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We performed a genome-wide association study comparing a cohort of 144 human immunodeficiency virus (HIV type 1-infected, untreated white long-term nonprogressors (LTNPs) with a cohort of 605 HIV-1-infected white seroconverters. Forty-seven single-nucleotide polymorphisms (SNPs), located from class I to class III major histocompatibility complex (MHC) subregions, show statistical association (false discovery rate, <0.05) with the LTNP condition, among which 5 reached genome-wide significance after Bonferonni correction. The MHC LTNP-associated SNPs are ordered in ≤4 linkage disequilibrium blocks; interestingly, an MHC class III linkage disequilibrium block (defined by the rs9368699 SNP) seems specific to the LTNP phenotype. [ABSTRACT FROM AUTHOR]

A double-blinded, controlled study of vaccination of untreated patients with chronic human immunodeficiency virus type 1 (HIV-1) infection with 3 doses of autologous monocyte-derived dendritic cells (MD-DCs) pulsed with heat inactivated autologous HIV-1 was performed. Therapeutic vaccinations were feasible, safe, and well tolerated. At week 24 after first vaccination (primary end point), a modest significant decrease in plasma viral load was observed in vaccine recipients, compared with control subjects (P = .03). In addition, the change in plasma viral load after vaccination tended to be inversely associated with the increase in HIV-specific T cell responses in vaccinated patients but tended to be directly correlated with HIV-specific T cell responses in control subjects. [ABSTRACT FROM AUTHOR]

INITIO is an open-labelled randomized trial evaluating first-line therapeutic strategies for human immunodeficiency virus-1 (HIV-1) infection. In an immunology substudy a tetanus toxoid booster (TTB) immunization was planned for 24 weeks after initiation of highly active antiretroviral therapy (HAART). All patients had received tetanus toxoid immunization in childhood. Generation of proliferative responses to tetanus toxoid was compared in two groups of patients, those receiving a protease inhibitor (PI)-sparing regimen ( n = 21) and those receiving a PI-containing ( n = 54) regimen. Fifty-two participants received a TTB immunization [PI-sparing ( n = 15), PI-containing ( n = 37)] and 23 participants did not [PI-sparing ( n = 6) or PI-containing ( n = 17)]. Cellular responses to tetanus antigen were monitored by lymphoproliferation at time of immunization and every 24 weeks to week 156. Proportions with a positive response (defined as stimulation index ≥ 3 and Δ counts per minute ≥ 3000) were compared at weeks 96 and 156. All analyses were intent-to-treat. Fifty-two participants had a TTB immunization at median 25 weeks; 23 patients did not. At weeks 96 and 156 there was no evidence of a difference in tetanus-specific responses, between those with or without TTB immunization ( P = 0·2, P = 0·4). There was no difference in the proportion with response between those with PI-sparing or PI-containing regimens at both time-points ( P = 0·8, P = 0·7). The proliferative response to tetanus toxoid was unaffected by initial HAART regimen. Anti-tetanus responses appear to reconstitute eventually in most patients over 156 weeks when treated successfully with HAART, irrespective of whether or not a TTB immunization has been administered. [ABSTRACT FROM AUTHOR]

Background. Kaposi sarcoma (KS) occurs mainly in immunocompromised patients and is strongly associated with infection with human herpesvirus 8 (HHV-8; also known as 'KS-associated herpesvirus'). We hypothesized that KS is linked to deficiencies in specific anti-HHV-8 T cell immunity. Methods. We studied asymptomatic HHV-8 carriers coinfected with human immunodeficiency virus (HIV; n=23) and patients with HIV-related or classic KS (n=29). We used an interferon-gamma enzyme-linked immunospot assay with 56 specific peptides distributed on 6 HHV-8 proteins (glycoprotein [gp] B, gpH, gp35/37, latent nuclear antigen 1 [LANA-1], K12, and K15) to detect HHV-8-specific T cell responses. Results. We found that patients with KS responded to these peptides less often and had much lower HHV-8-specific T cells counts than did asymptomatic HHV-8 carriers (P=.001 and P=.0004, respectively), regardless of CD4 T cell count or HHV-8 load. The frequency of Epstein-Barr virus-specific T cells was similar in both groups. Conclusions. Our results suggest that HIV-related and classic KS are associated with a lack of HHV-8-specific T cells. Also, we have described 8 new HHV-8 T cell epitopes in LANA-1, K12, and K15, including 2 CD4 T cell epitopes. These data provide new insight into HHV-8 cellular immunity. Copyright © 2006 Infectious Diseases Society of America [ABSTRACT FROM AUTHOR]

The European collaborative study of HIV-infected pregnant women in Europe now indicates a 13% risk of fetal HIV infection (originally thought to be about 30%, and possibly higher in some countries)- Several reports suggest transplacental passage. However, the detailed mechanisms associated with such vertical transmission have not yet been clarified. We have examined the possibility that HIV enters placental tissue from maternal blood via binding to CD4 and Fc receptors (FcR) at the trophoblast level, allowing intraplacental infection. Here we report the detection of several FcR with distinct localization in the placental villus as well as CD4 surface expression on human trophoblast cells. In addition, we show that trophoblastic cells interact specifically with the gp120/gp160 viral envelope protein. By their tissue localization, these receptors could be responsible or the entry of HIV into the fetal placental cells. Furthermore, purified placental cells can be directly infected by HIV in vitro, and the infection is inhibited by soluble CD4. This suggests a crucial role of the CD4 receptor but an additional way of entry cannot be excluded. Such an in vitro model may be suitable for further studies concerning placental HIV transmission and its prevention. [ABSTRACT FROM AUTHOR]

The γ/δ T cell receptor is expressed on 1-15% of normal human peripheral blood lymphocytes (PBL). This subpopulation is recognized by anti-TcR-δ1 MoAb which is functionally defined as a pan-δ MoAb. Two other antibodies, anti-Ti-γA and anti-δ-TcS1 are directed at variable determinants of either the γ or the δ chain, respectively. In normal individuals anti-Ti-γA characterizes two thirds of the TcR-δ1+ subpopulation whereas anti-delta TcS1 reacts with most of the δ-TcR1+, Ti-γA- cells. In the present study, we have used these three MoAbs to characterize the TcR γ/ δ+ peripheral lymphocytes during HIV infection. Fifty patients at three distinct clinical stages (SPC/PGL, ARC, AIDS) of the infection have been studied. The Ti-γA+ subset in the whole group accounted for 3.45% of PBL and did not differ from controls; it was also unchanged when the three groups were analysed separately. The Ti-γA circulating cells were in a resting state as assessed by the absence of surface- expressed activation markers. In contrast, in some patients the proportion of circulating TcR-δ1+, Ti-γA-, δTcS1+ cells was increased (4.75%) leading to an inversion of the Ti-γA/δ-TcS1 ratio. Altogether, those data suggest a conservation of the Ti-γA+ subset during HIV infection, contrasting with an increase of the δ-TcS1+, Ti-γA- fraction in some cases. [ABSTRACT FROM AUTHOR]

Major expansions of CD8hi+CD57+ T lymphocytes frequently occur during human immunodeficiency virus (HIV) infection and after transplantation. To investigate mechanisms of such cell expansion, we compared the activation and functional status of CD8hi+CD57+ and CD57- peripheral blood lymphocytes (PBL) from normal, bone marrow transplantation (BMT) and HIV+ donor. The CD8hi+CD57+PBL from BMT and HIV+ donors preferentially displayed CD38 and HLA-DR activation markers without correlation between CD8hi+CD57+ percentages and HIV load, the CD45RA+ isoform in all ex vivo conditions but acquired CD45RO after in vitro expansion, CD11b and CD11c in BMT and HIV+ donors but decreased expression of CD62-L, VLA-2 and VLA-6. The CD8hi+CD57+ cells were positive for perforin and granzyme B and spontaneously mediated cytolytic activity in a CD3-redirected assay. In contrast the inhibitor of cytolytic functions (ICF) produced by CD8hi+CD57+ cells down-modulated the CD3-redirected cytolytic activity but only at low levels of CD3 cross-linking. While CD3-triggering induced a low, if any, short-term proliferation of CD8+CD57+ cells, this subset could be amplified after long-term stimulation either with mitogens or with HIV antigens, thereby enriched in HIV-specific T cells producing tumor necrosis factor-α. Altogether these data suggest that CD8hi+CD57+ cells represent a terminal differentiation state of activated effector cytotoxic T lymphocytes which are enriched in antigen-specific T cells and down-modulate their own cytolytic potential, thus participating in a negative control of effector cell functions during persistent viral infections or transplantations. [ABSTRACT FROM PUBLISHER]

The aim of this study was to investigate the peripheral blood lymphocyte (PBL) phenotypes and T cell repertoire in patients with HCV infection, with or without mixed cryoglobulinaemia (MC). The patients were: Group 1, 23 patients with HCV infection and MC; Group 2, 14 patients with HCV infection but without MC; Group 3, 10 patients with symptomatic essential MC. Twenty healthy blood donors were used as controls. Blood lymphocyte counts were determined, and flow cytometry was used to measure proportions of B cells (CD19+), natural killer (NK) cells (CD16+ CD56+), T cells (CD3+), CD4+ T cell subsets (memory CD4+ CD45RO+; naive CD4+ CD45RO-; Th0/Th2 CD4+ CD7-; activated CD4+ CD25+), and CD8+ T cell subsets (immunoregulatory CD8+ CD57+; cytotoxic CD8+ S6F1+, activated CD8+ CD25+). Bias in the usage of T cell receptor (TCR) Vβ chains was studied in a subgroup of 10 representative patients of Group 1 using a polymerase chain reaction (PCR) analysis of the Vβ segments with a series of 20 oligonucleotides specific for the Vβ families. The three groups were comparable for blood lymphocyte counts, and we observed no abnormal repartition of the following PBL subsets: T cells (CD3+), CD4+ and CD8+ subpopulations, B cells (CD19+), and the NK cells (CD16+ 56+). In none of the groups could we observe lymphocyte ex vivo activation as assessed by the normal expression of the activation cell markers: CD25 on CD4+ or CD8+ T cells, or CD5 on B cells. The repartition of naive and memory (CD45RO-/RO+) CD4+ T cells was normal and we did not observe any amplification of the CD4+ CD7- T cell subset differentiated in... [ABSTRACT FROM AUTHOR]