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)

Beta 2-microglobulin (beta 2m) constitutes the common light chain of both the MHC-encoded HLA-ABC molecules and a group of structurally related glycoproteins recognized by antibodies of the first cluster of differentiation (CD1a, CD1b and CD1c). These CD1 antigens appear similar to murine T1 and Qa molecules in terms of structure and tissue distribution, although the question of inter-species homology is controversial. A further group of alloantigens expressed predominantly on T cells has been reported however, with immunogenetic characteristics more closely analogous to the murine T1/Qa system than the CD1 antigens, although their precise identity remains ill-defined. Having previously shown that malignant B cells may express membrane CD1c, we examined leukaemic B-cells corresponding to early lymphoblastic differentiation (null- and common acute lymphoblastic leukaemia) through to the terminal plasma cell stage for the expression of other non-HLA class I beta 2m-associated molecules. It was found that leukaemic B-cells at intermediate/late stages of differentiation, represented by non-Hodgkin's lymphoma (B-NHL) and 'hairy-cell' leukaemia (HCL), had significantly higher beta 2m:HLA-ABC ratios than did the cells from other types of B-cell malignancy. Although leukaemic B cells with a demonstrable non HLA-ABC-associated beta 2m component expressed detectable levels of CD1c, and insignificant levels of CD1a and CD1b, the antigen density was insufficient to account for the excess beta 2m. In vitro stimulation of leukaemic B cells by phorbol ester substantially increased the expression of HLA-ABC and CD1c, but also accentuated further the difference between the expression of these molecules and that of beta 2m. There was no detectable beta 2m other than that associated with HLA-ABC and CD1 on the surface of malignant T cells by contrast. Our findings strongly support the existence, at certain stages of leukaemic B-cell differentiation, of an additional beta 2m component(s) other than that associated with HLA-ABC and CD1.
 ...
PMID:The MHC class I associated beta 2-microglobulin (beta 2m) light chain is expressed in a molar excess over HLA-ABC and CD1 on the membrane of leukaemic B cells but not leukaemic T cells: evidence for further beta 2m-associated molecules. 171 10

The expression of membrane CD1c, as defined by monoclonal antibody L161, was examined on malignant lymphoid cells from 191 cases of chronic lymphoproliferative disease and on eight 'normal' enriched tonsil B-cell extracts. Of 79 cases of chronic lymphocytic leukaemia (CLL) studied, 77 showed low (less than 20% positive cells) CD1c expression whereas 63/71 (89%) cases of B-PLL, HCL and B-NHL showed increased CD1c+ (but not CD1a or CD1b) components. In contrast, malignancies corresponding to terminal stages of B-cell differentiation (immunocytoma and myeloma) generally showed low CD1c expression as did lymphoid cells from 10 cases of post-thymic malignancy. Although there was some correlation between the expression of membrane CD1c and immunoglobulin (SIg) light chain densities (P less than 0.001), it is relevant in diagnostic terms that seven cases of B-NHL with low SIg staining intensities more typically associated with CLL were CD1c+. CD1c expression was not, however, correlated with the presence of CD23 or FMC7 determinants but did show a similar pattern of expression to that previously reported for beta-2 microglobulin. Determination of cellular CD1c by APAAP immunocytochemistry confirmed the presence of higher antigen densities in malignant B-cells at intermediate/late stages of differentiation and this interpretation was further supported by the finding that the majority of phenotypically mature tonsil B-cells were also CD1c+. The determination of CD1c expression by malignant B-cells may therefore be of particular value in the diagnostic differentiation of chronic lymphoproliferative disorders.
 ...
PMID:Diagnostic differentiation of chronic B-cell malignancies using monoclonal antibody L161 (CD1c). 278 56

The CD1 cluster of monoclonal antibodies (MoAbs) CD1a, CD1b, and CD1c, identifies molecules that are differentially expressed on hematopoietic and nonhematopoietic tissues. Our earlier finding that the mantle zone (MZ) but not the germinal center (GC) of normal lymph nodes (LN) is CD1c+, CD1a-, and CD1b- prompted us to further investigate the expression of these molecules on normal, activated, and malignant B cells. We report that blood and spleen contain CD1c+ B cells that account for 49% +/- 20.4% (mean +/- SD) and 50.9% +/- 4.4% of the total B cell population, respectively. CD1a- and CD1b-specific MoAbs are unreactive with both B and T cells; these latter are CD1c- as well. When CD1c+ and CD1c- B cells are activated in vitro, the CD1c molecule is upregulated in the former subset and induced de novo in the latter. Conversely, activated blood T cells remain CD1c-. Neither CD1a nor CD1b molecules are detected on activated T and B lymphocytes. At ultrastructural level, the CD1c+ B cells exhibit distinctive features, namely, condensed chromatin with or without a nucleolus and a unique cluster of cytoplasmic vesicles and organelles; the number of nucleolated cells is higher in the spleen (95%) than in the tonsil (40%) or blood (5%). These findings further confirm the similarity between blood and MZ B cells. The CD1c expression assessed on 27 B-cell chronic lymphocytic leukemias (B-CLL) and 46 B non-Hodgkin's lymphomas (B-NHL) was detected on 41% and 32% of cases, respectively; the latter comprised four follicular and 11 diffuse histotypes. The Burkitt's lymphomas were CD1c-negative. The B-cell neoplasms were all CD1a- and, except for four with a weak cytoplasmic staining, all CD1b- as well. The clear-cut CD1c distribution in normal LN (MZ+, GC-) contrasted with the evidence that some B-NHL cells of GC origin (eg, follicular with predominantly small cleaved cells) were CD1c+. Overall, the finding that CD1c expression is restricted to a fraction of B cells present in lymphoid organs and in peripheral blood indicates that CD1c is a powerful marker for the identification and dissection of B-cell subsets whose functional properties can now be evaluated.
 ...
PMID:CD1c but neither CD1a nor CD1b molecules are expressed on normal, activated, and malignant human B cells: identification of a new B-cell subset. 326 May 23

The association between Rosai-Dorfman Disease (RDD) and cancer was reported for the first time in 1984. However, there are still a small number of reports of this association. We describe a 60-year-old woman who presented with a focal onset motor seizure followed by tonic-clonic generalization and persistent headache. Magnetic Resonance Imaging disclosed an irregular hyperintense lesion in T2 and vasogenic edema in the left parietal region. Immunohistochemical analysis of a biopsy fragment was positive for protein S-100 and CD68 and negative for CD1a, compatible with the diagnosis of RDD. She previously had breast cancer six years earlier and had used tamoxifen for two years and anostrozol for three years after diagnosis of cancer. RDD has been already associated with different cancers, such as Hodgkin's lymphoma, non-Hodgkin's lymphoma, follicular lymphoma, melanoma, adenocarcinoma and small cell lung cancer. As far as we know, this is the first report of an association between breast cancer and RDD.
 ...
PMID:Isolated central nervous system Rosai-Dorfman disease and breast cancer: an unusual presentation. 3029 95