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

We describe the clinical, ultrastructural, and immunophenotypical characteristics of four cases of an unusual type of T cell leukemia. Clinical features included high WBC, ranging from 26-148 x 10(9)/liter, bone marrow infiltration, splenomegaly, and lymphadenopathy. Skin involvement was not documented at presentation, but it was seen as a terminal event in one patient with a pattern of dermal lymphocytic infiltration different from that usually seen in Sezary syndrome. By ultrastructural analysis, the circulating lymphoid cells were indistinguishable from small Sezary cells in two cases, resembled large Sezary cells in one case, and consisted of a mixture of small Sezary cells and prolymphocytes in the remaining case. The cells from all cases had a mature T cell phenotype, TdT-, CD1a-, CD2+/-, CD3+, CD5+. In addition, the cells were either CD8+, CD4- or CD8+, CD4+ or CD4-, CD8-; and, in only one case, the findings were similar to those of Sezary syndrome cells: CD4+, CD8-, CD7-, BE-2+. In the latter case, serological and immunological assays were positive for HTLV-I while these were negative in two other patients investigated. The features of these patients suggest that Sezary cell leukemia is a distinct clinico-pathological entity although the alternative diagnosis of adult T cell leukemia/lymphoma could not be excluded in the HTLV-I+ case. Sezary cell leukemia appears to be resistant to current chemotherapy regimens and is associated with an aggressive clinical course and short survival.
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PMID:Sezary cell-like leukemia: a distinct type of mature T cell malignancy. 236 82

The immunophenotypes of the HLA-DR-positive leucocyte populations in normal human skin were studied using an extensive panel of monoclonal antibodies, which included antibodies from the Third International Leucocyte Differentiation Antigen Workshop (3rd LDAW). Langerhans' cells (LC) in the epidermis stained with antibodies from CD15c, Groups 10, 12a, 12b and 15, of the myeloid panel and from CD39 of the B-cell panel. However, LC did not react with CD14 antibodies or 63D3, which are frequently used to stain tissue macrophages. In addition to epidermal LC (26 cells/linear mm) a significant population of CD1a-positive cells was identified in the papillary dermis (7 cells/linear mm of overlying epidermis). The dermal HLA-DR-positive leucocytes consisted of three cell populations. The most numerous cell type stained with antibodies to monocytes/macrophages. There were fewer, though substantial, numbers of T lymphocytes (mainly CD7-negative) and the least numerous was the population of CD1a-positive cells. The CD1a-positive cells and the population of dermal cells that stain with monocyte/macrophage markers are both potential antigen-presenting cells for the skin-associated immune system.
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PMID:HLA-DR-positive leucocyte subpopulations in human skin include dendritic cells, macrophages, and CD7-negative T cells. 306 20

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.
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PMID:Two subpopulations of human triple-negative thymic cells are susceptible to infection by human immunodeficiency virus type 1 in vitro. 751 58

Three colour flow cytometric analysis has been used to analyze the expression of a series of surface antigens on human thymic and peripheral T-cell populations. CD4, CD8 and CD3 were used to divide the populations into the conventional major categories, and the distribution of CD1a, CD2, CD7, CD34, CD44, class I MHC and class II MHC was then determined. Some characteristics of 'single positive' (CD4+8- and CD4-8+) T-lineage cells were unexpected. Amongst thymocytes, some 'immature single positives' were delineated as larger sized cells lacking cell surface CD3 and expressing low levels of class I MHC; however, in contrast with murine thymocytes, these were all CD4+8-, rather than being predominantly CD4-8+. Amongst peripheral T cells, a small proportion of CD7- cells were detected, within both the CD4+8-3+ and the CD4-8+3+ categories. Finally, in contrast to previous conclusions, CD1a was expressed at high levels on mature (CD4+8-3+ and CD4-8+3+) human thymocytes, although in agreement with previous reports it was absent from peripheral T cells. CD1a is therefore a useful marker of post-selection, post-thymic T-cell maturation.
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PMID:Surface antigens of human thymocyte populations defined by CD3, CD4 and CD8 expression: CD1a is expressed by mature thymocytes but not peripheral T cells. 768 45

To date no hematopoietic progenitors of dendritic Langerhans' cells (DLC), which represent an highly efficient class of antigen presenting cells, have been identified or the cytokines they elaborate have been defined. Here we describe an acute leukemia patient whose blasts (90-96% in peripheral blood and bone marrow) had a phenotype consistent with putative progenitors of DLC. The patient was treated with ara-C and VP-16 but did not achieve remission. The blasts had lobulated nuclei, no cytoplasmic vacuolation or Auer rods and were weakly positive for acid phosphatase and non-specific esterase and negative for PAS, granzyme A, dipeptidyl aminopeptidase IV, ATPase/ADPase and lysozyme production. The blasts were positive for CD1a, CD4, CD16, CD35, HLADR, HLADQ, CD11b, CD11c, CD14, CD33, CD34, CD11a, CD71, CD19, CD25, IL-2R beta and negative for CD2, CD7, CD8, CD10, CD22, CD56, CD57, surface or cytoplasmic CD3, TCR delta and TCR beta, HTLV-1p19 and P-glycoprotein. On liquid culture with or without 5 x 10(-9) M 12-O-tetradecanoylphorbol-13-acetate (TPA) for 3 days, the blasts formed aggregates of proliferating and elongating cells on the wall of the flasks with a decline in CD34, numerous dendritic processes appeared on the cells and there was strong positivity for ATPase/ADPase, but no other changes in phenotype. No macrophages were observed, indicating derivation from separate DLCs. Cytogenetic analysis showed chromosomal abnormalities and electron microscopy showed Birbeck granules. Southern blotting of DNA showed rearrangement of one allele for both JH and TCR beta but no HTLV-1 related sequences. Culture supernatants from blasts cultured with or without TPA showed the production of large amounts of IL-8, IL-6, TNF-alpha, MIP-1 alpha, IL-10 and interferon gamma and modest amounts of IL-1 alpha, GM-CSF and stem cell factor. The presence not only of CD1a, HLADR, HLADQ and many other characteristics including Birbeck granules, but also differentiation along the lines of DLC with appearance of dendritic processes on the cells and expression of ATPase/ADPase activity, indicate that the leukemic blasts in our patient represented a leukemic counterpart of normal progenitors of DLC and the leukemia a new entity which could possibly be classified as AML-M8. Lastly, many pro-inflammatory cytokines produced by DLC could contribute to inflammation and IL-10 to immunosuppression.
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PMID:Phenotype, genotype and cytokine production in acute leukemia involving progenitors of dendritic Langerhans' cells. 791 55

The upper airway is the first site of exposure to inhaled antigens and the site of initiation of mucosal immunity to certain antigens; however, the intraepithelial lymphoid populations of this region have not been well characterized. We studied 6-mu frozen tissue sections from tonsils, adenoids, and nasal mucosae using immunohistochemistry and a panel of antibodies to mononuclear antigens to determine whether nasal mucosa contained distinctive populations of mononuclear cells. Intraepithelial lymphocytes (IELs) of nasal mucosa were CD3+, CD8+, and mainly CD5+. Tonsil and adenoid both showed diffuse CD8+ IELs; clusters of CD4+ IELs were associated with B cells within the crypt epithelium. All nasal IELs were uniformly negative for Leu8 (homing receptor analog of Mel14). Scattered Leu8-positive cells were present within tonsil and adenoid crypt epithelium only. Nasal IELs rarely expressed HML1 and were often CD7-, whereas the majority of tonsillar and adenoidal IELs were HML1+ and variably CD7+. In nasal mucosa and in deep submucosa of tonsil and adenoid, 80 to 90% of T cell receptor expression was of alpha/beta type. There was a concentration of gamma/delta T cell receptor-positive cells in intraepithelial and subepithelial zones of tonsil and adenoid, with areas of up to 30% gamma/delta T cell receptor positivity. A population of intraepithelial dendritic cells was identified in all three tissues expressing mononuclear phagocyte system antigens CD14 and KiM1P, but lacking CD1a. Virtually no B cells and no organized subepithelial lymphoid tissue were identified in nasal mucosa. Nasal mucosal lymphoid tissue seems to differ from that of endodermally derived mucosae, tonsil, and adenoids to share similarities with both mucosa-associated lymphoid tissue and peripheral lymph nodes.
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PMID:Immunohistochemical characterization of intraepithelial and subepithelial mononuclear cells of the upper airways. 823 57

We describe the case of a patient with peripheral gamma/delta T-cell lymphoma (T-ML) with hepatosplenomegaly, generalized lymphadenopathy, and bone marrow involvement. A 44-year-old man had lymphoma, which became clinically apparent 2 months after the onset of myositis and insulin-dependent diabetes mellitus. A cervical lymph node biopsy specimen showed diffuse infiltration by large neoplastic cells with vascular proliferation. The neoplastic cells expressed the T-cell receptor (TCR)delta chain detected by TCR delta 1 and delta-TCS1, CD3, CD30, CD45RO, and epithelial membrane antigen, but not the TCR beta chain detected by beta F1, CD1a, CD2, CD4, CD5, CD7, CD8, CD25, HLA-DR, and terminal deoxynucleotidyl transferase. The cells had a clonal rearrangement of TCR gamma chain gene and a germ-line configuration of immunoglobulin heavy chain gene and TCR beta chain gene. Despite chemotherapy, the patient died of refractory lymphoma 4 months after diagnosis. Examination at autopsy revealed that the main hepatic and splenic neoplastic infiltration sites were the portal area and white pulp, respectively. Our patient differed from those with gamma/delta T-ML with hepatosplenic involvement reported previously with respect to the hepatic and splenic neoplastic infiltration patterns and the presence of lymphadenopathy.
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PMID:Gamma/delta T-cell lymphoma with hepatosplenomegaly: report of a case. 836 90

Two different subsets of CD4+,CD8+ T lymphocytes have been identified in peripheral blood collected from normal subjects and from patients with different diseases. The subpopulations differed in the degree of CD4 and CD8 antigen expression. Hence, it was possible to distinguish by cytofluorimetric analysis cells with a low (dim) or with a high (bright) fluorescence intensity after the staining with anti-CD4 or anti-CD8 mAbs. CD4+dim,CD8+bright lymphocytes were found in patients with EBV-infectious mononucleosis and were present for less than a month. CD4+bright,CD8+dim T cells were observed in neoplastic patients as well as in healthy subjects and were continuously present in similar percentages over a long period of time (at the moment, about 3 years). Both the subpopulations expressed CD2, CD3, CD5 antigens and had an alpha beta-TCR, but did not express CD1a or CD7. Only CD4+dim,CD8+bright cells expressed HLA-DR antigen and the activation marker CD38, while only CD4+bright,CD8+dim lymphocytes expressed CD56 and CD57 molecules. The hypothesis may be put forward that these two subsets represent an effort of the immune system to cope with different requirements, i.e., of viral or neoplastic origin, while it is not clear the meaning of these cells in healthy subjects.
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PMID:Cytofluorimetric identification of two populations of double positive (CD4+,CD8+) T lymphocytes in human peripheral blood. 846 Oct 16

The immunophenotype of 304 adult lymphoblastic leukemias (> 18 years) diagnosed on the basis of the FAB criteria was determined at the time of diagnosis using a panel of monoclonal antibodies. The series comprised cases diagnosed and immunophenotyped in 43 Italian centers (GIMEMA Cooperative Group) between April 1988 and June 1991. The immunophenotypic characterization consisted of two consecutive steps. The initial screening was based on the reactivity for TdT, HLA-Dr, CD7, CD10, CD13, CD19, CD24, CD33 and CD41. According to the results obtained, the second level of investigation assessed the positivity for intra cytoplasmic (Cy) Ig, CD1a, CD2, CD3, CD4, CD5, CD8 and CD20. Based on the hierarchical expression of the different B- and T-cell related antigens, each case was assigned to a given differentiation stage. B-lineage ALL were classified in five subgroups (B0-B4) and T-lineage ALL in four subgroups (T0-T3). Cases in which the blasts were lymphoid according to the FAB criteria, but expressed myeloid antigens in association with B- and T-lymphoid markers were defined as hybrid leukemias. As expected, CD10+ cases (B2-B3) were the most frequent within the B-lineage ALL (83.2% of cases). CyIg+ (B3) accounted for about 20% of CD10+ ALL. Twenty eight cases (13.4%) were at a pre-cALL stage (B0-B1) and of these, 8 (3.8% of the total series) were positive only for TdT and HLA-Dr (B0). Intermediate and mature thymic phenotypes (T2-T3) were predominant within the T-ALL (67.2%) groups. Five cases, were positive only for TdT and CD7 (CD5+), and classified as T0. 9.2% of cases fulfilled the definition of hybrid leukemia, largely in view of the co-expression of B-lymphoid and myeloid markers.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Immunophenotype of acute lymphoblastic leukemia cells: the experience of the Italian Cooperative Group (Gimema). 847 81

It has been observed that immunological reactivity of neonatal leukocytes is diminished. It seems to result from lymphocytes immaturity. In the present study we have evaluated the phenotype of cord blood lymphocytes with the use of flow cytometry. In neonates we have observed the increase in the absolute number of CD1a and CD7 positive lymphocytes as well as CD2, CD3, CD4, CD8, CD16, CD19 and CD20 positive, while number of CD57 positive cells was significantly decreased. The ratios of CD4/CD8 and T/B lymphocytes were similar to the corresponding ratios observed in adults. Our results have shown the presence of immature lymphocyte population as well quantitative depletion of subpopulation of CD57 cells, what may pose an increased risk of infection in neonates. Nevertheless, increased number of T and B lymphocytes with mature phenotype along with normal ratio of lymphocyte subpopulations and increased number of CD16 positive cells (NK cells), may explain phenomenon of good health among majority of newborns.
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PMID:[Flow cytometric analysis of cord blood lymphocytes]. 964 Aug 62


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