Sinus histiocytosis with massive lymphadenopathy: virological, immunological and morphological studies.

The histiocytes from a patient with sinus histiocytosis were tested for the presence of Epstein-Barr viral nuclear antigen (EBNA) before and after in vitro growth. On both occasions the histiocytes as well as the lymphocytes were EBNA negative. Likewise the profile of EBV viral capsid antibody (VCA) suggests that this virus is unlikely to be directly involved in the development of the disease. The maintenance of an unusually high level of antibodies to EBV and measles, both viruses which produce persistent infections, indicates that the humoral immune response is active. That a normal humoral response occurred in response to mumps virus during the same period suggests that a deficiency in the cell mediated immune response to the persistent viruses might be the reason for the abnormally high antibody levels. The fresh as well as the cultured histiocytes had only Fc receptors. The affected lymph node lymphocytes developed unusual large inclusion bodies following in vitro culture.