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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of carbohydrates in the immunogenicity of human immunodeficiency virus type 1 (HIV-1) glycoproteins (gp160 and gp120) remains poorly understood. We have analyzed the specificity and neutralizing capacity of antibodies raised against native gp160 or against gp160 deglycosylated by either endo F-N glycanase, neuraminidase, or alpha-mannosidase. Rabbits immunized with these immunogens produced antibodies that recognized recombinant gp160 (rgp160) from HIV-1 in a radioimmunoassay and in an enzyme-linked immunosorbent assay. Antibodies elicited by the different forms of deglycosylated gp160 were analyzed for their reactivity against a panel of synthetic peptides. Compared with anti-native gp160 antisera, serum reactivity to most peptides remained unchanged, or it could increase (peptide P41) or decrease. Only antibodies raised against mannosidase-treated gp160 failed to react with a synthetic peptide (peptide P29) within the V3 loop of gp120. Rabbits immunized with desialylated rgp160 generated antibodies which recognized not only rgp160 from HIV-1 but also rgp140 from HIV-2 at high titers. Although all antisera produced against glycosylated or deglycosylated rgp160 could prevent HIV-1 binding to CD4-positive cells in vitro, only antibodies raised against native or desialylated gp160 neutralized HIV-1 infectivity and inhibited syncytium formation between HIV-1-infected cells and noninfected CD4-positive cells, whereas antibodies raised against alpha-mannosidase-treated gp160 inhibited neither virus replication nor syncytium formation. These findings indicate that the carbohydrate moieties of gp160 can modulate the specificity and the protective efficiency of the antibody response to the molecule.
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PMID:Influence of carbohydrate moieties on the immunogenicity of human immunodeficiency virus type 1 recombinant gp160. 134 97

To assess the hypothesis that the human immunodeficiency virus (HIV) might mimic major histocompatibility complex (MHC) allodeterminants and interact with T-cell receptors (TCRs) of alloreactive T-cells, we have done a preliminary analysis of the range of alpha beta TCR gene products in 16 HIV-1-seropositive individuals with normal CD4 counts and in 16 healthy HIV-1-negative controls. Using a panel of monoclonal antibodies with a two-colour direct immunofluorescence method, we found a significant increase in the expression of the V beta 5.3 subfamily in the HIV-positive patient group compared with controls (p less than 0.01). Selected increase in expression of V beta sequences has been described in various autoimmune conditions and our findings raise the possibility that the immunopathological damage from HIV infection may be due to the induction of autoreactivity. If HIV does mimic MHC II, the normal immune response to the virus could represent an autoimmune process similar to graft-versus-host disease.
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PMID:T-cell receptor variable gene products and early HIV-1 infection. 135 71

Thrombocytopenia is a known complication of human immunodeficiency virus Type-1 (HIV-1) infection, and more data need to be collected on its frequency, severity, and clinical sequelae. We determined the frequency of thrombocytopenia and its relationship to other HIV infection characteristics from a review of records of 1004 HIV-infected patients attending two outpatient clinics in Washington, D.C. The self-reported sources of HIV-1 exposure were male homosexual activity (68%), bisexual activity (10%), heterosexual activity (6%), and intravenous drug use (15%). Fifty-nine percent of the individuals were white, 37% were black and 94% were male. Fifteen percent had AIDS. Thrombocytopenia occurred more frequently in subjects with AIDS (21.2%) than in HIV-infected individuals who did not fit clinical criteria for AIDS (9.2%) (p less than 0.001). Patients with few CD4-positive cells and an advanced stage of disease were more likely to have low platelet counts: 30% with an absolute CD4 cell count lower than 200/mm3 vs 8% with CD4 counts between 200 and 500 (p less than 0.00001), and 18.5% with Stage IV disease compared to 7.6% in Stage II (p less than 0.001) had platelet counts less than 150,000/mm3. Thrombocytopenia was more frequent in white males and older subjects. Although subjects infected by heterosexual exposure had a lower frequency of thrombocytopenia, intravenous drug users and homosexual men exhibited similar frequencies of thrombocytopenia. Of all subjects with platelet counts less than 50,000/mm3, 40% reported bleeding and 1 died of an intracranial hemorrhage. Thrombocytopenia occurs frequently in HIV-infected people, primarily in those with AIDS, low CD4 cell numbers, and advanced stages of diseases.
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PMID:Epidemiology of thrombocytopenia in HIV infection. 850 Jun 8

In a retrospective analysis of data from 35 cases with malignant lymphoma from a cohort of 2017 HIV-infected patients, the stage of HIV-disease, the CD4 counts at the time of diagnosis, and the use of antineoplastic agents or radiotherapy were correlated with outcome. 6 patients had Hodgkin's lymphoma (HL) and 29 non-Hodgkin-lymphoma (NHL). 11 of these lymphomas were classified according to the international working formulation (IWF) as high grade (H, I and J, respectively) and 8 as intermediate grade (G). 10 could not be classified. 22 patients with NHL had stage IV disease according to the Ann Arbor classification, all of whom had manifestations at extranodular sites. 23 patients with NHL were treated with multiagent chemotherapy (18 with m-BACOD or CHOP, 5 patients with various other regimens) and four of them had additional radiotherapy. One patient received radiotherapy only. Two of 24 treated patients showed complete and five a partial response. Median survival of patients without treatment (all of them in poor general condition at the time of diagnosis) was 1.8 months and treated patients survived a median of 5 months. The pretreatment CD4 count was the most important predictor of survival. Patients with prior Aids-diagnosis showed a tendency towards shorter survival. The observed remission rate indicates that HL in HIV-infected patients is better treatable than HIV-associated NHL. However, the overall outcome of HL in our patients was clearly less favorable compared to the course of HL usually seen in patients without HIV infection. The proportion of patients with HL among all patients with malignant lymphoma and HIV disease was unexpectedly larger in our cohort compared to others. Therefore, a possible association of HL and HIV infection, as addressed by several other authors, needs further clarification.
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PMID:[HIV-associated malignant lymphomas]. 134 90

Broncho-alveolar lavage was performed to assess the degree of pulmonary lymphocytic alveolitis in 32 asymptomatic patients who were infected with the Human Immunodeficiency Virus (VIH). The patients were stages II and III of the CDC classification and the aim of the study was to determine the frequency, nature and prognostic role of the findings. 62.5% of the subjects (20/32) presented with a lymphocytic alveolitis which consisted predominantly of CD8 lymphocyte (64.3 +/- 3.5%), in the absence of an opportunistic infection or broncho-pulmonary tumours. Two sub-populations of alveolar CD8 were shown at comparable levels, a) sub-population CD8+D44+ (22.1 +/- 5%), in whom we showed the possession of cytotoxic activity in particular specific for VIH; b) sub-population CD8+CD57+ (19.6 +/- 3%) which we have shown to be capable in vitro of inhibiting the effector phase of cytotoxic activity of CD8+D44+ alveolar cells specific for VIH. In this group of 32 patients the occurrence of an alveolitis was not correlated with the usual prognostic factors of infection by VIH measured simultaneously with broncho-alveolar lavage (the level of CD4+ blood lymphocytes, and the beta 2-plasma microglobulins and the presence of p24 antigenaemia). In addition the level of CD4 lymphocytes supperior to 400/mm3 and of beta 2-microglobulins less then 3 mg/l whether a lymphocytic alveolitis was there or not confirmed the relatively poorly developed state of the VIH infection in these asymptomatic patients. Also the occurrence of a lymphocytic alveolitis did not seem to be linked to progression of the disease in the group of patients studied.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Lymphocytic alveolitis in the early stages of HIV infection: correlation with biological and prognostic factors]. 134 63

The 1st case definition for AIDS was developed by the Centers for Disease Control (CDC) in 1982. WHO adopted CDC definitions for use in some countries and also developed a clinical case definition where HIV serology tests were not feasible. A multivariate analysis of data of Brazilian AIDS patients with positive HIV serology provided the basis for the Caracas definition in 1989 and it subsequent revision. The accuracy of these 3 clinical definitions was evaluated to see their predictive value in an advanced stage of AIDS. The records of 224 HIV-positive adults were reviewed in 1990. Scores were assigned to various symptoms. 80% of men and 20% of women with a median age of 33 years; 1/4 were white and 2/3 were black. 1/3 were homosexuals and 1.2 were iv drug users. 139 were asymptomatic (CDC stage I-II) and 85 were symptomatic (CDC stage IV). 58 patients had total CD4 cell counts of over 500 x 1 million/1; 91 had 200-500 x 1 million/l; and 70 had 200 x 1 million/1. 48 were taking zidovudine and Pneumocytis carinii drugs. The sensitivities of the WHO, original Caracas definition, and revised Caracas definition were 40%, 67%. and 60%, respectively, with 99-100% specificities and positive predictive values of 97-100%. The mean CD4 cell counts for the WHO, original and revised Caracas definitions were 184, 160, and 158 x 1 million/1, respectively, compared with 199 x 1 million/1 of patients with CDC stage IV disease. The predictive values of the 3 definitions for CD4 cell counts 200 x 1 million/1 reached 62%, 73%, and 71% vs. only 59% for CDC stage IV patients. The combination of stage IV symptoms or a CD4 cell count 200 x 1 million/1 produced sensitivities of 31%, 53%, and 47%, respectively, with 100% specificity and positive predictive values. The definitions were highly specific, but only moderately sensitive for advanced AIDS; the Caracas definitions were more sensitive than the WHO definition.
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PMID:Diagnostic accuracy of three clinical case definitions for advanced HIV disease. 134 46

To investigate its use as a marker of disease severity, serum soluble CD4 (sCD4) was measured by ELISA in patients with human immunodeficiency virus (HIV) infection. Levels of sCD4 were higher in patients than in controls (P less than .001) but did not increase with disease severity. sCD4 release per CD4 lymphocyte showed a linear increase with disease severity and performed as well as beta 2-microglobulin, a widely used marker. To study the role of sCD4 in the pathogenesis of HIV infection, an ELISA to detect sCD4 complexed with glycoprotein 120 (gp120) HIV envelope protein was developed. Preformed sCD4-gp120 complexes were not detectable in patient serum, but addition of recombinant gp120 showed that circulating sCD4 is capable of binding HIV envelope proteins. This study indicates that the sCD4-to-CD4 lymphocyte ratio increases linearly with disease severity and may be a useful marker of CD4 lymphocyte damage. In addition, serum sCD4 can bind viral particles, which may have implications for the use of recombinant sCD4 as a therapy in HIV infection.
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PMID:Naturally occurring soluble CD4 in patients with human immunodeficiency virus infection. 134 32

Children born to women known to be infected with human immunodeficiency virus type 1 (HIV-1) before delivery were followed prospectively from birth in nineteen European centres. This analysis, encompassing the period end-December, 1984, to beginning-August, 1991, focuses on risk factors for mother-to-child transmission of HIV-1 infection. Rate of vertical transmission, based on 721 children born to 701 mothers more than 18 months before the time of analysis, was 14.4% (95% Cl 12.0-17.1%). Transmission was associated with maternal p24-antigenaemia and a CD4 count of less than 700/microliters. In a multivariate analysis, odds ratios of transmission were: 2.25 (95% Cl 0.97-5.23) in breastfed children vs never-breastfed children; 3.80 (1.62-8.91) in children born before 34 weeks' gestation; and 0.56 (0.30-1.04) in children delivered by caesarean section. Transmission was higher with vaginal deliveries in which episiotomy, scalp electrodes, forceps, or vacuum extractors were used, but only in centres where these procedures were not routine. On the basis of these results, HIV-infected women contemplating pregnancy should be counselled according to their immunological findings and, if they have p24-antigenaemia or a low CD4 count, warned of an increased risk of viral transmission. Caesarean deliveries may have a protective effect, although it is premature to recommend routine operative delivery. The mechanism for the higher infection rate in children born before 34 weeks' gestation is unclear, but could reflect inadequate passive or active immunity at that age, combined with substantial transmission during labour or delivery. The balance of evidence suggests that mothers with established infection can transmit HIV infection through breastmilk, although the relative importance of this route remains to be defined.
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PMID:Risk factors for mother-to-child transmission of HIV-1. 135 93

In AIDS a complementary interface between the HIV virus and the CD4 molecule of the T4 lymphocyte suggest a possible cause of immune self-recognition. Because of this complementarity, an anti-idiotypic immune response to the CD4 attachment area of HIV should result in an autoimmune reaction to CD4 positive lymphocytes. Experimental demonstration of such an immune recognition model by autoreactive lymphocytes is presented and a hypothetical immune response unit is suggested.
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PMID:AIDS--an autoimmune model. 134 51

With the advent of standard flow cytometric methods using two-colour fluorescence on samples of whole blood, it is possible to establish the ranges of CD3, CD4 and CD8 T lymphocyte subsets in the routine laboratory, and also to assist the definition of HIV-1-related deviations from these normal values. In 676 HIV-1-seronegative individuals the lymphocyte subset percentages and absolute counts were determined. The samples taken mostly in the morning. The groups included heterosexual controls, people with various clotting disorders but without lymphocyte abnormalities as well as seronegative homosexual men as the appropriate controls for the HIV-1-infected groups. The stability of CD4% and CD8% values was demonstrated throughout life, and in children CD4 values less than 25% could be regarded as abnormal. The absolute counts of all T cell subsets decreased from birth until the age of 10 years. In adolescents and adults the absolute numbers (mean +/- s.d.) of lymphocytes, CD3, CD4 and CD8 cells were 1.90 +/- 0.55, 1.45 +/- 0.46, 0.83 +/- 0.29 and 0.56 +/- 0.23 x 10(9)/l, respectively. In patients with haemophilia A and B the mean values did not differ significantly. In homosexual men higher CD8 levels were seen compared with heterosexual men and 27% had an inverted CD4/CD8 ratio but mostly without CD4 lymphopenia (CD4 less than 0.4 x 10(9)/l). However, some healthy uninfected people were 'physiologically' lymphopenic without having inverted CD4/CD8 ratios. When the variations 'within persons' were studied longitudinally over a 5-year period, the absolute CD4 counts tended to be fixed at different levels. As a marked contrast, over 60% of asymptomatic HIV-1+ patients exhibited low CD4 counts less than 0.4 x 10(9)/l together with inverted CD4/CD8 ratios. Such combined changes among the heterosexual and HIV-1-seronegative homosexual groups were as rare as 1.4% and 3%, respectively. For this reason, when the lymphocyte tests show less than 0.4 x 10(9)/l CD4 count and a CD4/CD8 ratio of less than unity, the individuals need to be investigated further for chronicity of this disorder, the signs of viral infections such as HIV-1 and other causes of immunodeficiency.
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PMID:Laboratory control values for CD4 and CD8 T lymphocytes. Implications for HIV-1 diagnosis. 134 72


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