Inefficient Nef-Mediated Downmodulation of CD3 and MHC-I Correlates with Loss of CD4+ T Cells in Natural SIV Infection

Recent data suggest that Nef-mediated downmodulation of TCR-CD3 may protect SIVsmm-infected sooty mangabeys (SMs) against the loss of CD4+ T cells. However, the mechanisms underlying this protective effect remain unclear. To further assess the role of Nef in nonpathogenic SIV infection, we cloned nef alleles from 11 SIVsmm-infected SMs with high (>500) and 15 animals with low (<500) CD4+ T-cells/µl in bulk into proviral HIV-1 IRES/eGFP constructs and analyzed their effects on the phenotype, activation, and apoptosis of primary T cells. We found that not only efficient Nef-mediated downmodulation of TCR-CD3 but also of MHC-I correlated with preserved CD4+ T cell counts, as well as with high numbers of Ki67+CD4+ and CD8+CD28+ T cells and reduced CD95 expression by CD4+ T cells. Moreover, effective MHC-I downregulation correlated with low proportions of effector and high percentages of naïve and memory CD8+ T cells. We found that T cells infected with viruses expressing Nef alleles from the CD4low SM group expressed significantly higher levels of the CD69, interleukin (IL)-2 and programmed death (PD)-1 receptors than those expressing Nefs from the CD4high group. SIVsmm Nef alleles that were less active in downmodulating TCR-CD3 were also less potent in suppressing the activation of virally infected T cells and subsequent cell death. However, only nef alleles from a single animal with very low CD4+ T cell counts rendered T cells hyper-responsive to activation, similar to those of HIV-1. Our data suggest that Nef may protect the natural hosts of SIV against the loss of CD4+ T cells by at least two mechanisms: (i) downmodulation of TCR-CD3 to prevent activation-induced cell death and to suppress the induction of PD-1 that may impair T cell function and survival, and (ii) downmodulation of MHC-I to reduce CTL lysis of virally infected CD4+ T cells and/or bystander CD8+ T cell activation

Expression of CD69 on T-cell subsets in HIV-1 disease

CD69 is the earliest activation marker newly synthesized and expressed during T lymphocyte activation. In this study, a whole-blood flow-cytometry-based assay was used to assess expression of the activation antigen CD69 on CD4 and CD8 T lymphocytes, and the co-expression of CD69 and CD28 on T cells. The expression of CD69 was studied in both unstimulated and in phytohaemagglutinin (PHA)- or anti-CD3/CD28-stimulated, 4-h culture, samples. The production of IL-2, IFN-γ or both cytokines, in CD69+ T cells, in response to Staphylococcus enterotoxin B was also tested. Fifty-three HIV-1-infected and 21 healthy volunteers participated in this study. In both PHA- and anti-CD3/CD28-stimulated cultures the percentage of CD69 on CD3+CD4+ T cells was significantly lower in AIDS (and non-responders to HAART) versus healthy controls and the other HIV-1(+) groups. A decrease of CD69+CD28+ T cells after PHA or MoAbs stimulation is noticed in AIDS. No difference in cytokine production was noticed between healthy volunteers and HIV-1(+) patients. Our results suggest that the expression of CD69 is affected only in the AIDS stage and in the non-responders to HAART patients. © 2008 Informa UK Ltd (Informa Healthcare, Taylor &amp; Francis AS)

Limited Long-Term Naive CD4+ T Cell Reconstitution in Patients Experiencing Viral Load Rebounds during HAART

Long-term (3.5 years) immune reconstitution in relation to viral load response was determined. Plasma HIV-1 RNA was suppressed in 40 patients (full responders) up to 42 months, and 17 patients achieved partial response. The measurements of CD4+ and CD8+ T lymphocyte subsets (CD45RA, CD45RACD62L, CD45RO, CD28, CD38) were carried out by flow cytometry. Full responders had a significant increase of CD4+ and all CD4 + T subsets both up to 6 and from 6 to 42 months, while the increase for partial responders was only up to 6 months. By 6 months, higher slopes were observed in full versus partial responders in the % of CD28 on CD4+ and the % of CD4+ memory subset and in both naïve and memory CD4+ subsets from 6 to 42 months. The percentage of CD8+ and its subsets was decreased significantly in full responders both up to 6 and from 6 to 42 months (except for an increase in the CD8+CD45RA + CD62L+ cells), while in partial responders this decrease was only up to 6 months. Lower slopes were observed in full versus partial responders from 6 to 42 months in the percentages of CD8+, CD8+CD45RO+, CD8+CD28-, and CD8 +CD38+ T cells. In conclusion, full responders have a stronger long-term naive CD4+ T cell subset reconstitution than partial responders. © 2004 Wiley-Liss, Inc

Comparative evaluation of the BTAstat test, NMP22, and voided urine cytology in the detection of primary and recurrent bladder tumors

Objectives. This prospective study was undertaken to evaluate the diagnostic efficacy of the BTAstat test and nuclear matrix protein (NMP22) compared with voided urine cytology (VUC) in the detection of primary and recurrent bladder cancer. Methods. A total of 147 patients provided a single voided urine sample for the BTAstat test, NMP22, and cytology prior to cystoscopy. Eighty-five of them had no bladder cancer history, whereas the remaining 62 were monitored for superficial bladder cancer. A group of 21 healthy age-matched volunteers were also enrolled in the study. Results. Bladder cancer was confirmed histologically in 99 patients, of which 62 had primary tumors and 37 had recurrent ones. The overall sensitivity and specificity were 71.7% and 56.5% for the BTAstat test, 62.6% and 73.9% for NMP22, and 38.4% and 94.2% for VUC. The optimal threshold value for NMP22 calculated with receiver operating characteristics curve, was 8 U/mL. BTAstat test was significantly more sensitive than VUC in detecting bladder cancer in all stage and grade subgroups, except GIII. On the contrary, NMP22 was significantly more sensitive than VUC only in stage Ta, grade I and II patients. BTAstat test had higher but not significantly different sensitivity than NMP22. Conclusions. Our data indicate a superiority of both BTAstat test and NMP22 over VUC in the detection of bladder cancer. Comparing BTAstat test with NMP22, the former proved to be more sensitive, whereas the latter was more specific. Ruling out diseases with potential interference can increase the overall specificity of both tests. False-positive results of either test in patients followed up for bladder cancer seem to correspond to future recurrences. UROLOGY 55: 871-875, 2000. (C) 2000, Elsevier Science Inc

Human herpesvirus-8 seropositivity and clinical correlations in HIV-1-positive and highly exposed, persistently HIV-seronegative individuals in Greece

The prevalence of anti-human herpesvirus 8 (HHV- 8) antibodies was retrospectively assessed in a cohort of 248 consecutive HIV-1-positive patients followed up in an academic unit in Greece during a 14-year period and in 46 highly exposed, persistently HIV-seronegative (HEPS) individuals. The impact of the initial anti-HHV-8 status on tumorgenesis and mortality was studied. The first available serum sample from the department’s pool was tested. Demographics and data regarding history of sexually transmitted diseases, Hepatitis B surface antigen (HbsAg) and hepatitis C (HCV) status were collected. Patients who developed either HHV-8-related or non-HHV-8-related neoplasms during long-term follow-up were also identified. Forty-eight percent of the HIV-1-positive patients and 56% of the HEPS subjects were found anti-HHV-8-positive. No difference was observed regarding the development of HHV-8-related or non-HHV-8-related neoplasia and mortality on grounds of initial anti-HHV- 8 status. Mortality was positively associated with the presence of HBsAg. HCV infection showed a trend to be more common in anti-HHV-8-positive patients. In summary, the seroprevalence of HHV-8 among HIV-1- positive patients is higher than the one reported in the Western world. The initial anti-HHV-8 status is not a prognostic factor in HIV-1- positive individuals. The high seroprevalence in HEPS individuals possibly reflects their risk- prone lifestyle. HbsAg-positive status is a long- term negative prognostic factor in HIV infection

Costimulatory molecules in Wegener's granulomatosis (WG): lack of expression of CD28 and preferential up-regulation of its ligands B7-1 (CD80) and B7-2 (CD86) on T cells

T cells are most likely to play an important role in the pathogenesis of WG, and recently a predominant Th1 pattern of immune response has been demonstrated in granulomatous inflammation. Since the expression of costimulatory molecules has a significant impact on the cytokine profile and proliferation response of T cells, the goal of this study was to characterize the expression of costimulatory molecules (CD28, CTLA-4 (CD152), B7-1 (CD80), B7-2 (CD86)) on T cells, monocytes and B cells in WG, and to correlate the findings with clinical parameters such as disease activity, extent and therapy. WG patients (n = 24) and healthy controls (HC; n = 17) were examined for the expression of costimulatory molecules by fluorescence-activated cell sorter analysis, both in whole peripheral blood and after in vitro activation of T cells and antigen-presenting cells. Results were correlated with clinical data. The expression of CD28 on CD4+ and CD8+ cells was significantly lower in WG than in HC (CD28+ 81.4% in WG versus 97.9% of CD4+ cells (P < 0.0001); CD28+ 44.6% in WG versus 68.5% of CD8+ cells (P < 0.00001)), both in peripheral blood and after in vitro activation. A lower percentage of monocytes was B7-2+ in WG than in HC in peripheral blood, whereas no significant differences in the expression of B7-1 and B7-2 were observed after in vitro stimulation of monocytes and B cells. After in vitro activation a significantly higher percentage of B7-1+ and B7-2+ T cells was seen in WG. There was no significant difference in the CTLA-4 expression pattern between WG and HC. The percentage of CD28+ lymphocytes correlated negatively with the Disease Extent Index cumulated over the course of disease (r = −0.46, P = 0.03), indicating a more severe manifestation in patients with lower CD28 expression. Correlations with other clinical parameters such as activity or therapy were not seen. WG patients show a lack of CD28 expression on T cells and an unusual up-regulation of its ligands B7-1 and B7-2 on T cells after in vitro activation as well as a lower expression of B7-2 on freshly isolated monocytes compared with HC. These features might promote the Th1 cytokine pattern and thereby contribute to persistently high levels of immune activation in WG