Disseminated echovirus infection in a patient with multiple myeloma and a functional defect in complement. Treatment with intravenous immunoglobulin

A man with IgG1 multiple myeloma developed fever, confusion, and progressive muscle weakness resulting in paralysis. Echovirus type 11 was isolated from cerebrospinal fluid, pleura, pleural fluid, and muscle, and muscle biopsy disclosed changes consistent with viral myositis. Immunologic evaluation revealed low serum levels of polyclonal IgG subtypes 1 and 3, reduced blood levels of T-helper/inducer and T-suppressor/cytotoxic cells, and a complement abnormality involving the function of the classical pathway C3 convertase, C4b2a. Therapy with intravenous immunoglobulin was associated with clinical recovery. This is the first reported case of disseminated central nervous system enteroviral infection in an adult with a B-cell malignancy, and in association with a documented complement abnormality. The findings suggest the efficacy of immunotherapy in this disease.