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)

The lone CX3C chemokine, fractalkine (FK), is expressed in a membrane-bound form on activated endothelial cells and mediates attachment and firm adhesion of T cells, monocytes and NK cells. We now show that FK is associated with dendritic cells (DC) in epidermis and lymphoid organs. In normal human skin, dual-color fluorescence microscopy co-localized FK expression with Langerhans cells expressing CD1a. In tonsil, FK-positive DC expressed CD83, a marker for mature DC. Human and murine cultured DC up-regulated FK mRNA expression with maturation. Furthermore, CD40 ligation, but not TNF-alpha or lipopolysaccharide treatment, of activated, migratory DC that had migrated from skin explants resulted in a 2.5-fold increase of surface expression of FK without significant alterations of expression of CD80, CD86, CD54 or MHC class II. Since FK mediates adhesion of T cells to activated endothelial cells, the increased expression of FK during DC maturation (and particularly by CD40 ligation) may play a role in the ability of T cells and mature DC to form conjugates and engage in cell-cell communication.
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PMID:Fractalkine, a CX3C chemokine, is expressed by dendritic cells and is up-regulated upon dendritic cell maturation. 1045 70

Human peripheral blood contains two populations of dendritic cells (DC) but their developmental relationship has not been established. Freshly isolated CD11c- DC possessed a lymphoid morphology, lacked myeloid markers but expressed lymphoid markers (CD4+ CD10+) whilst the CD11c+ DC were monocytoid in appearance and expressed myeloid markers. Although both populations were allostimulatory, only the CD11c+ DC were able to take up antigen. Irrespective of the culture conditions the CD11c- cells developed into CD11c- CD13- CD33- CD4+ CD1a- CD83+/- DC. In contrast, cultured CD11c+ cells developed the phenotype CD11c+ CD13+ CD33+/- CD4- CD1a+ CD83+ CD9+. Only the CD11c+ DC expressed macrophage colony-stimulating factor (M-CSF) receptor and gave rise to CD14+, esterase+, phagocytic macrophages when cultured in M-CSF. These data suggest that these two populations of DC represent distinct lineages of antigen-presenting DC.
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PMID:Human peripheral blood contains two distinct lineages of dendritic cells. 1050 51

We have characterized dendritic cell precursors (pre-DC) in the human thymus. These CD1a(-)CD3(-)CD4(+)CD8(-) cells express high levels of interleukin-3Ralpha (IL-3Ralpha) on the membrane and are able to develop into mature DC upon culture with IL-3 and CD40 ligation. The DC precursors are predominantly located in the thymic medulla. Interestingly, the pre-DC express pTalpha mRNA, which is also present in CD1a(+)CD3(-)CD4(+)CD8(-) pre-T cells. Yet, the pre-DC lack expression of recombination activating gene-1 mRNA and fail to develop into T cells in appropriate assays. The thymic pre-DC are very similar to the recently characterized pre-DC found in the T cell areas of the tonsil, and it is suggested that these pre-DC populations are of lymphoid origin.
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PMID:Expression of pTalpha mRNA in a committed dendritic cell precursor in the human thymus. 1051 68

Interleukin-15 (IL-15) is a pleiotropic cytokine that induces the generation and differentiation of lymphoid cells and shares many biological activities with IL-2. We have shown here the development of dendritic cells (DC) from human CD34+ hemopoietic precursor cells cultured for 2-4 weeks with IL-15 alone. DC generated with IL-15 have typical morphological, immunocytochemical, phenotypic, and functional characteristics of mature DC. Dual flow cytometry analysis performed weekly demonstrated increasing co-expression of CD1a or CD83 with HLA-DR, CD80, CD86, IL-2R alpha, beta, and gamma. Two populations of cells were distinguished among CD34+ progeny. Small and medium-size cells were mainly natural killer (NK) cells (72.6-85.2% CD56+) and low numbers of DC (9.1-21.3% CD1a+). Large cells were mostly DC (75.4-95.4% CD1a+). Isolated CD34+ cells did not express IL-2R subunits but after 2-3 days in culture with IL-15, they were found to express IL-2Rgamma. Induced expression of IL-2Rgamma on CD34+ cells may explain the primary mechanism of IL-15-regulated differentiation of hemopoietic precursor cells. Thus, our data suggest that IL-15 stimulates CD34+ cells to differentiate into NK and DC and may represent a new growth and survival factor for lymphoid DC.
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PMID:The generation of human dendritic and NK cells from hemopoietic progenitors induced by interleukin-15. 1053 23

Lymphoblastic leukemia/lymphoma (LBL) is a malignant neoplasm of precursor lymphocytes of B- or T-cell phenotype. Involvement of the skin is relatively uncommon. We examined retrospectively the clinicopathologic, immunophenotypic, and molecular genetic features of six patients with cutaneous involvement of LBL (B-LBL=5; T-LBL=1). Patients presented clinically with solitary, large tumors located on the head (3 cases) or the back (1 case), or with generalized tumors (2 cases). Ulceration was uncommon. In two patients the onset of skin lesions was concomitant to the diagnosis of lymphoblastic leukemia. Histopathologic examination showed in all cases a dense, diffuse, monomorphous infiltrate located in the entire dennis and subcutaneous fat. A typical "starry sky" pattern was observed in the majority of the lesions. In some areas neoplastic cells were aligned in a "mosaic-like" fashion. Cytomorphologically, medium sized lymphoid cells with round or convoluted nuclei, inconspicuous nucleoli and scant cytoplasm predominated. There were no significant differences in the histopathologic features of skin lesions in T- and B-LBL. In B-LBL, CD79a was more useful than CD20 in determining the phenotype of neoplastic cells (4/5 cases positive for CD79a as compared to 2/5 cases positive for CD20). TdT, CD10 and CD43 were positive in 4 cases, CD34 in 2. The case of T-LBL revealed positivity for CD1a, CD3, CD43 and TdT, and negativity for CD34 and for B-cell markers. All neoplasms were positive for CD99 and bcl-2, and showed a high proliferation rate. Molecular genetic analysis of J(H) and T-cell receptor (TCR) genes performed using a polymerase chain reaction technique revealed a monoclonal rearrangement of J(H) genes in all five B-LBLs. One of these cases showed also a concomitant TCR-gamma gene rearrangement. A monoclonal rearrangement of the TCR-gamma gene was detected in the case of T-LBL. Our study shows that skin lesions of LBL present characteristic clinicopathologic and molecular features allowing the differentiation from other cutaneous lymphomas, even in cases without clinical history of previous precursor lymphoblastic leukemia/lymphoma.
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PMID:Cutaneous involvement in lymphoblastic lymphoma. 1055 9

We report the clinical, histopathologic, and immunohistologic features of 15 cases of pseudolymphomatous folliculitis (PLF). The patients comprised seven males and eight females (mean age, 38.6 years; age range, 2-67 years). All patients had dome-shaped or flat-elevated nodules suggestive of cutaneous lymphoid hyperplasias (CLHs). The lesions were solitary in all 15 cases, except in one case with duplex lesions. All lesions were located on the face and measured less than 1.5 cm. In 14 cases with one lesion each, five lesions showed rapid regression after incisional biopsy, whereas the remaining nine underwent excisional biopsy. In the case with duplex lesions, one regressed spontaneously after excisional biopsy of the other. Histopathologically, all PLFs showed dense lymphocytic infiltrates from the dermis to the subcutis simulating cutaneous lymphomas. The walls of hair follicles in all cases were enlarged and irregularly deformed with their epithelium blurred by lymphocytic infiltrates; we called this change "activation" of hair follicles. In nine cases, many atypical lymphocytes were intermingled; three of these cases had been misdiagnosed as cutaneous T-cell lymphoma at other institutions. Immunohistologically, 10 and 5 cases showed predominantly B cells and predominantly T cells, respectively. Remarkably, all lesions showed increased numbers of perifollicular histiocytes expressing anti-S-100 protein and CD1a, and seven lesions showed histiocytes in aggregates. We conclude that PLF is a subset of CLH with characteristic clinical and pathologic features showing perifollicular clustering of T-cell-associated dendritic cells with activation of pilosebaceous units. PLF is an entity to be differentiated from malignant lymphomas and other cutaneous pseudolymphomas.
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PMID:Pseudolymphomatous folliculitis: a clinicopathologic study of 15 cases of cutaneous pseudolymphoma with follicular invasion. 1055 99

Infection with Helicobacter pylori (Hp) induces the formation of lymphoid tissue in the stomach and the occasional development of primary gastric B-cell lymphomas. We have studied the expression of 2 chemokines that attract B lymphocytes, BCA-1 and SLC, in gastric tissue samples obtained from patients with chronic gastritis induced by Hp infection or nonsteroidal anti-inflammatory drugs, as well as from patients with Hp-associated low-grade and high-grade gastric lymphomas. High-level expression of BCA-1 and its receptor, CXCR5, was observed in all mucosal lymphoid aggregates and in the mantle zone of all secondary lymphoid follicles in Hp-induced gastric mucosa-associated lymphoid tissue (MALT). Follicular dendritic cells and B lymphocytes are possible sources of BCA-1, which is not expressed by T lymphocytes, macrophages, or CD1a(+) dendritic cells. Strong expression of BCA-1 and CXCR5 was also detected in the transformed B cells of gastric MALT lymphomas. By contrast, SLC was confined almost exclusively to endothelial cells in and outside the lymphoid tissue. Only scant, occasional SLC expression was observed in the marginal zone of MALT follicles. Our findings indicate that BCA-1, which functions as a homing chemokine in normal lymphoid tissue, is induced in chronic Hp gastritis and is involved in the formation of lymphoid follicles and gastric lymphomas of the MALT type.
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PMID:BCA-1 is highly expressed in Helicobacter pylori-induced mucosa-associated lymphoid tissue and gastric lymphoma. 1056 92

We have analyzed the presence of immature and mature dendritic cells (DCs) within adenocarcinoma of the breast using immunohistochemistry. Immature DCs were defined by expression of CD1a-, Langerin-, and intracellular major histocompatibility complex class II-rich vesicles. Mature DCs were defined by expression of CD83 and DC-Lamp. Breast carcinoma cells were defined by morphology and/or cytokeratin expression. We demonstrate two levels of heterogeneity of DCs infiltrating breast carcinoma tissue: (a) immature CD1a(+) DCs, mostly of the Langerhans cell type (Langerin(+)), were retained within the tumor bed in 32/32 samples and (b) mature DCs, CD83(+)DC-Lamp(+), present in 20/32 samples, are confined to peritumoral areas. The high numbers of immature DCs found in the tumor may be best explained by high levels of macrophage inflammatory protein 3alpha expression by virtually all tumor cells. Confirming the immature/mature DC compartmentalization pattern, in vitro-generated immature DCs adhere to the tumor cells, whereas mature DCs adhere selectively to peritumoral areas. In some cases, T cells are clustering around the mature DCs in peritumoral areas, thus resembling the DC-T cell clusters of secondary lymphoid organs, which are characteristic of ongoing immune reactions.
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PMID:In breast carcinoma tissue, immature dendritic cells reside within the tumor, whereas mature dendritic cells are located in peritumoral areas. 1056 17

Lymphoid hyperplasia of Waldeyer's ring (WR) is an often-symptomatic complication of human immunodeficiency virus (HIV) infection. A characteristic but not well explained finding is the presence of multinucleated giant cells (MNGCs) adjacent to crypt or surface epithelium. To further elucidate the MNGCs and assess their relationship to HIV and Epstein-Barr virus (EBV), 12 specimens from 11 HIV-positive patients were stained with antibodies to HIV-1 p24, EBV (latent membrane protein, LMP-1), histiocytes (CD68), and other antigen-presenting cells: S-100 protein, the Langerhans cell (LC) marker CD1a, and the follicular dendritic cell (FDC) marker (CD21). Double immunofluorescent staining to assess co-expression of p24 and cell-specific markers was performed and analyzed by laser-scanning confocal microscopy with 3-dimensional reconstruction. In situ hybridization for EBV-encoded small RNA (EBER) was performed in all cases. Immunostains showed MNGCs labeled for p24, S-100, and CD68, but not CD1a. In 1 case, rare MNGCs were CD21-positive. EBV LMP-1 was uniformly negative, although EBER-positive lymphocytes were seen by in situ hybridization in 9 of 12 specimens (numerous in only 3 specimens). Double immunofluorescent staining showed co-localization of p24 with CD68 and S-100. Our results suggest that MNGCs are generally HIV-infected, EBV-negative, and most likely represent an unusual S-100-positive histiocyte subset (not LC or FDC). Their exact pathophysiologic role remains uncertain. EBV does not appear to play a major role in the pathogenesis of WR lymphoid hyperplasias in HIV infection.
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PMID:HIV-associated Waldeyer's ring lymphoid hyperplasias: characterization of multinucleated giant cells and the role of Epstein-Barr virus. 1057 22

Allergic sensitisation of the airways occurs in the mucosa of the shock organ, or in the lymphatic stations draining these structures. The lymphatic structure closest to the nasal mucosa in humans is the adenoid and in mice the nasal mucosa associated lymphoid tissue (NALT). In this study we tried to find evidence for our hypothesis that allergic sensitisation can occur in the adenoid (NALT). The first part of the investigation was set up to determine possible cellular changes in the adenoid of allergic children compared to non-allergic controls using immunohistochemical staining techniques. We found CD1a (Langerhans cells) and eosinophils to be more numerous in the adenoid of allergic children. In the second part of this study we used a murine model to determine if an intranasally applied 'allergen' is processed in the NALT and/or cervical lymph nodes (CLN). An auto fluorescent dye (Di I) was applied into the nasal cavity of mice. At subsequent time intervals mice were terminated. NALT and CLN tissue sections were placed under fluorescent microscopy. We found that Di I transported to both the NALT and CLN. However, the dye remained in the NALT at least 2 days longer than in the CLN. In these studies we found evidence that the lymphoid compartment in the upper respiratory tract (adenoid and NALT) are involved in the processes of allergic diseases.
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PMID:The role of the adenoid in allergic sensitisation. 1057 94


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