Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Controversy exists as to whether hematopoietic progenitor cells are infected by human immunodeficiency virus-1 (HIV-1) in vivo. Most studies have focused on patients with acquired immunodeficiency syndrome (AIDS)/AIDS-related complex, and little data are available on asymptomatic patients with well preserved CD4+ T-cell counts. To determine if CD34+ hematopoietic progenitor cells are infected early in the course of HIV-1 disease, we evaluated 10 asymptomatic HIV-1 seropositive (HIV-1+) patients. The CD34+ cell fraction was purified by a two-step procedure consisting of both affinity chromatography and fluorescence-activated cell sorting that resulted in a median purity of over 99%. Using conventional and nested polymerase chain reaction (PCR) assays, we evaluated the presence and frequency of HIV-1 proviral DNA. Both bone marrow mononuclear cells and CD34- cells from all 10 patients were strongly positive for the HIV-1 pol and/or gag gene sequences. In contrast, sorted CD34+ cells from only two of 10 patients were positive, and the number of copies of proviral DNA in these samples was estimated to be from 2 to 5 per 250,000 cells. To test the in vitro functional capacity of CD34+ progenitors, these cells were assayed in both methylcellulose and long-term stromal culture. We found no significant reduction in the number of colony-forming unit-erythroid (CFU-E), burst-forming unit-erythroid (BFU-E), or colony-forming unit-granulocyte macrophage (CFU-GM) colonies, or in the frequency of cobblestone area forming cells from limit dilution analysis in HIV-1+ asymptomatic patients. Pooled methylcellulose colonies generated from CD34+ cells were HIV-1- in nine of 10 samples. All progeny from long-term cultures of CD34+ cells were HIV-1-. We conclude that the CD34+ hematopoietic progenitor compartment is not infected in the majority of asymptomatic HIV-1+ patients, and that these cells may represent a suitable target for strategies designed to protect developing CD4+ T cells from infection.
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PMID:CD34+ progenitor cells from asymptomatic patients are not a major reservoir for human immunodeficiency virus-1. 754 40

Although it is known that impairment of dendritic cells (DC) plays a role in the pathogenesis and immunosuppression of retrovirus-associated diseases, it is not clear whether, or to what extent, these antigen-presenting cells themselves become infected. The realization that the cells can be generated in vitro in larger numbers than can be isolated from circulating blood or bone marrow raised the possibility that they could be used for therapeutic purposes. Therefore, we investigated whether DC generated in vitro from CD34 precursors are susceptible to infection when cocultured with human immunodeficiency virus type 1- or human T-cell leukemia/lymphoma virus-infected cell lines. While there appears to be a remarkable affinity of the viruses for the plasma membranes of the DC, interiorization or budding was not observed in 30 experiments carried out under a variety of conditions.
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PMID:Interaction of human immunodeficiency virus type 1, human T-cell leukemia/lymphoma virus type I (HTLV-I), and HTLV-II with in vitro-generated dendritic cells. 766 81

A 79-year-old woman of Mediterranean ascent suffered from corticosteroid-dependent chronic obstructive lung disease, hypogammaglobulinemia (IgG 1 and 2), decreased CD16 natural killer cell function and non-HIV related CD4 and CD8 lymphopenia. Such immunodeficiency could be either a variant of common variable immunodeficiency or an early stage of the idiopathic CD4 + T lymphocytopenia syndrome. She developed bilateral lesions of Kaposi's sarcoma on the lower extremities resembling the classic European type of the disease. The tumors contained both CD34 + and Factor XIIIa + cells. The HLA-DR5 haplotype was not found. Weekly low intravenous dosages of vinblastine improved the lesions but the patient died from pontic infarction.
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PMID:[Kaposi's disease in a female patient with acquired HIV-negative immunodeficiency]. 783 Dec 65

The present study demonstrates that the C3b receptor CR1 (CD35) and the C3dg/Epstein-Barr virus receptor CR2 (CD21) are expressed by 25% and 70% of normal human thymocytes, respectively. The expression of CR2 extends to both CD1+ and CD1- cells in the thymus. Two subsets of CR2+ thymocytes were defined expressing low and high density of the receptor. The CR2++ subset represented 20% of CR2+ thymocytes and co-expressed the CR1 receptor. CR2++ thymocytes expressed an immature CD1dull, CD3-, CD4dull, CD8-, CD7++ phenotype and included a subpopulation of large cells expressing CD34. Twenty percent of thymocytes expressed the CD21 epitope defined by monoclonal antibody BU32, which is involved in the binding of CD23 to CD21. These observations provide a basis for a role for CD21 in the proliferation and differentiation of thymocytes at early stages of maturation. The functionality of CR1 and CR2 on thymocytes was evidenced by the ability of the receptors to mediate infection of cells with complement-opsonized human immunodeficiency virus (HIV). The results may be relevant to the immunopathogenesis of HIV infection.
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PMID:CR1(CD35) and CR2(CD21) complement C3 receptors are expressed on normal human thymocytes and mediate infection of thymocytes with opsonized human immunodeficiency virus. 795 70

Bone marrow transplantation is characterized by a prolonged period of humoral immunodeficiency in which many patients have abnormal circulating B-cell subsets, and oligoclonal and monoclonal gammapathies. In this study we examine B-cell precursor reconstitution in the post-transplantation marrow. Within 1 month after transplantation there is a marked increase in the percentage of immature B cells (to 80% of marrow lymphocytes), which can persist for more than 1 year. The increase in B-cell precursors is seen in both adults and children and appears to be independent of age. These cells have a normal precursor B-cell surface antigenic phenotype (CD19+, CD10+, CD20 negative to dim) and generally express very little CD34. No monoclonal or oligoclonal immunoglobulin gene rearrangements are detected in these cells, which enables them to be easily distinguishable from common precursor B-cell acute lymphocytic leukemia lymphoblasts.
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PMID:B-cell precursor bone marrow reconstitution after bone marrow transplantation. 804 94

Cell lineage and cell function antigens were studied immunohistochemically in human immunodeficiency virus-associated oral Kaposi's sarcoma to provide insight into tumor pathogenesis. All tumors were composed predominantly of spindle cells that expressed endothelium-associated antigens, CD34 and CD36 (factor VIII-related antigen was expressed by considerably fewer numbers of tumor cells). Infrequently, spindle tumor cells also expressed actin. Factor XIIIa positive spindle and dendritic stromal cells comprised up to 9% of the tumor cell population. Other spindle and dendritic cells expressing macrophage-associated antigen, CD68, accounted for up to 15% of the tumor cells. Mast cells occurred frequently within and around tumors. Leukocyte function antigen (CD18) was expressed by approximately 13% of tumor cells, and its ligand, intercellular adhesion molecule (ICAM), was expressed by some tumor-associated capillaries (which also expressed endothelial leukocyte adhesion molecule, ELAM) and occasional stromal cells. Staining for proliferating cell nuclear antigen was noted in both interstitial and vascular lining cells. All tumors were non-reactive for human Papillomavirus antigen and HIV p24 antigen. Oral KS is a heterogeneous cellular proliferation composed predominantly of endothelial or endothelium-related spindle cells. Other spindle/dendritic (XIIIa-positive and CD68-positive) cells and mast cells are also present and may contribute to tumor development. ICAM and ELAM expression within tumors may assist infiltration of macrophages and other inflammatory cells into these lesions.
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PMID:Human immunodeficiency virus-associated oral Kaposi's sarcoma. A heterogeneous cell population dominated by spindle-shaped endothelial cells. 810 Apr

CD34 is expressed by essentially all human hematopoietic progenitors including cells of the megakaryocyte (MK) lineage. We have previously reported CD4 expression by some human MK (Blood 81:2,664, 1993). To study the role of maturation on CD4 expression by MK, we examined CD34+ bone marrow cells for their expression of CD41 (GPIIb-GPIIIa) and CD4 with specific monoclonal antibody (MoAb)-fluorochrome conjugates and for DNA polyploidization with propidium iodide or 7-aminoactinomycin D (7-AAD). Surprisingly, MK were at least 20-fold more common in the CD34+ progenitor pool (approximately 10%) than in the more mature CD34+ population (approximately 0.5%) of low density bone marrow cells. CD4 expression correlated with markers of immaturity in that CD4 was enriched among CD34+ cells, and the proportion of CD4+ MK declined with increasing ploidy. Almost all CD34+ polyploid ( > or = 8N) cells were CD4+. Despite these correlations with immaturity, CD34+CD4+ MK precursors were unable to produce MK colony-forming units (CFU-MK) when cultured under conditions that supported the growth of CFU-MK from CD34+CD4- MK lineage cells. MK became polyploid before the loss of either CD34 or CD4 expression. The presence of CD4 on these cells correlates with the onset of endomitotic reduplication and is associated with the loss of the ability of these cells to undergo normal mitotic division. The role of CD4 on immature MK as a differentiation antigen and/or receptor for the human immunodeficiency virus (HIV)-1 virus remains to be determined.
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PMID:Development of human megakaryocytes: I. Hematopoietic progenitors (CD34+ bone marrow cells) are enriched with megakaryocytes expressing CD4. 860 24

Flow cytometry was used to assess CD4 expression in 62 consecutive bone marrow specimens from patients with a variety of clinical conditions. Using a lysed-whole-blood technique for labeling with monoclonal antibodies, two populations of CD4+ cells were identified within the lymphocyte/blast-cell fraction in 58 (94%) of these specimens. These consisted of (1) a population of T helper cells with high density expression of CD4 and (2) a second population of cells with low-density expression of CD4, which ranged from 1% to 36% of the gated cells. This latter population was present regardless of age, sex, or clinical condition including 21 of 21 specimens (100%) categorized as unremarkable bone marrows both morphologically and by flow cytometry and in four of four patients (100%) with human immunodeficiency virus-type 1 (HIV-1) infection. Coexpression of the erythroid lineage marker, glycophorin A, with the majority of cells in this second population was demonstrated in all 11 randomly selected samples using two-color flow cytometric analysis. These cells also expressed low levels of the myeloid markers, CD13 and CD33, but CD34 expression could not be demonstrated. These results provide evidence for expression of CD4 on cells of erythroid lineage in human marrow, and offer a potential mechanism for direct infection of erythroid precursor cells and deranged erythropoiesis in patients with HIV-1 infection.
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PMID:CD4 Expression by erythroid precursor cells in human bone marrow. 863 Mar 88

The susceptibility of highly purified human CD34+ cells to monocytotropic (Ba-L) and lymphotropic (A018-post) strains of human immunodeficiency virus-1 (HIV-1) was examined. Liquid cultures initiated with fresh immunomagnetically purified CD34+ cells using the K6.1 CD34 monoclonal antibody (MoAb) (K6.1/CD34+) were positive for HIV expression 2 weeks after exposure to HIV-1 Ba-L. These cells were initially greater than 90% CD34+ and had undetectable monocyte contamination by flow-cytometric staining and side-scatter analyses, respectively, and undetectable T-cell contamination by CD3 polymerase chain reaction (PCR) analysis. However, secondary CD34+ liquid cultures reselected from the primary liquid cultures 24 hours after HIV exposure by panning with the ICH3 CD34 MoAb (ICH3/CD34+) and maintained for an additional 14 days were negative for HIV expression. The ICH3-unbound cells were positive for both spliced and unspliced HIV RNA when exposed to HIV-1 Ba-L, and were DNA PCR positive when exposed to either monocytotropic or lymphotropic HIV-1. To further test that CD34+ cells were not infectible by HIV-1, we exposed K6.1/CD34+ cells continuously to HIV-1 in a culture system capable of maintaining and expanding primitive CD34+ cells. HIV-exposed K6.1/CD34+ cells proliferated and expanded as efficiently as uninfected cultures. However, when reselected magnetically using the K6.1 CD34 MoAb after expansion for 7 days, bound K6.1/CD34+ cells were again negative for HIV-1 expression, whereas unbound cells were positive for HIV-1 expression. These findings suggest that a sequential CD34+ cell-selection process, in which the two selections are separated by a brief culture period, can yield a population of CD34+ cells that are not infected with HIV-1. This process may be useful in the design of stem or progenitor cell-based transplantation therapies for HIV infection.
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PMID:Exposure of human CD34+ cells to human immunodeficiency virus type 1 does not influence their expansion and proliferation of hematopoietic progenitors in vitro. 870 67

We conducted a clinical trial to determine the feasibility of growth factor mobilization of CD34+ progenitor cells in human immunodeficiency virus type 1 (HIV-1)-infected individuals. Eight asymptomatic, HIV-1-infected adults (median CD4+ T-cell count, 415 cells/microL), received 480 micrograms/d of granulocyte colony-stimulating factor (G-CSF) for 6 days without evidence of viral activation. Despite concerns that HIV-1 might inhibit hematopoiesis, CD34+ cells were successfully mobilized to the periphery of all donors, independent of the baseline CD4+ T-cell count, and the status of antiretroviral therapy. Leukapheresis was performed on day 6, and yielded a median of 194 x 10(6) CD34+ cells per leukapheresis (n = 7). CD34-enriched cells from the leukapheresis were predominantly myeloid-committed, but between 0.2% and 1.7% were primitive CD34+/CD38- progenitors. A median of 21.7% of the mobilized CD34+ cells were dimly positive for CD4. Consequently, CD34(+)-enriched cells were purified on the cell sorter (mean purity, 97.7% +/- 2.4%; n = 7), and examined for HIV-1 DNA. Purified CD34+ cells from two of seven donors were polymerase chain reaction (PCR)-positive for HIV-1, but only from one of three samples from each donor. We conclude that G-CSF can safely mobilize CD34+ progenitor cells in HIV-1-infected subjects, and that these cells are suitable for consideration in gene-transfer strategies.
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PMID:Mobilization of CD34+ progenitor cells by granulocyte colony-stimulating factor in human immunodeficiency virus type 1-infected adults. 889 97


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