Familial hemophagocytic lymphohistiocytosis (FHL) is a rapidly fatal illness, usually encountered in infancy, characterized by fever, hepatosplenomegaly, pancytopenia, and central nervous system involvement. Microscopic examination of tissue shows a non-malignant lymphohistiocytic infiltrate, with prominent erythrophagocytosis. FHL is an autosomal recessive hereditary disorder but may develop secondarily to other conditions such as immunosuppression, malignancies, fat overload and certain infections. We recently experienced a case of siblings developing FHL, which may be associated with EBV infection.
Case Report ; Child, Preschool ; Female ; Herpesviridae Infections/complications* ; Herpesvirus 4, Human* ; Histiocytosis, Non-Langerhans-Cell/virology* ; Histiocytosis, Non-Langerhans-Cell/genetics* ; Human ; Infant ; Male ; Tumor Virus Infections/complications*

Immunohistochemical study on 26 cases of Langerhans cell histiocytosis (LCH) using several leukocyte antibodies in addition to traditionally used markers (S-100 protein and peanut agglutinin) revealed that the proliferating cells of LCH expressed UCHL1, MT1 as well as classically known positivity for S-100 protein, HLA-DR and peanut agglutinin but were negative for OPD4. In comparison to S-100 protein peanut agglutinin (PNA) using a two stage method produced weaker staining and positively stained cells were sparse. Also in this study, a small proportion of proliferating cells in LCH was observed to be reactive for both myeloid/macrophage antigens (KPI, MAC 387 and lysozyme) and Langerhans cell marker (S-100 protein), verifying the existence of a hybrid form of histiocytes.
Adolescent ; Adult ; Antigens/*genetics ; Child ; Child, Preschool ; Female ; Histiocytosis, Langerhans-Cell/*immunology/pathology ; Human ; Immunohistochemistry/methods ; Infant ; Male ; Middle Age ; Phenotype ; Staining and Labeling ; Support, Non-U.S. Gov't