Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024312 (lymphopenia)
 4,859 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Between 1989 and 1996, 4 cases of Pneumocystis carinii pneumonia (PCP) were observed in patients seronegative for the human immunodeficiency virus who were receiving corticosteroid therapy for dermatomyositis in our institution. These cases were considered unusual in light of the short delay of their onset after initiation of immunosuppressive therapy and their fulminant course: 3 of these patients died of PCP occurring during the first month of treatment with prednisone. In all 4 patients lymphopenia was observed before the initiation of corticosteroid treatment and low CD4 and CD8 cell counts were evident at the time of PCP. These observations support the view of an increase in both the severity and incidence of PCP in patients without human immunodeficiency virus infection and question the need for a primary prophylaxis in patients with connective tissue diseases receiving high-dose corticosteroid therapy.
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PMID:Fulminant Pneumocystis carinii pneumonia in 4 patients with dermatomyositis. 922 30

A case of thymoma with associated opportunistic infections, CD4/CD8 T-lymphocyte imbalance, low CD4-positive T-lymphocyte counts and Kaposi's sarcoma (KS) without HIV infection is reported. Cytomegalovirus inclusions were identified in the nuclei of some KS spindle and endothelial cells. It is known that KS has a high prevalence in AIDS patients and has occasionally been associated with other causes of immunosuppression. In previous studies, coexisting KS and thymoma were related to myasthenia gravis, corticosteroid treatment and excess CD8-positive T-lymphocyte counts. More recently an imbalance between CD4 and CD8 positive T lymphocytes has been identified in association with thymoma. The present case suggests that there may be a relationship between thymoma, CD4-positive lymphopenia, and KS.
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PMID:Thymoma associated with CD4+ lymphopenia, cytomegalovirus infection, and Kaposi's sarcoma. 934 30

Eight Japanese hemophiliacs with chronic hepatitis C (CHC) received interferon (IFN) therapy and four of them (50%) responded completely. Non-responders included 3 double-infected patients: 1 with hepatitis B virus (HBV) and 2 with human immunodeficiency virus-1 (HIV-1). In one of the patients with HIV-1 double infection, the absolute number of CD4+ lymphocytes decreased during IFN therapy. These findings suggest that hemophiliac patients with CHC can respond well to IFN therapy, but in patients who are double-infected with HBV and HIV-1, the indication of IFN therapy should be considered seriously.
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PMID:Interferon therapy for Japanese hemophiliacs with chronic hepatitis C. 936 52

We measured numbers of lymphocytes and subsets in seven HIV negative, HCV positive severe haemophilia B patients, before and after substitution was changed from prothrombin complex concentrate to monoclonally purified concentrate. Data were compared with controls and our previous findings in haemophilia A. At baseline, haemophilia B patients did not differ from controls. After two years, T helper cells showed an increase (p = 0.028), while a rise in B cells approached statistical significance (p = 0.063). Haemophilia A patients showed increased numbers of activated non-B lymphocytes (p = 0.003) and lowered numbers of B cells (p = 0.001) at baseline. After two years activated non-B lymphocytes decreased (p = 0.004), as did the CD4/CD8 ratio (p = 0.002), due to increasing numbers of CD8 positive cells (p = 0.087). Our data suggest minor inhibition of the immune system in haemophilia B patients, which recovers after changing therapy to a monoclonally purified product. These findings contrast with the excessive immune stimulation in haemophilia A. The observed differences might be due to the administered concentrates.
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PMID:Differences in immune response between HCV positive, HIV negative haemophilia A and B patients. 945 24

The efficacy of primary prophylactic treatment for opportunistic infections can be estimated in an observational cohort study by adjusting for clinical and laboratory markers of the immunodeficiency (e.g., oral candidiasis, CD4%, lymphocyte cell counts) as time-dependent co-variates (providing that the treatment does not directly alter the markers). However, the CD4 cell count provides an incomplete measure of the protective immune response, and the efficacy of treatment may be underestimated if there is inadequate adjustment for the severity of immunodeficiency. Unlike prophylactic therapies, the efficacy of which remains relatively constant over time, antiretroviral therapy may produce only transient or time-limited benefits. This problem can be minimized by allowing the effect of antiretroviral therapy to vary over time in Cox proportional hazards models (i.e., to allow the antiretroviral therapy coefficient to change over time). Another difficulty is that CD4 cell counts may underestimate the degree of immunodeficiency after prolonged zidovudine (AZT) monotherapy. If post-antiretroviral therapy CD4 cell counts are used to adjust for the stage of immunodeficiency, it may therefore be helpful to adjust for the duration of antiretroviral therapy with the CD4 cell count at the time of starting antiretroviral therapy. It is interesting to consider statistical models of progressive HIV-induced immunodeficiency in the context of the evolution of host immunity. HIV infection results in the loss of the relatively recently evolved adaptive CD4 T cell-mediated immunity to intracellular parasites. The infected host may compensate for this by making greater use of phylogenetically ancient, more innate protective responses. Because these compensatory responses are polymorphic, this results in the appearance of differences between individuals in the immune response to HIV as the disease progresses. Data from the Western Australia HIV Cohort Study support a two-stage model of immunopathology. The first stage of this model involves a loss of mucosal immunity and occurs at a variable CD4 cell count (of between 400 cells/mm3 and zero), and is marked by a loss of cutaneous delayed-type hypersensitivity responses and oral candidiasis, seborrheic dermatitis, and Pneumocystis carinii pneumonia. The second stage of the model involves a loss of systemic immunity and requires profound CD4 T-cell lymphopenia (CD4 cell count <50 cells/mm3), and is marked by infections such as cytomegalovirus and disseminated Mycobacterium avium infection. The influence of HLA type on the risk for such opportunistic infections becomes apparent during this late phase.
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PMID:The Western Australian HIV Cohort Study, Perth, Australia. 958 48

1. This manuscript describes two different strategies to progress from the clinical assessment of patients to the identification of disease-causing mutations. In the first disease, recognition of a metabolic abnormality allowed direct molecular analysis of the causal gene. In contrast, localization of the second disease gene by linkage analysis was critical to implicate a gene with a previously unsuspected disease role. 2. Two sisters with chronic respiratory disease and recurrent infections were identified as the first cases of adult onset immunodeficiency due to adenosine deaminase deficiency. Autosomal recessive inheritance of two mutations in the adenosine deaminase gene was demonstrated. Enzyme replacement therapy improved the patients' immunological and clinical status. 3. Individuals with pulmonary arteriovenous malformations were used to identify families with hereditary haemorrhagic telangiectasia (HHT, Rendu-Osler-Weber Syndrome). Linkage studies mapped the HHT disease gene in some families to chromosome 9, and demonstrated genetic heterogeneity. The chromosome 9 disease interval was refined, and several candidate genes were assessed. Following the first description of disease-segregating mutations, a complete analysis of the endoglin gene (which encodes an endothelial cell transforming growth factor-beta receptor) identified seven novel mutations. Two mutations did not produce mutant mRNA, and disease severity was comparable between families, indicating that HHT results from stoichiometric insufficiency of endoglin. 4. Each study has implications extending beyond the relatively rare disease analysed. The adenosine-deaminase-deficient patients highlight a treatable cause of HIV-negative CD4+ lymphopenia in adults, perhaps accounting for further cases of 'non-HIV AIDS'. The HHT studies have illuminated a novel area of vascular pathophysiology, with potential relevance to further disease states.
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PMID:Glaxo/MRS Young Investigator Medal. Molecular studies on adenosine deaminase deficiency and hereditary haemorrhagic telangiectasia. 961 53

Protease inhibitors are an important new class of agents for the treatment of human immunodeficiency virus (HIV) infection. The purpose of our trial was to determine the feasibility of combining the protease inhibitor saquinavir with a 96-hour continuous intravenous infusion of cyclophosphamide (800 mg/M2), doxorubicin (50 mg/M2, and etoposide (240 mg/M2) (CDE) plus filgrastim in patients with non-Hodgkin's lymphoma associated with HIV infection. The effect of saquinavir on CDE-induced myelosuppression, CD4 lymphopenia, and non-hematologic toxicity was also sought. Twelve patients with HIV-related lymphoma received CDE every 28 or more days. All patients received saquinavir (600mg PO TID), filgrastim and Pneumocystis carinii and fungal prophylaxis. Patients also received either stavudine (n = 2) or both stavudine and didanosine (n = 10). Toxicity was analyzed using the NCI Common Toxicity Criteria for each cycle and the data were compared with the data from our prior study of CDE plus didanosine. An interim analysis was performed after accrual of the first 12 patients in order to assess toxicity. Severe (grade 3 or 4) mucositis occurred in eight of 12 patients (67%) treated with CDE plus saquinavir compared with three of 25 patients (12%) in our prior study treated with CDE without saquinavir (P < 0.001). In logistic regression analysis, saquinavir use was the only factor associated with a significantly greater risk of severe mucositis (relative risk 7.9; P = 0.03). Saquinavir use was not associated with a significant difference in the incidence of febrile neutropenia, prolonged neutropenia, chemotherapy dose reduction, or in the degree of myelosuppression. The decrease in CD4 lymphocytes for patients treated with saquinavir (absolute decrease of 23/microL, or a 26% decrease from baseline) was significantly less than for patients treated without saquinavir in the prior study (absolute decrease of 91/microL, or 42% decrease from baseline; P = 0.05). Four of 10 patients (40%) treated with saquinavir had an increase in CD4 lymphocytes of > or = 10/microL compared with none of 25 patients (0%) treated without saquinavir (P < 0.001). Combination of the protease inhibitor saquinavir with infusional CDE in patients with HIV-associated lymphoma was associated with a significant increase in the incidence of severe mucositis. This finding suggests that saquinavir may alter the metabolism of one of more of the cytotoxic agents in the CDE regimen, and underscores the need for careful investigation regarding the use of the protease inhibitors in patients receiving chemotherapy.
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PMID:Saquinavir enhances the mucosal toxicity of infusional cyclophosphamide, doxorubicin, and etoposide in patients with HIV-associated non-Hodgkin's lymphoma. 964 31

HIV-1 disease is often associated with CD4+ T lymphopenia as well as quantitative reductions in naive CD8+ T cells and cytopenias involving nonlymphoid hemopoietic lineages. Studies in HIV-1-infected humans as well as in animal models of lenti-virus disease indicate that these effects may be secondary to infection and destruction of multilineage and lineage-restricted hemopoietic progenitor cells. To define the stages of T cell differentiation that might be susceptible to HIV-1, we performed flow cytometric analysis of the surface expression of CXCR4 and CCR5 on T cells and their progenitors from fetal tissue, cord blood, SCID-hu Thy/Liv mice, and adult peripheral blood. We found that CXCR4 is expressed at low levels on hemopoietic progenitors in the bone marrow, is highly expressed on immature (CD3-CD4+CD8-) T cell progenitors in the thymus, and then is down-regulated during thymocyte differentiation. As thymocytes leave the thymus and enter the peripheral circulation, the expression of CXCR4 is again up-regulated. In contrast, CCR5 is undetectable on most hemopoietic progenitors in the bone marrow and on intrathymic T progenitor cells. It is up-regulated when thymocytes coexpress CD4 and CD8, then down-regulated either in the thymus (CD4+ cells) or during exit from the thymus (CD8+ cells). These results indicate that discrete, lineage-related populations of T cell progenitors may vary widely in their potential to respond to chemokines and to be infected by HIV-1, and that T lymphoid differentiation is particularly vulnerable to CXCR4-using viruses.
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PMID:CXCR4 and CCR5 expression delineates targets for HIV-1 disruption of T cell differentiation. 975 95

The dynamic basis for T-cell depletion in late-stage HIV-1 disease remains controversial. Using a new, non-radioactive, endogenous labeling technique, we report direct measurements of circulating T-cell kinetics in normal and in HIV-1-infected humans. In healthy, HIV-1-seronegative subjects, CD4+ and CD8+ T cells had half-lives of 87 days and 77 days, respectively, with absolute production rates of 10 CD4+ T cells/microl per day and 6 CD8+ T cells/microl per day. In untreated HIV-1-infected subjects (with a mean CD4 level of 342 cells/microl), the half-life of each subpopulation was less than 1/3 as long as those of healthy, HIV-1-seronegative subjects but was not compensated by an increased absolute production rate of CD4+ T cells. After viral replication was suppressed by highly active antiretroviral therapy for 12 weeks, the production rates of circulating CD4+ and CD8+ T cells were considerably elevated; the kinetic basis of increased CD4 levels was greater production, not a longer half-life, of circulating cells. These direct measurements indicate that CD4+ T-cell lymphopenia is due to both a shortened survival time and a failure to increase the production of circulating CD4+ T cells. Our results focus attention on T-cell production systems in the pathogenesis of HIV-1 disease and the response to antiretroviral therapy.
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PMID:Directly measured kinetics of circulating T lymphocytes in normal and HIV-1-infected humans. 988 35

A key question in understanding the status of the immune system in HIV-1 infection is whether the adult thymus contributes to reconstitution of peripheral T lymphocytes. We analyzed the thymus in adult patients who died of HIV-1 infection. In addition, we studied the clinical course of HIV-1 infection in three patients thymectomized for myasthenia gravis and determined the effect of antiretroviral therapy on CD4(+) T cells. We found that five of seven patients had thymus tissue at autopsy and that all thymuses identified had inflammatory infiltrates surrounding lymphodepleted thymic epithelium. Two of seven patients also had areas of thymopoiesis; one of these patients had peripheral blood CD4(+) T-cell levels of <50/mm3 for 51 months prior to death. Of three thymectomized patients, one rapidly progressed to AIDS, one progressed to AIDS over seven years (normal progressor), whereas the third remains asymptomatic at least seven years after seroconversion. Both latter patients had rises in peripheral blood CD4(+) T cells after antiretroviral therapy. Most patients who died of complications of HIV-1 infection did not have functional thymus tissue, and when present, thymopoiesis did not prevent prolonged lymphopenia. Thymectomy before HIV-1 infection did not preclude either peripheral CD4(+) T-cell rises or clinical responses after antiretroviral therapy.
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PMID:Analysis of the adult thymus in reconstitution of T lymphocytes in HIV-1 infection. 1002 52


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