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)

Bacterial superantigens (Sag) are potent activators of T cells. This T-cell activation has been described as an MHC class II dependent phenomenon. We have observed that human thymocytes depleted of MHC class II positive cells are still able to proliferate in response to the staphylococcal enterotoxin A (SEA). This proliferation was clearly inhibited by the addition of monoclonal antibodies directed against the CD1a molecule. In contrast, monoclonal antibodies directed against the CD1b and CD1c molecules have no effect on the Sag-induced activation of the CD2 (+) MHC class II (-) thymocytes. We next examined the ability of the CD1a molecule to transmit transmembrane signals. Results obtained indicate that CD1a ligation on these thymocytes induced tyrosine phosphorylation of the p56(lck) tyrosine kinase. Signal transduction via CD1a is further confirmed by the observation of a significant intracellular calcium flux (Ca(i)(++)) in thymocytes following CD1a engagement. These data demonstrate that CD1a ligation induces a signal transduction pathway which has a potential role in the bacterial superantigen-induced activation of human CD2 (+) MHC class II (-) thymocytes.
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PMID:Role of the CD1a molecule in the superantigen-induced activation of MHC class II negative human thymocytes. 1077 45

Cytologic, immunologic, and cytogenetic studies were performed on the blast cells of a newborn with Down syndrome and transient myeloproliferative disease. This hematologic disorder is uncommon, and occurs primarily in infants with Down syndrome. This boy presented with a high white blood cell count and a high percentage of blast cells, without anemia or thrombocytopenia. Chromosome analysis showed a constitutional trisomy 21 without any other clonal abnormality. A three-color flow cytometric analysis was performed and revealed two different CD45 dim, CD34(+), CD117(+), CD56(+) immature subpopulations: the normal immature myeloid precursor and an immature blast cell population that expressed CD41, CD42, CD61, CD36, CD13, CD1a, and CD2. We postulate that this population could be the leukemic precursor involved in the acute megakaryoblastic leukemia frequently observed in children with Down syndrome.
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PMID:Immunophenotype of a transient myeloproliferative disorder in a newborn with trisomy 21. 1079 50

We have attempted to improve retrovirus-mediated gene transfer efficacy into hematopoietic progenitor cells (HPCs) without causing them to lose their lymphoid potential. Highly purified CD34(+) cells on CH-296 fibronectin fragments have been transduced with three different cytokine combinations. Murine CD2 was used as a marker gene. Transgene expression was assayed by FACS analysis shortly after transduction of CD34(+) cells and after long-term culture (LTC) extended by differentiation of various lymphoid lineages: NK cells, B cells, and dendritic cells. Compared with the historical cytokine mix, i.e., SCF (stem cell factor) + IL-3 (interleukin 3) + IL-6, the combination SCF + FL (Flt-3 ligand) + M-GDF (megakaryocyte growth and differentiation factor) + IL-3 significantly improved the total number of viable cells and CD34(+) cells after transduction and the long term-cultured progenitors after 6 weeks. In addition, the combination of SCF + FL + M-GDF + IL-3 maintained more efficiently the lymphoid potential of the progeny of transduced long term-cultured CD34(+) cells, as attested by the significantly higher number of CD56(+), CD19(+), and CD1a(+) cells recovered when FL and M-GDF were added to SCF + IL-3. Thus, even though additional improvements may still be needed in transduction of HPCs, these conditions were adopted for a clinical trial of gene therapy for X-linked severe combined immunodeficiency.
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PMID:Optimization of retroviral gene transfer protocol to maintain the lymphoid potential of progenitor cells. 1117 65

At the ISAC 2000 Congress, the Clinical Cytometry Society organized a meeting of international experts to reach consensus on the minimum number of antibodies required for a full evaluation of hematologic and lymphoid neoplasias. A questionnaire was distributed prior to the meeting to numerous experts from US and European institutions and 13 responses were received. At the meeting, 25 individuals, including most of those who returned responses, participated in the discussions and voted on the issues presented. In chronic lymphoproliferative disorders (CLD), 9 antibodies (anti-CD5, CD19, kappa, lambda, CD3, CD20, CD23, CD10, and CD45) were deemed essential for initial evaluation by 75% of the participants. There was near unanimity that additional markers (selected from CD22, FMC7, CD11c, CD103, CD38, CD25, CD79b and heavy chains for B-cell disorders, and CD4, CD7, CD8, CD2, CD56, CD16, TCRa/b, and TCRg/d for T-cell disorders) would be needed to fully characterize CLD, although not every marker would be useful in all cases. Tissue lymphomas were believed to be similar to CLD, needing a minimum of 12--16 markers. However, for some cases, CD30, bcl-2, TdT, CD71, CD1a, and CD34 were cited as useful by the participants. Markers mentioned for plasma cell disorders included kappa, lambda, CD38, CD45, CD56, CD19, CD20, CD138, and heavy chains. Of 17 voting participants, 16 agreed that between 5 to 8 markers would be essential reagents for plasma cell disorders. For acute leukemia (AL), 10 markers (CD10, CD19, CD13, CD33, CD34, CD45, CD7, CD14, CD3, and HLADR) were considered essential by 75% of participants for initial characterization of the leukemia lineage. Most (>75%) agreed that at least one more B (CD20, CD22, CD79a, IgM), T (CD1a, CD2, CD4, CD5, CD8), myeloid (CD11b, CD15, CD64, CD117, myeloperoxidase), erythroid (CD36, CD71, glycophorin A), and megakaryocytic (CD41, CD61) reagents should be included in the essential panel. However, there was no agreement as to which was optimal. Thus, approximately 13--15 of those reagents would be considered essential in all cases of AL, whereas others (CD16, CD56, CDw65, TdT, and cytoplasmic CD3) were mentioned as useful in some cases. Almost all voting participants believed that the appropriate number of markers for complete characterization of AL would average 20--24. The majority of the responders (11 of 13) indicated that fewer reagents could be used in monitoring or staging patients with previously characterized disease, but not all ventured a specific number of reagents. From the above results, we conclude that the phenotypic analysis of hematologic and lymphoid neoplasia requires a rather extensive panel of reagents. Supplementary reagents might even be necessary if they prove to become relevant for diagnostic purposes. Reducing the number of antibodies could significantly compromise the diagnostic accuracy, appropriate monitoring, or therapy of these disorders.
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PMID:Optimal number of reagents required to evaluate hematolymphoid neoplasias: results of an international consensus meeting. 1124 3

T-cell prolymphocytic leukemia (T-PLL) is a postthymic T-cell neoplasm with a characteristic morphology and heterogeneous immunophenotype. Most cases of T-PLL express membrane T-cell receptors (TCRs) of the alphabeta phenotype. We experienced a 30-year-old man suffering from TCRgammadelta T-cell leukemia with morphology compatible to T-PLL with a postthymic phenotype. He was admitted with skin eruption and pancytopenia. Peripheral blood and bone marrow were occupied with medium-sized lymphocytes, which had moderately condensed chromatin with a single nucleolus and sparse, nongranular basophilic cytoplasm. The immunophenotype was CD1a-, CD2-, CD3+, CD4-, CD5+, CD7+, CD8-, and terminal deoxynucleotidyl transferase negative. Hepatosplenomegaly was absent. He was diagnosed as having T-PLL and was treated with combination chemotherapy. Six months later the leukemic cell became chemoresistant. Although the patient showed transient improvement in response to pentostatin, he died 13 months after the diagnosis. To our knowledge, this is the first case of T-PLL with a TCRgammadelta phenotype.
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PMID:T-cell receptor gammadelta T-cell leukemia with the morphology of T-cell prolymphocytic leukemia and a postthymic immunophenotype. 1179 17

A subset of blood mononuclear cells from patients with chronic lymphocytic leukemia (CLL) can differentiate in vitro into "nurselike" cells (NLCs) that can protect CLL cells from apoptosis. NLCs express cytoplasmic vimentin and stromal-derived factor 1 (SDF-1). NLCs also express CD14, as well as CD11b, CD33, CD40, CD45RO, CD68, CD80, CD86, HLA-DQ, and HLA-DR, but not CD1a, CD2, CD3, CD11c, CD19, CD45RA, CD83, CD106, or CD154. Consistent with this phenotype, NLCs failed to differentiate from blood mononuclear cells that were depleted of CD14+ cells or from isolated CD19+ cells. CD14+ blood cells of healthy donors could differentiate into cells with the morphology and phenotype of NLCs when cultured in direct contact with CLL B cells, but not with normal B cells. Despite expressing antigens in common with blood monocytes, monocyte-derived dendritic cells, and macrophages, NLCs expressed significantly higher levels of CD68 than these other cell types. Consistent with the notion that NLCs are present in vivo, CD14+ splenocytes from CLL patients have NLC morphology and express significantly higher levels of CD68 than CD14+ splenocytes from persons without known B-cell malignancy. These findings indicate that although NLCs may differentiate from blood monocytes, they probably represent a distinctive hematopoietic cell type that exists in vivo, differentiates from hematopoietic CD14+ cells in the context of CLL, and in turn protect CLL cells from apoptosis via a mechanism that is independent of CD106 (vascular cell adhesion molecule-1). The interaction between CLL cells and NLCs may represent a novel target for therapy of patients with this disease.
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PMID:Distinctive features of "nurselike" cells that differentiate in the context of chronic lymphocytic leukemia. 1180 9

Gamma/delta T-cell lymphoma is a rare neoplasm that is not well characterized and is associated with a poor prognosis. We report a case of gamma/delta peripheral T-cell lymphoma that appeared as a breast lump in a 35-yr-old woman. The patient was examined for a 2-mo history of a right-sided breast mass with associated hepatosplenomegaly 2 yr in duration. A fine-needle aspiration biopsy (FNAB) was performed, and the diagnosis of lymphoma was rendered. The patient received two cycles of CHOP and is alive with persistent disease. FNAB showed evidence of polymorphous lymphoma, consisting of medium-size to large cells with immature chromatin. Flow cytometric immunophenotyping showed expression of CD2, CD3, and CD7 with lack of expression of CD1a, CD4, CD5, CD8, and CD56. Flow cytometry also showed predominant expression of the gamma/delta T-cell receptor. Cytogenetic analysis showed 48XX+i7(q11.2),+7(3). Our case indicates that gamma/delta peripheral T-cell lymphoma can be diagnosed by FNAB. This rare entity requires further investigation.
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PMID:gamma/delta peripheral T-cell lymphoma of the breast diagnosed by fine-needle aspiration biopsy. 1189 23

Hematopoietic neoplasm coexpressing CD4 and CD56 includes a subset of acute myeloid leukemia with myelomonocytic differentiation, plasmacytoid monocyte tumor, and other immature hematopoietic neoplasms of undefined origin. Herein, we report a CD4+CD56+CD68+ hematopoietic tumor that was thought to be a tumor of plasmacytoid monocytes. This case is unique in the absence of accompanying myelomonocytic leukemia and the faint expression of cCD3 on the tumor cells. The patient was a 22-yr old man presented with multiple lymphadenopathy and an involvement of the bone marrow. Tumor cells were large and monomorphic with an angulated eosinophilic cytoplasm of moderate amount. Nuclei of most tumor cells were eccentric and round with one or two prominent nucleoli. Rough endoplasmic reticulum was prominent in electron microscopic examination. Tumor cells expressed CD4, CD7, CD10, CD45RB, CD56, CD68, and HLA-DR and were negative for CD1a, CD2, sCD3, CD5, CD13, CD14, CD20, CD33, CD34, CD43, CD45RA, TIA-1, S-100, and TdT. cCD3 was not detected in the immunostaining using paraffin tissue, but was faintly expressed in flow cytometry and immunostaining using a touch imprint slide. T-cell receptor gene rearrangement analysis and EBV in situ hybridization showed negative results. Cytochemically, myeloperoxidase, Sudan black B, and alpha naphthyl butyrate esterase were all negative.
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PMID:CD4+CD56+CD68+hematopoietic tumor of probable plasmacytoid monocyte derivation with weak expression of cytoplasmic CD3. 1248 12

A 77-year-old woman presented to the outpatient hematology clinic in August 2001 with leukocytosis, recurrent bacterial infections, sweating and weight loss. Bone marrow biopsy showed 80% infiltration with lymphoid cells having a prolymphocytic morphology. Flow-cytometric immunophenotype analysis showed that over 80% of the cells were positive for CD2, CD3, CD4, CD5 and CD7 antigens and negative for terminal deoxynucleotidyl transferase and CD1a antigens. T cell prolymphocytic leukemia (T-PLL) was diagnosed on the basis of these findings. The diagnosis was later confirmed by cytogenetic analysis and fluorescence in situ hibridization. The patient had the following karyotype: 46,X,der(X)t(X;3) (q28;p25) t(X;16)(p14;q12), der(3) t(X;3)(q28;p25), der(6) t (X;6) (p14;q25), (8) (q10), del(11) (q14q23), der(13) t (5;13) (q34;p11), der(13) t(13;14)(q22;q11), inv(14)(q11q32), der (16) t(X;16)(q28;q12), r(17)(p13q21), der(20) t(17;20) (q21; q13),22p+. The cytogenetic rearrangements der(6)t(X;6) (p14;q25), der(13)t(13;14)(q22;q11),t(5;13)(q34;p11), r(17) (p13q21) and t(17;20)(q21;q13) have not been described previously in the literature in patients with T-PLL.
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PMID:T cell prolymphocytic leukemia with new chromosome rearrangements. 1503 40

T-cell prolymphocytic leukemia (T-PLL) is a rare postthymic T-cell disorder. The disease is characterized by lymphadenopathy, splenomegaly, skin lesions, a high white blood cell count, and an aggressive clinical course. The small cell variant of T-PLL occurs in approximately 20% of patients. Most T-PLL patients express membrane T-cell receptors (TCR) of the alphabeta phenotype. The diagnosis of small cell variant T-PLL in a 56-year-old woman was based on the findings of abnormal lymphocytosis, immunophenotype, lymphadenopathy, and aggressive clinical behavior. Immunophenotype analysis showed that lymphocytes were positive for CD2, CD3, CD5, CD7, CD8, and TCR gammadelta antigens and negative for CD1a, CD4, and TCR alphabeta antigens. Southern blot analysis revealed rearrangement of the TCR Jgamma and Jdelta-1 genes. A cytogenetic study of peripheral blood showed a normal karyotype. T-PLL with a TCR gammadelta phenotype is very rare. This case was typical T-PLL except for the morphologically small cell type and the lack of the typical chromosome aberration. If cases accumulate in the future, the specific features of the gamma8 type of T-PLL will become clearer.
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PMID:Small cell variant of T-cell prolymphocytic leukemia with a gammadelta immunophenotype. 1571 92


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