title: The Omenn's syndrome: histological, immunohistochemical and ultrastructural evidence for a partial T cell deficiency evolving in an abnormal proliferation of T lymphocytes and S-100 +/T-6 + Langerhans-like cells.
abstract: A 7 month old female infant was affected by a rapidly fatal familial disease highly reminiscent of Omenn's syndrome. She presented with widespread eczematous lesions, hepatosplenomegaly, superficial lymphadenopathy, peripheral blood lymphocytosis, eosinophilia and hyper-IgE. An axillary lymph node was involved by a marked proliferation of T-3 +/T-10-- lymphocytes admixed with S-100+/T-6+/Leu-3a+/Ia + reticular cells which lacked typical LC granules; cell suspension study revealed that 90%-96% of the lymph node cells were T-11+/T-3+ lymphocytes characterized by low expression of Leu-3a and T-8 antigens and by high expression of Ia antigens (52%). Peripheral blood T lymphocytes exhibited a similar distribution of surface phenotypes. The patient died of interstitial pneumonia and an autopsy was performed. The thymus was markedly atrophic and completely devoid of lymphocytes. The peri-arteriolar lymphoid sheets of the spleen were poorly developed and were mainly composed of T-8+ lymphocytes. The mediastinal nodes were rudimentary and were populated by T-3+/T-10+ lymphocytes with low expression of Leu-3a and T-8 antigens. Our results raise the possibility that Omenn's syndrome is a peculiar primary immunodeficiency in which, despite early thymic involution, some abnormal T lymphocytes still develop in the peripheral lymphoid organs. Antigenic triggering of these cells might result in prominent proliferations of T lymphocytes and Langerhans-like cells which lead to the clinical manifestation of the disease.
mesh_terms: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000032:analysis; D001344:Autopsy; D001706:Biopsy; D002455:Cell Division; D005260:Female; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000473:pathology*; D007223:Infant; D007801:Langerhans Cells / Q000166:cytology* / Q000276:immunology / Q000648:ultrastructure; D008198:Lymph Nodes / Q000473:pathology*; D008854:Microscopy, Electron; D009418:S100 Proteins / Q000032:analysis; D013154:Spleen / Q000473:pathology; D013577:Syndrome; D013601:T-Lymphocytes / Q000166:cytology* / Q000648:ultrastructure; D013950:Thymus Gland / Q000473:pathology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D009418:S100 Proteins