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)

Antigen-driven interaction of dendritic cells (DC) with CD4(+) T(h) cells results in the exchange of bidirectional activating signals. Cross-linking of TCR by MHC class II-bound antigen activates T(h) cells, resulting in their up-regulation of CD40 ligand. Here we show that MHC class II molecules, in addition to their passive role in DC-T(h) cell interaction, can also actively induce DC maturation. Cross-linking of MHC class II molecules on human monocyte-derived DC results in the up-regulation of the surface expression of CD83, CD80, CD86, CD54, CD1a and CD40 molecules, the typical DC maturation-associated markers. It also promotes a rapid homotypic aggregation of DC paralleled by the up-regulation of such adhesion molecules as VLA-4, tissue transglutaminase, CD54 and CD11c. The impact of MHC class II cross-linking upon DC was context dependent. The outcome of MHC class II signaling depends on the maturation status of DC. While the cross-linking of MHC class II on immature DC promoted their maturation, the dominant effect upon the DC that were previously matured was the induction of DC apoptosis. Our current observations indicate that, in addition to the previously reported negative impact of MHC class II-mediated signaling on DC function, it also promotes DC maturation, participating in the enhancement of DC stimulatory function. Importantly, MHC class II-induced DC maturation and apoptosis are mediated by different signaling pathways, sensitive to different sets of inhibitors. This opens the possibility of differential regulation of each of these events in immunotherapy.
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PMID:Differential regulation of maturation and apoptosis of human monocyte-derived dendritic cells mediated by MHC class II. 1220

Indeterminate cell histiocytosis is a rare neoplasm composed of cells with mixed characteristics of Langerhans cells and non-Langerhans cells. An otherwise healthy, 36-year-old woman presented with asymptomatic generalized papules and nodules that had appeared on all four extremities, the trunk, and cheeks in the previous 6 months. The lesions were firm, painless, non-pruritic, and slightly flesh-yellow or reddish-brown in color. Histopathologic, immunohistochemical examination and electron microscopic studies showed characteristic findings of indeterminate cell histiocytosis: diffuse proliferative histiocytes infiltrating the dermis without epidermotropism or atypia; neoplastic cells expressing markers characteristic of both Langerhans cells (CD1a, S-100) and focal monocytes/macrophages (Factor XIIIa, CD68); and no Birbeck granules within the cytoplasm of the neoplastic cells. Flow cytometry revealed more CD34+ cells in the peripheral blood of the patient than in peripheral blood from a control. Interestingly, the patient responded favorably to psoralen ultraviolet A-range treatment. Herein, we present this case and review the literature.
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PMID:Indeterminate cell histiocytosis: a case report. 1548 63

The distribution of specific histiocyte subsets within the human gastrointestinal tract has not been extensively characterized. Our goal was to immunohistochemically evaluate the distribution and location of CD1a-positive, CD68-positive, and Factor XIIIa (FXIIIa)-positive histiocyte subsets within the normal gastrointestinal tract and attempt to relate distribution to possible function. Twenty-nine samples of normal esophagus, stomach, small bowel, large bowel, and anus were routinely processed and immunohistochemically stained with antibodies to CD68, CD1a, and FXIIIa. The distribution and histologic location of histiocyte subsets were qualitatively analyzed. CD1a-positive cells were seen exclusively within anal and esophageal squamous mucosa. CD68 positive histiocytes were present in lamina propria and submucosa throughout the gastrointestinal tract and in Peyer patches. FXIIIa-positive histiocytes were also abundant in lamina propria and submucosa throughout the gastrointestinal tract, particularly around pericryptal sheaths and in parafollicular regions surrounding Peyer patches. Our results showed that there are distinct subpopulations of gastrointestinal histiocytes, and that distribution varies according to both cell type and site. Because Langerhans cells are epidermal antigen processing/presentation cells, their exclusive presence in squamous mucosa suggests an analogous function there. The prominence of both CD68 and FXIIIa-positive cells surrounding glandular pericryptal sheaths suggests that they are important to immune function at this mucosal interface and may play a role in communication between glands and lamina propria. In addition, the presence of specific histiocyte subsets within Peyer patches and para-follicular regions suggests that they are involved in different aspects of antigen processing associated with gut lymphoid tissue. Further studies are needed to explore the relation between specific histiocyte subsets and gastrointestinal disease processes.
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PMID:Histiocytic subpopulations in the gastrointestinal tract: distribution and possible relationship to function. 1553 37

Systemic form of juvenile xanthogranuloma with involvement of liver and bone marrow is reported in a 2-month-old female infant who presented with hepatosplenomegaly, severe anemia, and thrombocytopenia. There was no skin lesion, nor bone lesion. The enlarged liver has generalized yellowish spots. The diagnosis of juvenile xanthogranuloma was made by pathologic findings of marrow and portal tract infiltration by S-100 negative, CD1a negative, CD68 positive, and Factor XIIIa positive large pale to foamy histiocytes with Touton giant cells, and lack of Langerhans cell granule by electron microscopic examination. The patient was treated with Vinblastine and Etoposide, and experienced slow and gradual disease regression in one year. To the best of knowledge, this is the first documented case of bone marrow involvement in systemic juvenile xanthogranuloma.
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PMID:Systemic form of juvenile xanthogranuloma: report of a case with liver and bone marrow involvement. 1563 May 37

The molecular mechanisms involved in the pathogenesis of toxic epidermal necrolysis (TEN) remain not fully understood. We report a unique case of antibiotic-induced TEN developed in a patient who also suffered from prolonged severe methotrexate-induced pancytopenia. The objective of the study was to explore the nature of the cutaneous inflammatory infiltrate and the density in dermal dendrocytes (DD). Immunohistochemistry was used to identify activated T lymphocytes (CD45R0), monocyte-macrophages (Mac 387, CD68), DD (Factor XIIIa), and Langerhans cells (CD1a). The proliferation marker (Ki67) and the antibody to Fas receptor (CD95R) were also used to assess the distribution of the germinative pool of keratinocytes and the FAS-related apoptotic process, respectively. Numerous Factor XIIIa+ DD were present in the papillary dermis with only sparce perivascular CD45RO+ T lymphocytes and scattered CD68+ or Mac 387+ macrophages. Double immunostainings revealed that a minority of Factor XIIIa+ DD co-expressed the CD68 glycoprotein (a marker of phagocytic activity). No cells co-expressed factor XIIIa and Mac 387 immunoreactivities. CD45RO+ T lymphocytes, CD68+ and Mac 387+ macrophages were absent in the epidermis. The expression of CD95R was present although restricted to the basal keratinocytes, while the L1-protein (Mac 387+) was diffusely present in the epidermis. Langerhans cells (CD1a+) were sparce, but normal in distribution. The presence of a great number of Factor XIIIa+ DD without any possible recent recruitment from bone marrow suggests that these cells differentiated from resident cells of the skin. Indeed, there was no co-expression of Factor XIIIa and L1-protein, thus showing the absence of recruitment from monocytes. The simultaneous over-expression of Factor XIIIa and CD68 in some DD indicates some phagocytic activity. In view of the absence of inflammatory cells in the epidermis, keratinocytes appeared responsible for their own destruction through CD95-mediated and/or calcium-dependent apoptotic pathways. This finding entails that TEN treatments should target the keratinocyte metabolism rather than the circulating inflammatory cells which presumably play a limited role, if any, in the epidermal destructive process.
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PMID:Drug-induced toxic epidermal necrolysis and pancytopenia: a puzzling association. 1594 74

Progressive mucinous histiocytosis is a rare, benign, non-Langerhans' cell histiocytosis limited to the skin. Ten cases--all women--in four families and one sporadic case have been described in the literature. The disorder usually begins in childhood and progresses slowly. We report two sporadic cases of adult-onset progressive mucinous histiocytosis in unrelated African-American women, aged 48 and 55 years, respectively, who developed red-brown and flesh-coloured, asymptomatic papules on the face, the arms and the legs without truncal, mucosal or visceral involvement. The lesions showed no spontaneous regression. Both patients lacked associated systemic symptoms, including polyuria, polydipsia or seizures. There was no underlying hyperlipidaemia, paraproteinaemia or lymphoproliferative disease. No family history of similar lesions could be identified. Light microscopy revealed dermal proliferation of spindle-shaped histiocytes with abundant mucin deposition. Electron microscopy demonstrated a high number of myelin figures or zebra bodies in the cytoplasm of histiocytes. On immunohistochemistry, positive staining with macrophage markers--CD68, HAM56 and lysozyme--and factor XIIIa, a transglutaminase present in dermal dendrocytes, and negative staining with Langerhans' cell markers--CD1a and S100--and CD34, a marker present in dermal dendritic cells derived from uncommitted mesenchymal cells, were observed.
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PMID:Two sporadic cases of adult-onset progressive mucinous histiocytosis. 1642 Mar 13

Indeterminate cell histiocytosis (ICH) is a rare disorder in which histiocytic cells proliferate, expressing markers of both X- and non-X histiocytosis. Nevertheless, it is not totally clear if both types of markers are co-expressed by the same cell in this disorder, or on the contrary, the histiocytosis is made of two phenotypically different types of cells. Some recent reports seem to indicate this latter option, since there is a non-homogeneous distribution of the cells in the dermis. The ones in the most superficial part of the biopsy would lose some of their markers when moving towards the bottom part of the dermis. In order to check if there is co-expression of CD1a and CD68 by the same cell, we performed an immunohistochemical study with double staining, in a case of ICH of a 74-year-old male, who presented multiple yellowish papules in chest, back and both arms. Their sizes varied between 1 and 3 mm. One of the biopsies from one lesion of the back showed a dermal histiocytic infiltrate, which expressed S-100, CD1a, Factor XIIIa and CD68 in the common immunohistochemical study. Birbeck granules were not found in the ultrastructural study. Our results with the double stain for CD1a and CD68 demonstrated that most of the histiocytes expressed either one marker or the other. Nevertheless, some of the histiocytes of the infiltrate co-expressed both markers. In all the cases, the cells with this combined phenotype were mononuclear. Although CD1a was mainly expressed by the cells at the top of the dermis, some cells of the deep dermis kept expressing this marker. The cells expressing both markers were mostly found in the top part of the dermis. The multinucleate cells expressed only CD68, but not CD1a.
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PMID:Double immunostaining with CD1A and CD68 in the phenotypic characterization of indeterminate cell histiocytosis. 1881 25

Indeterminate cell histiocytosis (ICH) is a rare, heterogeneous disorder that is characterized by immunophenotypic features of both Langerhans cell histiocytosis (LCH) and non-LCH. We describe a 12-month-old boy with a four-month history of asymptomatic, small, pink-tan papules on his face. Histopathologic evaluation showed a superficial, dermal infiltrate of histiocytes that was positive for S100, CD1a, CD68, and Factor XIIIa. To our knowledge, this represents the first report of the clinical presentation of benign cephalic histiocytosis with immunohistochemical findings of ICH. We review the classification of histiocytic disorders and the clinical and immunohistochemical features of both ICH and benign cephalic histiocytosis.
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PMID:Indeterminate cell histiocytosis that presented clinically as benign cephalic histiocytosis. 2552 30

Dermatofibromas are most frequently encountered in women on the lower extremities, often after minor trauma. A recurrent lesion of the right lower eyelid developed in a 64-year-old woman. It harbored "monster cells" that were large, with either multiple nuclei or a single, large, convoluted, and hyperchromatic nucleus. The presence of these cells does not signify a malignant transformation. The background cells were either histiocytoid (many were adipophilin positive), spindled cells, or dendritiform cells without mitoses. Factor XIIIa, CD68, and CD163 immunostaining was positive, and a subpopulation of CD1a+ Langerhans cells was intermixed. Facial and eyelid dermatofibromas are more likely to recur and deserve wider, tumor-free surgical margins. Their microscopic differential diagnosis includes a cellular scar, peripheral nerve tumor, atypical fibrous xanthoma, and dermatofibrosarcoma protuberans.
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PMID:Dermatofibroma of the eyelid with monster cells. 2801 79

Infantile systemic juvenile xanthogranuloma (ISJXG) is an uncommon form of juvenile xanthogranuloma, a non-Langerhans cell proliferation of infancy and early childhood. In a small percentage of patients, the visceral involvement-most commonly to the central nervous system, liver, spleen, or lungs-may be associated with severe morbidity, and eventually fatal outcome. Here we describe the clinical and pathological findings of a 28-day-old girl with ISJXG who died with respiratory distress syndrome. She had few cutaneous lesions but massive liver and spleen infiltration; other affected organs were multiple lymph nodes, thoracic parasympathetic nodule, pleura, pancreas, and kidneys. Additional findings were mild pulmonary hypoplasia and bacteremia. Immunohistochemistry on fixed tissues is the standard for diagnosis. Immunophenotype cells express CD14, CD68, CD163, Factor XIIIa, Stabilin-1, and fascin; S100 was positive in less than 20% of the cases; CD1a and langerin were negative. No consistent cytogenetic or molecular genetic defect has been identified. This case demonstrates that the autopsy is a handy tool, because hepatic infiltration, which was not considered clinically, determined a restrictive respiratory impairment. In our opinion, this was the direct cause of death.
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PMID:Infantile systemic juvenile xanthogranuloma case with massive liver infiltration. 3108 76


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