Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report on a patient with malignant histiocytosis (MH) presenting as multiple erythematous plaques and cutaneous depigmentation on her neck and chest. In a biopsy of an erythematous plaque, atypical large, foamy histiocytes infiltrated the dermis and positively stained with antibodies to lysozyme, leukocyte common antigen, and KP-1 (CD68). A few similar atypical cells were present in the superficial dermis focally in the depigmented areas. With use of immunohistochemical studies, most cases previously diagnosed as MH have been reclassified as T-cell lymphoma, B-cell lymphoma, or Ki-1-positive anaplastic large cell lymphoma. However, a few cases of "true" MH characterized by authentic histiocytes have been reported, presenting usually as red nodules. To our knowledge, our patient is the first with MH to present with erythematous plaques and vitiligo-like depigmentation.
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PMID:Malignant histiocytosis presenting as multiple erythematous plaques and cutaneous depigmentation. 918 20

Better understanding of tolerance and autoimmunity toward melanocyte-specific Ags is needed to develop effective treatment for vitiligo and malignant melanoma; yet, a systematic assessment of these mechanisms has been hampered by the difficulty in tracking autoreactive T cells. To address this issue, we have generated transgenic mice that express hen egg lysozyme as a melanocyte-specific neoantigen. By crossing these animals to a hen egg lysozyme-specific CD4 TCR transgenic line we have been able to track autoreactive CD4+ T cells from their development in the thymus to their involvement in spontaneous autoimmune disease with striking similarity to human vitiligo vulgaris and Vogt-Koyanagi-Harada syndrome. Our findings show that CD4-dependent destruction of melanocytes is partially inhibited by blocking Fas-Fas ligand interactions and also highlights the importance of local control of autoimmunity, as vitiligo remains patchy and never proceeds to confluence even when Ag and autoreactive CD4+ T cells are abundant. Immune therapy to enhance or suppress melanocyte-specific T cells can be directed at a series of semiredundant pathways involving tolerance and cell death.
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PMID:CD4 T cell-dependent autoimmunity against a melanocyte neoantigen induces spontaneous vitiligo and depends upon Fas-Fas ligand interactions. 1692 Sep 42