Search

During immunosuppressive medication, Epstein-Barr virus (EBV) infection is associated with a risk of developing posttransplant lymphoproliferative disease (PTLD). The appropriateness of a spontaneous EBV B-cell transformation (SET) assay as a monitor of EBV-specific immunity was evaluated to investigate if it safely allows reducing immunosuppressive medication, thereby decreasing the risk of developing PTLD. PBMC were isolated longitudinally from 20 pediatric renal allograft recipients treated with prednisone and cyclosporine combined with either azathioprine or mycophenolate mofetil. Most significantly, EBV-peptide-specific CD8+ T cells were detectable in the blood of patients with negative SET assays, coinciding with significantly lower EBV loads, whereas these cells were less frequent in the blood of patients with positive SET assays. Reducing the levels of immunosuppression resulted in normalization of the SET assays. Therefore, the SET assay is a reflection of the interaction between viral replication, transformation of B cells, and EBV-specific immunity in vivo and hence a valuable screening test for EBV-driven lymphoproliferative phenomena in allograft recipients.

Objective: Using SCID-Hu mice models and in vitro culture systems, it has been shown that syncytium inducing/CXCR4 using (X4) HIV-1 variants affect thymic function through infection and killing of CXCR4 thymocytes. The effect of X4-emergence on naive, memory and effector T-cell subset kinetics in vivo is, however, not known. Design: Prospective cohort study. Methods: Analysis of changes in naive, memory and effector CD4 and CD8 T-cell numbers and cell division before and after the emergence of X4 variants. Results: Significantly lower numbers of CD4 T cells in patients with X4 variants (n = 18) compared to patients with non-syncytium inducing/CCR5 using variants (n = 74) were due to increased loss of naive and CD27 memory CD4 T cells. In addition, emergence of X4 variants was associated with a small but significant decline in naive CD8 T-cell numbers and increased proportions of dividing CD4 and CD8 naive, memory and effector T cells. Conclusion: Loss of naive T cells may suggest thymic dysfunction, however, such an effect would explain only part of the accelerated naive CD4 T-cell decline because of the longevity of naive T cells. Our data suggest that the accelerated naive CD4 T-cell decline induced by X4 variants is caused mainly by increased death and recruitment to the memory compartment of these cells. (C) 2003 Lippincott Williams Wilkins

Viral infections may cause serious disease unless the adaptive immune system is able to clear the viral agents through its effector arms. Recent identification and functional characterization of subpopulations of human CD8+ T cells has set the stage to study the correlation between the appearance of particular subsets and common viral infections during childhood, i.e., EBV, CMV, varicella-zoster virus (VZV), and the attenuated measles-mumps-rubella (MMR) vaccine strains. In a cohort of 220 healthy children we analyzed lymphocytes and subpopulations of CD4+ and CD8+ T cells. The presence of the cytolytic CD45RA+CD27− subset of CD8+ T cells correlated with prior CMV infection as defined by seroconversion (p < 0.0001). The number of this CD8+ T cell subset remained stable during follow-up over 3 years in 40 children. The CD45RA+CD27− subset of CD8+ T cells first appeared during acute CMV infection and subsequently stabilized at an individual set-point defined by age and immunocompetence. The functional importance of these cells in CMV surveillance was reflected by their increased numbers in immunosuppressed pediatric kidney transplant patients. Preferential expansion of CD8+CD45RA+CD27− cytolytic T cells seems unique for CMV.

To explore aspects of cellular immune responses in the pathogenesis of periodontitis we analyzed phenotype and function of peripheral T cells. Two groups of subjects participated: one group consisted of 10 highly susceptible patients with severe periodontitis (mean age 29 years) and a control group consisted of 10 age, gender and race matched subjects with gingivitis. From all subjects peripheral blood was collected. The results showed that the numbers of CD3+, CD4+ and CD8+ T cells as well as the CD4/CD8 ratio, and the proliferative capacity of T cells, were not different between the two groups of subjects. Also, proportions of naive and memory T cells for both the CD4+ and CD8+ subpopulations were not different. Functional heterogeneity within the CD4+ and CD8+ T cell compartments was determined by intracellular analysis of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) production. On the basis of these latter analyses among CD4+ and CD8+ cells, T helper (Th) 1 or Th2 function and T cytotoxic (Tc) 1 or Tc2 function, respectively, could be deduced. No significant differences in proportions of CD4+ and CD8+ T cells positive for intracellular IFN-gamma or IL-4 were observed between periodontitis patients and gingivitis controls; however a higher level of intracellular IL-4 in CD8+ T cells was seen in periodontitis patients. This might indicate that there is a shift towards a Tc2 function within the CD8+ T cell subpopulation. The current explorative study suggests that further research into the role of CD8+ T cells in the pathogenesis of periodontitis is warranted.

Objective: To evaluate long-term immune reconstitution of children treated with highly active antiretroviral therapy (HAART). Methods: The long-term immunological response to HAART was studied in 71 HIV-1-infected children (aged 1 month to 18 years) in two prospective, open, uncontrolled national multicentre studies. Blood samples were taken before and after HAART was initiated, with a follow-up of 96 weeks, and peripheral CD4 and CD8 T cells plus naive and memory subsets were identified in whole blood samples. Relative cell counts were calculated in relation to the median of the age-specific reference. Results: The absolute CD4 cell count and percentage and the CD4 cell count as a percentage of normal increased significantly (P < 0.001) to medians of 939 × 10 6 cells/I (range, 10-3520), 32% (range, 1-50) and 84% (range, 1-161), respectively, after 48 weeks. This increase was predominantly owing to naive CD4 T cells. There was a correlation between the increase of absolute naive CD4 T cell counts and age. However, when CD4 T cell restoration was studied as percentage of normal values, the inverse correlation between the increase of naive CD4 T cell count and age was not observed. In addition, no difference in immunological reconstitution was observed at any time point between virological responders and non-responders. Conclusions: Normalization of the CD4 cell counts in children treated with HAART is independent of age, indicating that children of all age groups can meet their CD4 T cell production demands. In general, it appears that children restore their CD4 T cell counts better and more rapidly than adults, even in a late stage of HIV-1 infection.

Activation of resting T cells has been proposed to purge the reservoir of HIV-1-infected resting CD4+ T cells. We therefore treated three HIV-1-infected patients on antiretroviral therapy with OKT3, a CD3 monoclonal antibody, and recombinant human IL-2. Here we report the profound and partially long-lasting host responses induced by the OKT3 and IL-2 treatment. OKT3/IL-2 induced a strong but transient release of plasma cytokines and chemokines. The percentage CD4+ and CD8+ cells in the blood expressing the activation marker CD38 transiently increased to almost 100%, and in lymph nodes we "observed" a 10-fold increase in the number of dividing Ki67+ cells and increased numbers of apoptotic cells. Following OKT3/IL-2 treatment, a long-lasting depletion of CD4+ cells in the peripheral blood and lymph nodes occurred, suggesting the physical deletion of these cells. Increases in CD4+T cell numbers during the two year followup period were due mainly to increased memory cell numbers. CD8+ cells were also depleted in the blood, but less severely in lymph nodes, and returned to baseline levels within several weeks.

Objectives: To study the effect of highly suppressive antiretroviral therapy on the slopes of HIV-1 RNA decline in primary compared with chronic HIV-1 infection. Methods: Slopes of HIV-1 RNA decline in plasma were compared before and after the start of highly suppressive antiretroviral therapy from five acutely infected patients who started treatment 2 to 5 weeks following the onset of clinical symptoms. Slopes of decline after the initiation of therapy were also compared with those found in 12 chronically infected individuals on the same therapy. Numbers and percentages of activated CD4 and CD8 T cells at baseline were compared as well. Results: The pre-treatment slopes of HIV-1 RNA decline in the acutely infected individuals increased significantly (P = 0.0001) after the start of anti-retroviral therapy. However, these post-treatment slopes were lower than those found in the chronically infected individuals (P = 0.012). Slopes were inversely correlated (P = 0.012) with baseline HIV-1 RNA. Although the number of CD38+HLA-DR+ CD4 cells was higher in primary infection (P = 0.02), the percentage did not differ between primary and chronic infection. Conclusions: These findings indicate that antiretroviral therapy contributes significantly to the clearance of HIV-1 during primary infection. Based on the mathematical model the less steep RNA slope following the start of treatment in primary infection can be predicted to be the result of lower clearance of productively infected cells and higher burst size per cell per unit time. This may indicate a growing immune response to HIV-1 in this very early stage of infection.

T-cell proliferation is an important in vitro parameter of in vivo immune function and has been used as a prognostic marker of human immunodeficiency virus type 1 (HIV-1) disease progression. The proliferative capacity of T cells in response to various stimuli is commonly determined by a radioactive assay based on incorporation of [3H]thymidine ([3H]TdR) into newly generated DNA. In order to assess techniques for application in laboratories where radioactive facilities are not present, two alternative methods were tested and compared to the [3H]TdR assay as a “gold standard.” As an alternative, T-cell proliferation was measured by flow cytometric assessment of CD38 expression on T cells and by an enzyme-linked immunosorbent assay (ELISA) based on bromo-2′-deoxyuridine (BrdU) incorporation. Peripheral blood mononuclear cells (PBMCs), either in whole blood or Ficoll-Isopaque separated, from a total of 26 HIV-1-positive and 18 HIV-1-negative Dutch individuals were stimulated with CD3 monoclonal antibody (MAb) alone, a combination of CD3 and CD28 MAbs, or phytohemagglutinin. BrdU incorporation after 3 days of stimulation with a combination of CD3 and CD28 MAbs correlated excellently with the [3H]TdR incorporation in both study groups (HIV-1 positives,r= 0.96; HIV-1 negatives,r= 0.83). A significant correlation of absolute numbers of T cells expressing CD38 with [3H]TdR incorporation, both in HIV-1-positive (r= 0.96) and HIV-1-negative (r= 0.84) individuals, was also observed under these conditions. The results of this study indicate that determination of both the number of CD38-positive T cells and BrdU incorporation can be used as alternative techniques to measure the in vitro T-cell proliferative capacity. The measurement of CD38 expression on T cells provides the additional possibility to further characterize the proliferating T-cell subsets for expression of other surface markers.

Lymphocyte proliferation is a widely used technique to assess immune competence. However, the technique is subject to a large degree of variation, some biological and some technical. In this study, the components of variation in whole blood proliferation assays were analysed over time, using both antibody and mitogenic stimulants. The levels of variation within individual samples, between individuals and between groups of individuals over time were examined. A method of transforming the data is proposed which reduces the coefficients of variation to an acceptable level, and which expresses individual results as a standardised count. This method overcomes the problem of different levels of absolute counts, it corrects for time sensitive errors and allows data from multiple laboratories to be pooled.

After viral infection, naive CD8 + T cells become activated and either differentiate into effector cells, which eliminate virus-infected cells, or convert to memory-type T cells, awaiting re-challenge with virus. Here, Dorte Hamann and colleagues propose a model for antigen-induced differentiation of human CD8 + T cells in vivo and discuss its implications for the lineage relation between memory and effector T cells.

Lymphoproliferative responses (LPRs) to recall antigens (Ags) and human immunodeficiency virus type 1 (HIV-1) Gag and frequencies of circulating HIV- 1-specific cytotoxic T lymphocyte precursors (CTLps) were measured in 12 patients undergoing highly active antiretroviral therapy (HAART) after long- standing HIV-1 infection. LPRs to at least 1 recall Ag became detectable or increased in all patients during HAART. No significant LPRs to Gag-p24 were observed, whereas 4 of 8 patients tested presented with Gag-p17-specific LPRs. HIV-1-specific CTLp frequencies became measurable or increased early during therapy in 6 of 10 patients tested and were maintained or decreased thereafter. Increasing HIV-1-specific CTLp frequencies were seen only in association with partial HAART failure in 1 patient. In conclusion, restoration of CD4+ T lymphocyte responsiveness to recall Ags is achieved during HAART. The data provide evidence for limited HIV-1-specific CD4+ memory T cells during advanced HIV-1 infection and suggest that both CD4+ and CD8+ HIV-1-specific T cells are poorly stimulated when viral load is suppressed.

Interferon (IFN)-beta has been shown to favorably alter the disease course of relapsing-remitting multiple sclerosis (RRMS) patients. Although its mode of action is still unclear, there is ample evidence from in vitro studies that IFN-beta directly modulates the function of immune cells. We analyzed here the effects of IFN-beta treatment on immune functions in vivo in a group of 25 RRMS patients who received IFN-beta (8 MIU) on alternate days. At baseline and at 1, 3 and 6 months from the start of the treatment, parameters for differentiation and activation states of both monocytes and T lymphocytes were assessed. A transient increase was seen in plasma (p) interleukin (IL)-10 level whereas pIL-12 (p40) was not affected. A similar change was found in the ability of monocytes to secrete these cytokines in vitro. Notably, patients who in vitro readily responded to IFN-beta with enhanced IL-10 production had the highest pIL-10 levels. Concerning T-cell differentiation, flow cytometric analysis of cytokine production showed that treatment with IFN-beta moderately decreased the mean percentages of CD8pos T cells producing IL-2 and IFN-gamma and CD8neg T cells producing IL-4 (p

Today's antiretroviral combination regimens can induce significant and sustained decreases in human immunodeficiency virus (HIV)-RNA levels, allowing the immune system to recover. To what extent immune reconstitution is possible and what factors determine the outcome have thus far not been resolved. We studied 19 subjects, treated for 2 years with protease inhibitor-containing triple therapy, who had a strong suppression of HIV-RNA levels. CD4+ T-cell numbers increased from medians of 170 to 420 x 106 cells/L, but in a number of subjects T-cell numbers did not further increase after week 72, without having reached normal values. Long-term CD4+ T-cell change was mainly caused by a slow but continuous increase in naive CD4+ T cells (CD45RA+CD62L+) and was predicted by the baseline number of these cells. Our data indicate that long-term immunological recovery is gradual, even during strong suppression of viral replication, not always complete, and dependent on the preexisting level of naive CD4+ T cells.

Background A stable reservoir of latently infected, resting CD4 T cells has been demonstrated in HIV-1-infected patients despite prolonged antiretroviral treatment. This is a major barrier for the eradication of HIV by antiretroviral agents alone. Activation of these cells in the presence of antiretroviral therapy might be a strategy to increase the turnover rate of this reservoir. Methods Three HIV-1-positive patients on potent antiretroviral therapy, in whom plasma viremia had been suppressed to below 5 copies/ml for at least 26 weeks, were treated with a combination of OKT3 (days 1-5) and recombinant human IL-2 (days 2 6). Results The side-effects were fever, headache, nausea, diarrhea, and in one of the patients transient renal failure and seizures. The regimen resulted in profound T cell activation. In one patient plasma HIV-1 RNA transiently increased with a peak at 1500 copies/ml. In the other two patients plasma HIV-1 RNA levels remained below the detection limit, but HIV-1 RNA levels in the lymph nodes increased two- to threefold. All patients developed antibodies against OKT3. Conclusion OKT3/IL-2 resulted in T cell activation and proliferation, and could stimulate HIV replication in patients having achieved prolonged suppression of plasma viremia. OKT3/IL-2 therapy was toxic and rapidly induced antibodies against OKT3.

Background: Current antiretroviral treatment can induce significant and sustained virological and immunological responses in HIV-1-infected persons over at least the short- to mid-term. Objectives: In this study, long-term immune reconstitution was investigated during highly active antiretroviral therapy. Methods: Patients enrolled in the INCAS study in The Netherlands were treated for 102 weeks (range 52-144 weeks) with nevirapine (NVP) + zidovudine (ZDV) (n = 9), didanosine (ddl) + ZDV (n 10), or NVP + ddl + ZDV (n = 10). Memory and naive CD4+ and CD8+ T cells were measured using CD45RA and CD27 monoclonal antibodies (mAb), T-cell function was assayed by CD3 + CD28 mAb stimulation, and plasma HIV-1 RNA load was measured by ultra-direct assay (cut-off

The objective of this retrospective cohort study is to assess the mechanism by which human immunodeficiency virus type 1 (HIV) influences hepatitis C virus (HCV) replication in injecting drug users. Virological (HCV and HIV RNA levels) and immunological (CD4+, CD8+ cell counts, and anti-CD3 reactivity) parameters were determined in 19 HCV seroconverters in sequential samples over a period of 1 to 9 years. Among these subjects, 10 were HIV-seronegative (HIVneg), 4 were HIV-seropositive (HIVpos), and 5 seroconverted for HIV (HIVsc) during the observation period. HCV RNA levels were higher in HIVpos subjects than in HIVneg subjects. In subjects seroconverting for HIV, HCV, RNA levels increased significantly immediately after HIV seroconversion (P 500 cells/microliter (P = 0.001), but not in the population with CD4+ cell counts

The origin of CD4+ T cells reappearing in the blood following antiretroviral therapy in human immunodeficiency virus type-1 (HIV-1) infection is still controversial. Here we show, using mathematical modeling, that redistribution of T cells to the blood can explain the striking correlation between the initial CD4+ and CD8+ memory T-cell repopulation and the observation that 3 weeks after the start of treatment memory CD4+ T- cell numbers reach a plateau. The increase in CD4+ T cells following therapy most likely is a composite of initial redistribution, accompanied by a continuous slow repopulation with newly produced naive T cells.

Objective: To investigate the relationship between exposure to antiretroviral drugs and the initial decline of plasma HIV-1 RNA. Design: Open-label study in antiretroviral-naive HIV-1 infected patients using a quadruple drug regimen [nelfinavir (NFV), saquinavir (SQV), stavudine, and lamivudine]. Methods: The elimination rate constant (k) for HIV-1 clearance was calculated during the first 2 weeks of treatment in 29 patients. Exposure to NFV and SQV was quantified on each study visit. Observed NFV and SQV concentrations were related to those expected in a reference population and a concentration ratio was calculated. The median concentration ratios for NFV and SQV, the baseline CD4+ lymphocyte count and baseline log10 HIV-1 RNA were correlated with k. Results: A significant positive correlation was observed between k and the median NFV (P = 0.001) or SQV concentration ratio (P = 0.016) in univariate analysis. In multivariate analyses, the median NFV concentration ratio remained significantly correlated with k. Conclusions: The variation in the rate of decline of plasma HIV-1 RNA between patients after the initiation of a quadruple drug regimen could be explained by differences in exposure to NFV or SQV. Determination of k could be used to optimise further antiretroviral drug therapy and may be a first tool to assess antiretroviral activities of new or increasing doses of drugs administered in combination regimens. Furthermore, our data suggest that exposure to antiretroviral drugs should be incorporated in mathematical models to describe HIV-1 dynamics in more detail.

BACKGROUND: A substantial number of patients with advanced HIV infection suffer from intractable diarrhoea. The aim of this study was to evaluate whether potent antiretroviral therapy could alleviate such diarrhoea. METHODS: In an open randomized study the effect of the HIV protease inhibitor indinavir in combination with nucleoside analogue reverse transcriptase inhibitors on chronic HIV-related diarrhoea was investigated in 14 late-stage (CD4+ lymphocyte count

Introduction: Regeneration of CD4+ T lymphocytes has been shown to be thymusdependent in bone marrow transplant recipients and after intensive chemotherapy. The rate of CD4+ T cell regeneration is correlated positively with enlargement of the thymus, as shown on radiographs, and higher rates of CD4+ T lymphocyte regeneration were observed in children as compared with adults, consistent with thymic function diminishing with age. We hypothesized that in HIV infected patients CD4+ T cell recovery during highly active antiretroviral therapy (HAART) may also be thymus dependent. Therefore, repopulation of naive (CD45RA+), memory (CD45RO+) and total CD4+ T lymphocytes and total CD8+ T lymphocytes in peripheral blood was assessed in 13 HIV infected children during the initial 3 months of HAART. Results: Significantly higher recovery rates of naive, memory and total CD4+ T cells were observed in children below the age of 3 years as compared with older children. Kinetics of total CD8+ T cells showed no relation to age. Moreover, recovery rates of naive CD4+ T cells in patients below 3 years of age were 10‐40 fold higher as compared with previously reported naive CD4+ T cell recovery rates in adults on HAART. Conclusions: High recovery rates of naive, memory and total CD4+ T cells can be achieved in children below 3 years of age. Changes in CD8 counts did not correlate with age. These results indicate that regeneration of CD4+ T cells during HAART may be a thymus-dependent process.

Objective: HIV-1 RNA levels in peripheral blood are strongly associated with progression to AIDS, CD4+ T-cell decline, or death. Their predictive value is reportedly independent of the predictive value of CD4+ T-cell counts. Because the interrelations between these parameters of HIV-1 infectin are poorly understood, we studied the kinetics and predictive value of serum HIV-1 RNA levels, CD4+ T-cell counts, and T-cell function. Design and methods: HIV RNA levels, CD4+ T-cell counts, and T-cell function were measured from seroconversion to AIDS in 123 homosexual men who seroconverted during a prospective study and were followers over 10 years. Results: Two patterns of median HIV-1 RNA levels were found during infection: a steady-state and a 'U-shaped' curve. Steady-state high RNA levels were related to rapid disease progression. For the U-shaped curve, there were groups with high and low RNA levels related to disease progression. At 1 year after seroconversion, RNA level was the only marker that was strongly predictive. Furthermore, decreasing RNA levels in the first year following seroconversion were related to better prognosis than stable low levels. Low CD4+ T-cell count and T-cell function became predictive of progression to AIDS at 2 and 5 years after seroconversion, respectively. Conclusions: With ongoing infection, the predictive value of low CD4+ T-cell count and T-cell function increases, whereas the predictive value of high HIV-1 RNA level decreases. These findings reflect the observation that infection with HIV progressively leads towards immune deficiency, which in later stages is most predictive of disease progression.

Gag-specific immune responses and changes in HIV-1 RNA levels were evaluated in eight HIV-1-infected persons, in order to assess the immunotherapeutic potential of HIV-1 pl7/p24: Ty virus-like particles (p24-VLP). All treated subjects showed transient and dose-dependent proliferative responses to the Ty-VLP carrier (stimulation index [SI], 2.0-119.5). Three of four individuals who received either 500 or 1000 μg of p24-VLP also showed proliferative responses to pl7 or p24 (SI, 2.0-15.7). In 2 subjects who were treated with either 500 or 1000 μg of p24-VLP, enhanced Gag-specific CTL precursor (CTLp) frequencies were observed after immunization (10- to 14-fold). Both subjects had low baseline Gag-specific CTL activity (

CD4(pos) TH1 T cells are considered to play a central role in a number of human autoimmune diseases such as rheumatoid arthritis (RA) and multiple sclerosis. Experimental treatment protocols aimed at selectively eliminating CD4(pos) T cells thus far have yielded disappointing clinical results. Here we analyzed phenotype and function of circulating T cells in multiple sclerosis patients treated with the chimeric CD4 mAb cM-T412 in a randomized, double-blind, placebo-controlled, magnetic resonance imaging-monitored phase II trial. Treatment resulted in a long-lasting depletion of CD4(pos) T cells but did not affect CD8(pos) T cell numbers. Analysis of CD4(pos) subpopulations showed that unprimed, CD45RA(pos)/R0(neg) lymphocytes were approximately three times more sensitive to the mAb than primed, CD45RA(neg)/R0(pos) T cells. Notably, within the CD45RA(pos) subset, T cells with phenotypic evidence of prior activation, i.e., expressing Fas, were relatively insensitive to cM-T412, compared with Fas(neg) cells. Remarkably, while a decrease in the number of IL-4-producing T helper 2 (TH2)-type cells in the anti-CD4 treated group was observed, numbers of IFN-gamma-producing T helper 1 (TH1)-type cells remained stable, resulting in a significant increase in the TH1/TH2 ratio. Our data show that treatment with depleting CD4 mAb does not eliminate the cells most strongly involved in the disease process, i.e., primed, IFN-gamma-producing TH1-type cells, and may therefore give an explanation for the lack of beneficial clinical effects of depleting CD4 mAb in human chronic autoimmune disease.

In 219 HIV-1-infected men of the Amsterdam cohort we measured CD4+ T cell numbers and in vitro T cell responses to CD3 MoAbs with or without CD28 costimulation and phytohaemagglutinin (PHA). The value of these markers was estimated for disease progression within 4 years. CD28 expression on T cells has been related to T cell responses. CD28 costimulation considerably enhanced T cell reactivity (≈8–10-fold) with lower coefficients of variation compared with reactivity to CD3 MoAb alone (median 5 versus 20). T cell reactivity to CD3 plus CD28 MoAb was decreased during HIV-1 infection and was besides CD4+ T cell numbers the only independent predictor for progression to AIDS. Compared with the group with high CD4+ T cell numbers the relative risk (RR) for the group with intermediate levels was 2.28, with low levels 5.20. In the groups with intermediate and low CD3 plus CD28 responses the RR was 2.04 and 4.16, respectively. The combined RR for both was 4.65 and 21.63. The independence of this marker was confirmed when the group with low CD4+ T cell numbers was subdivided into groups with high, intermediate and low T cell responses. The expansion of CD8+CD28− T cells was already apparent in HIV− homosexual men, but CD8+CD28+ T cells specifically decreased in patients with AIDS. CD28 expression on T cells correlated moderately with T cell responses to CD3 plus CD28 MoAb. T cell reactivity to CD3 MoAb in the presence of CD28 MoAb is a stronger prognostic marker than T cell reactivity to CD3 MoAb alone.

BackgroundCardiovascular disease (CVD) is the leading cause of adult mortality in low-income countries but data on the prevalence of cardiovascular risk factors such as hypertension are scarce, especially in sub-Saharan Africa (SSA). This study aims to assess the prevalence of hypertension and determinants of blood pressure in four SSA populations in rural Nigeria and Kenya, and urban Namibia and Tanzania.Methods and findingsWe performed four cross-sectional household surveys in Kwara State, Nigeria; Nandi district, Kenya; Dar es Salaam, Tanzania and Greater Windhoek, Namibia, between 2009-2011. Representative population-based samples were drawn in Nigeria and Namibia. The Kenya and Tanzania study populations consisted of specific target groups. Within a final sample size of 5,500 households, 9,857 non-pregnant adults were eligible for analysis on hypertension. Of those, 7,568 respondents ≥ 18 years were included. The primary outcome measure was the prevalence of hypertension in each of the populations under study. The age-standardized prevalence of hypertension was 19.3% (95%CI:17.3-21.3) in rural Nigeria, 21.4% (19.8-23.0) in rural Kenya, 23.7% (21.3-26.2) in urban Tanzania, and 38.0% (35.9-40.1) in urban Namibia. In individuals with hypertension, the proportion of grade 2 (≥ 160/100 mmHg) or grade 3 hypertension (≥ 180/110 mmHg) ranged from 29.2% (Namibia) to 43.3% (Nigeria). Control of hypertension ranged from 2.6% in Kenya to 17.8% in Namibia. Obesity prevalence (BMI ≥ 30) ranged from 6.1% (Nigeria) to 17.4% (Tanzania) and together with age and gender, BMI independently predicted blood pressure level in all study populations. Diabetes prevalence ranged from 2.1% (Namibia) to 3.7% (Tanzania).ConclusionHypertension was the most frequently observed risk factor for CVD in both urban and rural communities in SSA and will contribute to the growing burden of CVD in SSA. Low levels of control of hypertension are alarming. Strengthening of health care systems in SSA to contain the emerging epidemic of CVD is urgently needed.

OBJECTIVE To study progression of HIV infection in individuals who are free of AIDS-defining clinical disease with CD4+ cell counts < 200 x 10(6)/l. DESIGN Prospective and nested case-control study. SETTING Amsterdam cohort study on HIV infection, The Netherlands. PARTICIPANTS Prospective study: 148 asymptomatic HIV-infected individuals with < 200 x 10(6)/l CD4+ cells. Nested case-control study: 58 men with AIDS-free follow-up more than 2 years after CD4 count < 200 x 10(6)/l, compared with 63 who progressed to AIDS within 2 years. MAIN OUTCOME MEASURES Progression to AIDS according to the 1987 Centers for Disease Control and Prevention case definition and death. RESULTS Median AIDS-free interval was 22 months, median interval to death 41 months. Presence of syncytium-inducing (SI) HIV variants, HIV p24 antigen, and a low T-cell response after stimulation with phytohaemagglutinin (PHA) were independent predictors of progression to AIDS. Probability of 1 year AIDS-free survival varied between 89 and 38% by the presence or absence of these additional markers. Effect of early treatment could only be detected in men with HIV p24 antigen and SI variants. Case-control analysis showed similar changes over time regarding prognostic markers in both groups although at a lower rate in the AIDS-free men. Eight men remained AIDS-free more than 4 years, SI variants were absent in seven, and all eight were p24-seronegative. CONCLUSIONS HIV-infected individuals can remain disease-free for more than 4 years with very low CD4+ cell counts, provided that they lack other progression markers: SI variants, p24 antigen and a low PHA-induced T-cell reactivity. A beneficiary effect of early treatment may be limited to men with SI variants and/or p24 antigen.

Objective To monitor a patient who presented with symptomatic HIV-1 infection for virological and immunological parameters in relation to the clinical course. Methods Virological studies included determination of frequency of productively HIV-1-infected peripheral blood mononuclear cells (PBMC) and viral RNA load in plasma and p24 antigenaemia. Immunological studies included the analysis of T-cell subsets, the expression of activation markers, CD45RO and CD45RA antigens, the frequency of cells programmed for death, and T-cell function. Results During the first week post onset of primary HIV-1 infection symptoms high plasma titres of p24 and HIV-1 RNA were observed. The number of productively HIV-1-infected PBMC peaked, coinciding with CD4+ T lymphocytopaenia, during week 2 when clinical improvement started. CD8+ T lymphocytosis was observed 10 days post onset of clinical symptoms, the expanded cell population being of the CD8+CD38+, CD8+CD27+ and CD8+CD28-phenotype. CD8+ T lymphocytosis was paralleled by a high percentage of cells undergoing programmed cell death on in vitro culture. In vitro T-cell function was severely depressed during the first 10 days post onset of clinical symptoms. Within about 3 weeks, following resolution of clinical symptoms, phytohaemagglutinin-induced proliferation was restored to normal levels while responses to the CD3 monoclonal antibody only showed a partial restoration. During follow-up, concomitant with the rise of activated CD8+ T cells, p24 antigen levels and viral RNA load in serum as well as the number of HIV-producing PBMC steeply declined after 2 weeks. Conclusion These findings demonstrate HIV-1-induced abnormalities during severe clinical symptoms of primary HIV-1 infection. The subsequent strong immune response, which is believed to be responsible for efficient control of viral replication, appears to precede clinical improvement.

From a cohort study of homosexual men in Amsterdam, 61 human immunodeficiency virus (HIV)-infected men who had remained asymptomatic for at least 7 years were identified. In a nested case control study, these men were compared with 142 men who progressed symptomatic HIV infection (CDC class IV) within 7 years, regarding laboratory markers, sexual behavior, psychologic coping, and drug use. Of the 61 long-term asymptomatic men, 13 had a CD4+ cell count > or = 500/mm3 after 7 years; in 2 of these 13, the CD4+ cell count had not declined during follow-up. Independent of CD4+ cell count, long-term asymptomatic HIV-1 infection was characterized by stable T cell reactivity after stimulation with monoclonal CD3 antibodies, seropositivity for antibodies to HIV core proteins, and the absence of hepatitis B markers. No association with markers of high-risk sex or the recreational use of drugs was found. Long-term asymptomatic men had a slightly lower score regarding the coping behavior active problem-solving; no other associations with coping behaviors were found

An investigation into the prevalence of human papilloma virus (HPV) infection, abnormal cervical cytology and the relationship between HIV- and HPV infection was done in a group of intravenously (IV) and non-IV drug-using prostitutes. From July 1991 through May 1992, hard drug-addicted prostitutes attending a sexually-transmitted-disease (STD) clinic in Amsterdam were recruited. A questionnaire was administered to obtain demographic characteristics, and medical and STD history. Apart from routine STD examination, cervical scrapes for cytology and samples for HPV DNA detection by polymerase chain reaction (PCR) were collected. Some of the women included in this study also participated in HIV studies among drug users. Their data on HIV- and immunologic status could be combined. A total of 121 women entered the study; 25 women were HIV-seropositive, 44 women were HIV-negative, and the HIV status of 52 women was unknown. All 25 HIV-positive women had normal Pap smears, two of the 44 HIV-negative women had a Pap smear III A, and in the HIV-unknown group, two women with Pap III A and one with Pap III B were found. Eight of the 25 (32%) HIV-positive women were HPV DNA-positive, three of the 44 (7%) HIV-negative women and 10/52 (19%) of the HIV-unknown group. Logistic regression analysis showed that in the total group, presence or cervical HPV DNA was associated with HIV infection (order ratio [OR] for HIV-positives 7.8, 95% confidence interval [CI] 1.8 to 34.6) and with diagnosis of condylomata acuminata at entry to the study (OR 7.5, 95% CI 1.5 to 36.5).(ABSTRACT TRUNCATED AT 250 WORDS)

To determine the kinetics of decline of CD4+ lymphocytes in HIV-1-infected asymptomatic homosexual men. CD4+ lymphocytes were enumerated in a cohort of 187 HIV-1-infected initially asymptomatic homosexual men seen at 3-month intervals over 5 years. During follow-up, 45 men progressed to AIDS (excluding cases presenting with Kaposi's sarcoma). Correlation between rate of CD4+ cell decline and presence of a particular HIV-1 biological phenotype was analysed in 43 participants. CD4+ cell counts declined slowly and continuously in HIV-1-seropositive men who remained asymptomatic during follow-up. A biphasic CD4+ cell count decline was observed in the group who developed AIDS: the decline was slow and steady (5.6 x 10(6)/l per month, similar to that observed in the asymptomatic group) until 18 months before AIDS diagnosis, but became three to five times faster thereafter. Rapid CD4+ cell decline was significantly related to syncytium-inducing, fast-replicating HIV-1 isolates; during the period of slow and steady CD4+ cell count decline, non-syncytium-inducing isolates were predominant. At an average of 18 months preceding AIDS diagnosis, a three to fivefold increase in the rate of loss of CD4+ lymphocytes occurs, and may be related to the appearance of a more virulent HIV-1 phenotype

Declining CD4+ T-cell numbers and anti-CD3-induced T-cell responsiveness are prognostic markers for progression of HIV infection. We investigated the effect of long-term (2-year) zidovudine treatment on these immunological markers in a group of nine asymptomatic p24-antigenaemic men, five of whom progressed to AIDS. A group of 10 untreated HIV-infected men, five of whom progressed to AIDS, was studied as a control. At intake, 1 year before the start of treatment, CD4+ T-cell numbers in the groups were not significantly different. However, at that time progressors already exhibited an extremely low anti-CD3-induced T-cell responsiveness compared with non-progressors. In all people T-cell responsiveness and the number of CD4+ T-cells had improved 6 months after the start of zidovudine treatment. However, CD4+ T-cell numbers were not persistently elevated, and restoration of T-cell responsiveness was of only short duration. Our results show that zidovudine treatment in the asymptomatic phase of HIV infection did not result in a sustained improvement in T-cell function. Furthermore, they suggest that differences in clinical course among zidovudine-treated asymptomatics may be caused by heterogeneity of this group with respect to T-cell functional capacity at the start of treatment.

For identification of risk factors for progression of human immunodeficiency virus (HIV) infection, 746 homosexual men participating in a cohort study in Amsterdam, The Netherlands, were studied since October 1984. A total of 234 of these men were HIV antibody-positive at baseline, and 52 seroconverted during follow-up. These 286 individuals were categorized as high- and low-risk for progression to the acquired immunodeficiency syndrome (AIDS) on the basis of the presence or absence of HIV antigenemia, antibody to HIV core antigen, or a number of T helper lymphocytes less than 0.5 x 10(9)/liter during three or more subsequential blood samples. Ninety-six (41%) of the seropositives and 32 (62%) of those who seroconverted remained low-risk throughout the study period. Bivariate analyses revealed that educational level and a history of herpes zoster were associated with a low- and high-risk status, respectively. In multivariate analyses, a history of herpes zoster and a history of sexual intercourse with a person who had AIDS were associated with a more rapid disease progression. While herpes zoster is considered to be a marker of progressive immunodeficiency, a history of having sexual intercourse with a person who had AIDS points to the more virulent properties of HIV in these persons. Because both seropositives and seroconverters who had sexual intercourse with a person with AIDS had a more rapid disease progression, it seems plausible that being infected by a person with AIDS is a risk factor for a relative short incubation period.

In a cohort of 300 HIV-1-infected homosexual men, studied longitudinally, the prognostic value of T-cell proliferative responses for development of AIDS was analyzed. In 15 persons we observed that, at seroconversion, T-cell reactivity to anti-CD3 monoclonal antibody (Mab) and phytohemagglutinin (PHA) was decreased to 20 and 60% of the normal values, respectively. After seroconversion, within 3 months, the response to anti-CD3 Mab and PHA returned to 60 and 80%, respectively, of the normal magnitude and declined thereafter. To investigate whether low T-cell reactivity correlated with progression to AIDS, groups of progressors and nonprogressors were compared. In individuals who progressed to AIDS, already 12 months before diagnosis, responses to anti-CD3 Mab were virtually absent, whereas at that time CD4+ cell numbers and reactivity to horse anti-human lymphocyte serum and PHA were still comparable to values observed for nonprogressors and the asymptomatic population as a whole. In a disease-free survival analysis, low anti-CD3 Mab reactivity predicted progression to AIDS. Our findings demonstrate that low T-cell responsiveness to anti-CD3 Mab is an early marker of progression toward AIDS in HIV-1 infected individuals.

Item does not contain fulltext

Background: HIV-1 infection is characterized by chronic generalized CD8 and CD4 T cell hyperactivation, the biological effect of which is not understood. Objective: To study the relation between chronic immune activation and CD4 T cell depletion in HIV-1 infection. Design: Prospective cohort study among participants of the Amsterdam Cohort Studies on HIV-1 infection and AIDS who have a known seroconversion date (n = 102). Methods: CD4 and CD8 T cell activation marker expression was analysed by FACScan before and after seroconversion (1 and 5 years after seroconversion); T cell proliferation and T cell numbers were also measured. Cox proportional hazard analyses were used to study the predictive value of these parameters for progression to AIDS. Results: Preseroconversion low CD4 T cell numbers or elevated levels of CD4 T cell activation were associated with increased risk for development of AIDS after HIV-1 seroconversion. Progression to AIDS was associated with loss of both CD4 and CD8 naive T cells. The predictive value of CD8 T cell activation was confirmed and, in addition, in the course of infection low CD4 T cell counts and increasing proportions of dividing CD4 T cells, dividing CD8 T cells or elevated CD4 T cell activation marker expression became independent predictors of progression to AIDS. Conclusions: Increased T cell activation has predictive value for HIV-1 disease progression even before seroconversion. These data support the hypothesis that persistent hyperactivation of the immune system may lead to erosion of the naive T cell pool and CD4 T cell depletion. (C) 2003 Lippincott Williams Wilkins

Objective: To determine the influence of age on the regeneration rate of naive and memory T cells in the blood of 45 adults on highly active antiretroviral therapy (HAART). Methods: The age of the patients ranged from 25 to 57 years. Naive cells were defined as CD45RA+CD27+. Cells negative for CD45RA and/or CD27 were considered memory type cells. Results: The recovery rates of naive CD4 and CD8 T cells were similar, were negatively correlated with age and were decreasing 5% and 3.6% per year, respectively. In a multivariate regression analysis, only age was significantly correlated with the naive T cell recovery rates. The recovery rate of memory T cells showed no relation to age. The average regeneration rate of naive CD4 T cells during HAART, i.e., 0.34 x 10(6) cells/l per day, is not lower than regeneration rates in HIV-negative adults following cytotoxic chemotherapy or CD4 monoclonal antibody therapy. Conclusion: These observations suggest that the thymus contributes considerably to the regeneration of naive T cells in adults on HAART, and that the impact of HIV infection on naive T cell production is small, or rapidly reversible. (C) 2002 Lippincott Williams Wilkins

Seasonal influences on immunological parameters in HIV-infected homosexual men: searching for the immunomodulating effects of sunlight.Termorshuizen F, Geskus RB, Roos MT, Coutinho RA, Van Loveren H.National Institute of Public Health and the Environment (RIVM), Laboratory for Pathology and Immunobiology, P.O. Box 1, 3720 BA Bilthoven, The Netherlands.In view of the capacity of ultraviolet radiation (UVR) to induce suppression of various immunological parameters and to enhance the viral replication of HIV, we investigated whether seasonal influences on immunological parameters that are relevant for HIV infection could be identified. As the sunny season is associated with high levels of ambient UVR, a decline of immunological parameters and an increase of the HIV viral load during the summer months might ensue. We analysed the immunological data of the HIV-infected homosexual men who participated in the Amsterdam Cohort Study on HIV infection and AIDS (1984-1996; n = 556). The effect of season on the individual development of various immunological parameters in time was examined by means of a random effects model for repeated measurements. Lower levels in the mean number of CD4+ T cells and the mean CD4+/CD8+ ratio were found during summer and spring, respectively (P = 0.0001/0.0001). For the CD8+ T cells, high mean values were observed both in April and September (P = 0.0001). The highest T-cell reactivity values were found during the summer (P = 0.0001). No effect of season on the viral load was established. The seasonal effect on CD4+ T cells seemed to be more pronounced at a more advanced stage of the HIV infection. It is concluded that the lower CD4+ T-cell counts during summer support the notion that solar UVR may have a suppressive effect on the cellular immunity of HIV-infected persons. However, whether this observation can be attributed to the effect of ambient UVR solely is questionable, as the other immunological parameters follow different seasonal courses and other reports suggest that both internal and environmental factors influence immunological parameters

BACKGROUND: Measuring proliferative responses of T lymphocytes is a simple, reproducible and widely used assay of immune competence. Evidence suggests a role of T cell reactivity in autoimmune diseases. Interferon (IFN)-beta blocks in vitro proliferation of human T cells. OBJECTIVES: To assess (i) the relation between T cell proliferation and disease characteristics of MS patients, (ii) differences in T cell proliferation between subgroups and HC, and (iii) the predictive value of T cell proliferation for efficacy of IFN-beta. METHODS: Proliferative responses were measured in phytohaemagglutinin (PHA), anti-CD2/CD28 and anti-CD3 stimulated whole blood of 189 MS patients and 249 healthy controls (HC). Forty-eight patients started treatment with IFN-beta. Based on EDSS progression, number of relapses and steroid interventions, patients were classified as either clinical responder or nonresponder to IFN-beta. RESULTS: Significant differences between MS subgroups and HC were found in T cell responses upon both PHA stimulation (RR>HC: p=0.001 and SP>HC: p=0.001) and CD2/CD28 stimulation (RR>HC, SP>HC and PP>HC: all p values

Background : The role of T cell subpopulations and their ability to produce immunoregulatory cytokines has been extensively studied in multiple sclerosis (MS). However, the exact mechanisms by which T cells and cytokines contribute to disease activity remain to be clarified. Objectives : To analyze the longitudinal relation between markers of T cell activation and differentiation and disease activity in MS patients. Methods : During a period of 9 months, clinical disease activity was scored, monthly MRI scans were performed, and blood was taken for immune measurements in a group of 13 untreated clinically definite MS patients. Results : Disease activity, as measured by the occurrence of active MRI lesions, is associated with a significant transient decrease in both T cells producing interferon-γ (IFN-γ) and T cells producing interleukin (IL)-4. Conclusions : Our results suggest that MRI-documented disease activity is associated with a transient decrease in circulating cytokine producing T cells, possibly due to the migration of activated T cells into the CNS.

Next to a profound T cell immunodeficiency, HIV-1 infection induces activation and dysfunction of B cells, resulting in hypergammaglobulinemia. Whereas T cell immune reconstitution with potent antiretroviral therapy has been extensively documented, limited data are available on B cell immune reconstitution. We studied the effect of potent antiretroviral therapy on antibody titers to the viral proteins gp120 and p24 and on total IgG concentrations. Three retrospectively chosen groups were studied: a successfully treated group, untreated controls, and subjects with virological failure after several months of successful therapy. In the successfully treated group, the median total IgG concentrations normalized, whereas they remained elevated in the untreated group and rebounded after an initial decline in the therapy failure group. The HIV-1-specific antibody titers declined in the successfully treated group and followed the rebound of the HIV RNA levels in the therapy failure group. With potent antiretroviral therapy the hypergammaglobulinemia normalized whereas HIV-1-specific immune responses were weakened. The weakening of antiviral immunity with therapy may be relevant for current attempts to gain immunological control over the virus through structured treatment interruptions or therapeutic vaccinations.

Item does not contain fulltext

Immunological values for 562 factory workers from Wonji, Ethiopia, a sugar estate 114 km southeast of the capital city, Addis Ababa, Ethiopia, were compared to values for 218 subjects from Akaki, Ethiopia, a suburb of Addis Ababa, for whom partial data were previously published. The following markers were measured: lymphocytes, T cells, B cells, NK cells, CD4+T cells, and CD8+T cells. A more in depth comparison was also made between Akaki and Wonji subjects. For this purpose, various differentiation and activation marker (CD45RA, CD27, HLA-DR, and CD38) expressions on CD4+and CD8+T cells were studied in 60 male, human immunodeficiency virus-negative subjects (30 from each site). Data were also compared with Dutch blood donor control values. The results confirmed that Ethiopians have significantly decreased CD4+T-cell counts and highly activated immune status, independent of the geographic locale studied. They also showed that male subjects from Akaki have significantly higher CD8+T-cell counts, resulting in a proportional increase in each of the CD8+T-cell compartments studied: naı̈ve (CD45RA+CD27+), memory (CD45RA−CD27+), cytotoxic effector (CD45RA+CD27−), memory/effector (CD45RA−CD27−), activated (HLA-DR+CD38+), and resting (HLA-DR−CD38−). No expansion of a specific functional subset was observed. Endemic infection or higher immune activation is thus not a likely cause of the higher CD8 counts in the Akaki subjects. The data confirm and extend earlier observations and suggest that, although most lymphocyte subsets are comparable between the two geographical locales, there are also differences. Thus, care should be taken in extrapolating immunological reference values from one population group to another.

In three subgroups of a clinically and socially well defined group of Dutch homosexual men, the prevalence of human immunodeficiency virus type 1 (HIV-1) sequences in seronegative blood samples was studied using the polymerase chain reaction (PCR). In 19 seronegative partners of seropositive persons, no HIV-1 sequences were found by PCR in either early (1984/1985) or more recent (1987) samples. In 42 seronegative persons selected by their high risk for HIV-1 infection, none harbored HIV-1 sequences in either early (1985/1986) or late (1989) samples. In 15 people who seroconverted for HIV-1, only 2 samples collected 3 months before seroconversion were PCR-positive. These persons were also HIV antigen-positive at this time. These data suggest that a latent infection greater than 6 months does not occur and that the combination of HIV antibody and HIV antigen tests is appropriate and conclusive in most cases of HIV-1 infection.

In response to viral infection, unprimed naive CD8(+), major histocompatibility complex class I-restricted, virus-specific T cells clonally expand and differentiate into memory- and effector-type cells. Changes in CD8(+) subset distribution were studied in 17 subjects with acute human immunodeficiency virus type 1 infection and in 14 subjects with acute Epstein-Barr virus (EBV) infection, with combined CD45RO, CD27, and CD28 monoclonal antibodies. A vast expansion of memory-type CD45RO(+)CD27(+)CD8(+) T cells, with high expression of the cell-cycle marker Ki-67, was observed in both infections. Strikingly, CD45RO(+)CD27(+)CD28(-) cells increased >10-fold in acute viral infection and had high Ki-67 expression. In acute EBV infection, a substantial portion of the expanded T cells were EBV-peptide specific. These cells resided mainly in the CD45RO(+)CD27(+) subpopulation, with most in the CD27(+)CD28(-) subpopulation. Content of perforin expression, as a measure of cytotoxic capacity, was relatively low in the CD27(+)CD28(+) T cells and highest in the CD27(-)CD28(-) subpopulation.

Although anti-retroviral treatment results in improvement of the clinical condition of AIDS patients and interferes with progression to disease in asymptomatic HIV-1 infected persons, evaluation of efficacy of anti-retroviral therapies using clinical endpoints alone is rather difficult. Shift of treatment to earlier asymptomatic stages of HIV-1 infection, especially with the modem potent anti-retroviral drugs and prophylactic treatment for opportunistic infections results in exceedingly long follow-up periods to clinical endpoints. Because of this, markers of progression of HIV-1 infection have to be used as surrogate markers for clinical efficacy. Ideally, these surrogate markers should be both predictive for disease progression in all stages of asymptomatic infection and validated in therapy protocols that use true clinical endpoints in parallel.

ON the basis of encouraging data from two studies in animals,1,2 the manufacturer of the antiretroviral nucleoside analogue zidovudine (formerly azido--thymidine [AZT]) has initiated a placebo-controlled trial to assess the chemoprophylactic efficacy of zidovudine after occupational or nosocomial exposure to the human immunodeficiency virus type 1 (HIV-1).3,4 It is unlikely, however, that this trial will be completed soon, given the relatively low risk of infection through occupational exposure.4 In anticipation of the results of the study, several programs of zidovudine chemoprophylaxis for health care workers who have been occupationally exposed to HIV-1 have been implemented.4 The aftermath of a tragic.