Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06126 (CD1a)
 2,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A detailed immunologic study of three cases of sinus histiocytosis with massive lymphadenopathy (SHML) was performed to better characterize this rare disorder. One patient had prominent cervical lymphadenopathy that regressed spontaneously, whereas the other two patients had persistent cervical lymphadenopathy and recurrent infections. The first patient was otherwise healthy and had normal immunologic studies. One of the latter patients had a relative increase in blood B cells, a decreased level of serum immunoglobulin A (IgA), decreased blood lymphocyte mitogenic responses to multiple mitogens (37-42% of controls), and cutaneous anergy. The other patient with persistent disease also had a relative increase in blood B cells, polyclonal hypergammaglobulinemia, and circulating immune complexes, as well as decreased blood T cells and markedly decreased blood lymphocyte responses to mitogens (12-37% of controls). Immunohistochemical stains of the lymph nodes of the three patients revealed a characteristic phenotype for the sinus histiocytes: S-100 protein, 3/3; CD14 (Leu M3) 3/3; CD11c (Leu M5), 1/1; CD71 (OKT9), 3/3; CD4 (Leu 3a), 2/3; CD1a (OKT6), 1/3; alpha-1-antitrypsin, 3/3; alpha-1-antichymotrypsin, 3/3; CD35 (C3b), 1/1; CD11b (Mo1), 0/3; CD15 (Leu M1), 0/3; HLA-DR, 0/3; and lysozyme, 0/3. This phenotype suggests that the cells of SHML have features of both the Langerhans/interdigitating cell and mononuclear phagocyte lineages. Emperipolesis by the histiocytes of B cells, T cells, and natural killer cells was demonstrated by a double-staining technique. Our findings indicate that patients with SHML may have a variably expressed immunodeficiency that predisposes them to recurrent infections.
 ...
PMID:Sinus histiocytosis with massive lymphadenopathy: a spectrum of disease associated with immune dysfunction. 171 75

Human epidermal Langerhans cells play an important role in the immunoregulation of the skin. We measured the numbers of CD(3+)-, CD(8+)-, CD1a(+)-, HLADR(+)-, IL2R(+)-, CD(4+)- and CD68 positive cells in the skin of 8 asymptomatic HIV-infected Persons, 3 Patients with AIDS and 11 healthy volunteers by suction blister technique. Our results indicate increased numbers of CD1a+ cells and increased numbers of CD4+ cells in the epidermis in asymptomatic HIV-infection. At the same time CD68+ cells are decreased already in an early stage of HIV-Infection. The number of CD1a/CD4+ cells is related to the degree of immunodeficiency. This fact might be caused by the activation of MPS.
 ...
PMID:[Lymphocytes, Langerhans cells and CD68-positive monocytes/macrophages in the skin of HIV-infected patients and normal controls]. 172 11

We have investigated the features and distribution of accessory cells (ACs) and the relationship of these cells to each other and to lymphocytes in the epithelium and lamina propria of oral hairy leukoplakia (HL), with the objective of better defining the differentiation and mutual interactions of immune-response cells within HL as a preliminary step to understanding the onset and significance of this lesion during human immunodeficiency virus (HIV) infection. Twenty-four HIV-infected patients with HL, two asymptomatic HIV-positive subjects, and three HIV-negative subjects were studied by immunohistochemistry; five HIV-positive patients with HL and three asymptomatic HIV-positive subjects were studied by electron microscopy. In both the epithelium and the lamina propria of HL, we found cells with the immunohistochemical and ultrastructural features of variably differentiated ACs; differences were found between the epithelium and lamina propria. In the lamina propria, ACs were characterized by dendritic shape, multiple contacts with lymphocytes, expression of CD1a antigen, and ultrastructural features of fully differentiated ACs. Conversely, in the epithelium ACs showed bluntly dendritic shape, low expression of CD1a, absent expression of HLA-DR, constant expression of CD11c and CD14 antigens, only occasional contacts with lymphocytes, and ultrastructural features of variably, but always incompletely, differentiated cells of monocyte-dendritic lineage. Seventy-nanometer wide intracisternal particles, closely resembling A particles described in retroviral infections, were found in the intraepithelial ACs in two patients with HL. The defective differentiation of ACs in the epithelium of HL--possibly influenced by the perturbation of the epithelial microenvironment induced by Epstein-Barr virus, and following the direct HIV infection of these cells--and the exceptional finding of close contacts with lymphocytes suggest that the lesional epithelium of HL may constitute a pathway for the entry of foreign antigens which circumvent monitoring by ACs and can induce immune tolerance. The impairment of the local immune response in HL may contribute to the development of full blown, systemic immunodeficiency.
 ...
PMID:Morphology and membrane antigens of nonlymphoid accessory cells in oral hairy leukoplakia. 239 34

Langerhans cells (LC) are dendritic epidermal antigen-presenting cells expressing the surface molecule CD4, which renders them theoretical cellular targets for direct infection by the human immunodeficiency virus (HIV). To date, somewhat conflicting results have been reported concerning the in vivo infection of LC by HIV as well as the numerical alteration of these cells in the course of HIV infection. In the present work we studied clinically normal skin of a group of 44 HIV-1-seropositive patients classified according to the Centers for Disease Control (CDC) stages II (n = 14), III (n = 9), and IV (n = 21). Monoclonal antibodies (MAb) to HIV p18, p24, and gp120 and to HLA-DR and CD1a antigens (specific for LC) were applied on frozen skin sections using an amplification biotin-streptavidin-fluorescein technique. The MAb to HIV p18 cross-reacted with a cytoplasmic antigen of epidermal basal keratinocytes also present on HIV-seronegative skin specimens. No other reactivity was observed with any of the three anti-HIV MAb. The quantitative study showed that no significant correlations could be established between the number of LC (evaluated independently by HLA-DR and CD1a antigens) and the number of peripheral blood CD4+ve lymphocytes or the CDC disease stage. These results cast some doubt on the previously reported in vivo infection and numerical decrease in LC in HIV infection. The precise involvement of LC in HIV infection awaits further investigation.
 ...
PMID:Immunohistochemical study of normal skin of HIV-1-infected patients shows no evidence of infection of epidermal Langerhans cells by HIV. 247 43

Some infants infected with human immunodeficiency virus type 1 (HIV-1) rapidly develop a fatal disease characterized by a severe lymphopenia. To explain the immune dysfunction, we proposed a mechanism by which a nongeneration of CD4+ T cells is caused by HIV-1 infection of thymic cells. To examine this hypothesis, we infected primary triple-negative (TN; phenotypically CD3- CD4- CD8-), CD1a- TN, or CD1a+ TN thymic cell subsets. Our data indicate that by flow cytometry, TN, CD1a- TN, and CD1a+ TN cells remain CD4 negative throughout the culture period. We demonstrated that TN and CD1a+ TN thymic cell subsets are susceptible to HIV-1 as is the entire thymic cell population, whereas CD1a- TN cells are not. A limited number of infected TN cells are expressing HIV-1 but the level of transcription is very high in permissive cells, as detected by in situ hybridization. We then performed blocking experiments on TN cells to examine the mechanism of HIV-1 entry into these cells. CD4 (OKT4a) monoclonal antibody blocks their infection. Finally, infection experiments on two subpopulations of TN cells (CD2+ CD7+ and CD2- CD7-) indicate that infected TN cells may correspond to both immature thymocytes and thymic dendritic cells. These data are of particular interest since infection of thymic stromal cells might result in an impairment of T-cell differentiation, which may explain a nongeneration of functional CD4+ T-cell population in the thymus. This phenomenon may play a role in AIDS pathogenesis, in particular in infants born from seropositive mothers.
 ...
PMID:Two subpopulations of human triple-negative thymic cells are susceptible to infection by human immunodeficiency virus type 1 in vitro. 751 58

The epidermal Langerhans' cells are dendritic cells of the skin capable of triggering cutaneous immune responses. They possess the membrane antigens required to this effect: class II histocompatibility antigen, CD1a and CD4; the latter acts as receptor for the human immunodeficiency virus. The skin is the organ primarily affected by Kaposi's sarcoma (KS). In epidemic KS, the local immunologic conditions of the skin are little known. We therefore studied 12 patients with AIDS-associated KS, evaluating the density and phenotypic expression in KS-affected and unaffected skin of the following antigens: CD1a, HLA-DR, CD4 in dendritic epidermal cells and dermis, and CD3, CD4 and CD8 in cells of the inflammatory infiltrate, using monoclonal antibodies applied to frozen sections with the avidin-biotin-peroxidase technique. Langerhans' cells in the AIDS-KS skin lesions were found to be decreased in number. This decrease was even more pronounced in the case of cells expressing HLA-DR antigen. A number of them were also revealed with CD4. The tumour lymphocytic infiltrate was almost exclusively composed of CD3+ CD8+ phenotype lymphocytes. The dermis also revealed CD4+ dendritic cells. The basal keratinocytes focally expressed HLA-DR. These phenotypical alterations of the Langerhans' cells and the local immunological imbalance observed may contribute to the growth and continuity of the KS lesions.
 ...
PMID:Langerhans' cells and lymphocytic infiltrate in AIDS-associated Kaposi's sarcoma. An immunohistochemical study. 752 Nov 2

Dendritic cells (DC) are specialized antigen-presenting leukocytes that are responsible for the activation of naive as well as memory T lymphocytes. If infected by human immunodeficiency virus (HIV), DC may transfer virus to CD4+ lymphocytes. However, the question of whether DC are infected in vivo is controversial. As HIV infection is more active in secondary lymphoid organs than in blood, infection of splenic DC isolated from HIV-seropositive patients was investigated. Splenic DC were first enriched and characterized by flow cytometry from HIV- donors. After direct isolation, they were negative for monocyte and T- and B-lymphocyte markers, negative for CD1a, but positive for major histocompatibility complex class II and CD4. After in vitro maturation, major histocompatibility complex class II expression increased, while CD4 expression was lost. Extensive purification from the spleens of seven HIV+ patients was performed by fluorescence-activated cell sorting. The frequency of cells harboring HIV DNA in purified populations was quantified by limiting-dilution PCR. Directly isolated DC (average, 1/3,000; range, 1/720 to 1/18,000) were in each patient 10 to 100 times less infected than CD4+ T lymphocytes (average, 1/52; range, 1/17 to 1/190). On average, 1/1,450 (1/320 to 1/6,100) unseparated mononuclear splenocytes (containing 5% CD4+ lymphocytes) harbored HIV DNA. In conclusion, in these HIV+ patient spleens, DC seem to be infected, but HIV-DNA positive CD4+ T lymphocytes accounted for the vast majority of infected mononuclear splenocytes.
 ...
PMID:Infection frequency of dendritic cells and CD4+ T lymphocytes in spleens of human immunodeficiency virus-positive patients. 760 39

Langerhans cells (LC) belong to the dendritic cell family and represent the principal antigen presenting cells populating squamous epithelia. We have reported the presence of human immunodeficiency virus Type 1 (HIV-1) proviral DNA and RNA in purified LC from the epidermis of seropositive patients. The aim of this study was to quantify HIV-1 proviral DNA in LC of infected patients using a competitive polymerase chain reaction (PCR) assay. Bulk epidermal cell (EC) suspensions were obtained from the skin of nine AIDS patients and six seronegative subjects. Purified LC and LC-depleted EC were prepared by immunomagnetic separation using an anti-CD1a monoclonal antibody. LC preparations did not contain T cells, as assessed by reverse transcription PCR analysis of the T cell receptor beta-chain gene (C region). In addition, no CD14+ cells could be detected in LC fractions by immunostaining of cytospin preparations. To quantify HIV-1 DNA, a new competitive PCR system was devised using SK145/150 as primers (gag) and a competitor plasmid DNA with a modified sequence (209 instead of 142 bp). The number of HIV-1 DNA copies found in the LC of AIDS patients ranged from 107 to 3,645/10(5) LC. In contrast, LC-depleted EC from the same subjects were all negative. The results indicate that in AIDS patients the frequency of infected LC is comparable to that reported for peripheral blood CD4+ T cells.
 ...
PMID:Quantitation by competitive PCR of HIV-1 proviral DNA in epidermal Langerhans cells of HIV-infected patients. 810 64

Langerhans cells (LC) are antigen-presenting cells which are found in areas at risk of inoculation by the human immunodeficiency virus (HIV). LC were shown to be sensitive to in vitro infection by HIV1. They could be generated in vitro by culturing CD34+ haematopoietic progenitors with GM-CSF+TNF alpha. In this study, we tested the sensitivity to HIV1 infection of in vitro generated LC throughout their differentiation and we investigated the effect of such an infection on in vitro differentiation. Phenotypic controls were performed using FACS analysis on day 6 for the presence of a CD1a+ cell population, and differentiation was assessed by transmission electron microscopy on day 13 for the presence of Birbeck granules. CD34+ cells were purified from cord blood mononuclear cells by magnetic separation. Cell suspensions were infected with either a T-lymphotropic, syncytium-inducing isolate (HXB2) or a macrophage-tropic, non-syncytium-inducing isolate (Ba-L). Viral particle release was measured by p24 antigen production in the culture supernatant. A high level of p24 production was noted on day 13 of postinfection only when infection was carried out with Ba-L isolate on cells generated after 6 days in culture with GM/CSF+TNF alpha. No infection of CD34+ progenitor cells was obtained either with Ba-L isolate or HXB2. The sensitivity of Langerhans cell/dendritic cell (LC/DC) precursors to NSI isolate (Ba-L) seemed to coincide with the early stage of differentiation (CD1a antigen appearance). The infection did not alter the differentiation of in vitro generated LC, which presented their specific ultrastructural marker of epidermal environment, i.e. Birbeck granules from day 15 of the culture as compared to control culture. These results highlight the HIV infectibility of a differentiated population of LC/DC generated in vitro from CD34+ progenitors.
 ...
PMID:In vitro HIV1 infection of CD34+ progenitor-derived dendritic/Langerhans cells at different stages of their differentiation in the presence of GM-CSF/TNF alpha. 890 26

We report the case of a boy with low expression of HLA class I molecules on peripheral blood mononuclear cells, which is associated with immunodeficiency. The patient, who had a Marfan-like phenotype, had chronic deep skin ulcers and sinobronchiectasis. Immunohistologic examination of the ulcerated skin showed a dense perivascular infiltrate composed of normal mature lymphocytes and macrophages. All cells in the infiltrate showed an apparently normal expression of HLA class I molecules, but intraepidermal dendritic Langerhans' cells were negative for CD1a, an antigen that is a highly specific marker for these cells and is abundantly expressed in some self-healing forms of cutaneous lesions. It is therefore speculated that a defective expression of CD1a molecules can contribute to the chronic persistence of deep skin ulcers, which have already been reported in association with defective expression of HLA class I molecules.
 ...
PMID:Defective expression of HLA class I and CD1a molecules in boy with Marfan-like phenotype and deep skin ulcers. 891 93


1 2 3 4 5 Next >>