Eosinophilia-myalgia syndrome: a clinicopathological study of four patients

Eosinophilia-myalgia syndrome is an idiopathic disorder characterized by myalgia, especially of the extremities and peripheral eosinophilia. It is found in some patients as a result of tryptophan ingestion. We examined four patients showing clinical features and muscle biopsy changes consistent with eosinophilia-myalgia syndrome. The results of conventional histology were compared with immunohistochemical studies using monoclonal antibodies to human T lymphocytes, macrophages, HLA-DR antigen. Our findings confirm the potential importance of lymphocytes and macrophages in this syndrome. In particular, new observations are presented concerning the immunoreactivity of HLA-DR antigen.