Hypogammaglobulinemia and Nocardia brain abscesses.

The host defense responses to Nocardia asteroides are not known. We have investigated a patient with common variable adult onset hypogammaglobulinemia who developed fatal disseminated nocardiosis. The patient had low levels of serum immunoglobulins; the total lymphocyte count was normal as were the percentages of circulating T and B cells. Transmission electron microscopic studies demonstrated typical N. asteroides within the brain parenchyma and nonspecific inflammatory changes in the central nervous system. The findings suggest that humoral immunity may play a major role in the host defense of patients with this disease.