spectrophotometry. Caspase-3 activity was assessed by fluorimetry, and caspase-9 activation and Bcl-2 levels were assessed by immunoblotting. mtDNA abundance (p<0.05), MRC complex II (p<0.001), complex III (p<0.01) and complex IV (p=0.01) were lower in the TP group than in the HC group. In the LTNP group these parameters were similar to those of the HC group except for complex II, which was decreased (p<0.01). The PBMC of TP showed the highest overall apoptotic activation, since their caspase-3 activity was greater than that of HC (p<0.05) and LTNP. In the case of LTNP, however, the difference was non-significant. Caspase-9 and the caspase-9/Bcl-2 ratio were both over-expressed in TP compared to HC (p<0.01) and LTNP (p<0.05). Both of these measurements indicate that mitochondrially-driven apoptosis in TP is greater than in LTNP and HC. A relationship between mitochondrial damage and apoptotic activation was found in TP. Mitochondrial damage is associated with increased PBMC apoptosis in patients with active HIV-1 replication (TP). These abnormalities are slight or not present in LTNP.     

Low expression of inhibitory natural killer receptors in CD8 cytotoxic T lymphocytes in long-term non-progressor HIV-1-infected patients

We investigated whether a different pattern of HLA-specific inhibitory natural killer receptor (iNKR) expression on peripheral blood mononuclear cells (PBMC) of long-term non-progressor (LTNP) patients explained their benign course of HIV-1 infection. The surface expression of p70, p140 and CD94/NKG2A in their CD3+CD8+ PBMC was comparable to that of uninfected donors. The lack of iNKR-mediated functional inhibition of HIV-1-specific cytotoxic T lymphocytes in vitro could provide an additional mechanism for the efficient control of virus spread in LTNP patients.