Systemic salmonellosis in patients with disseminated histoplasmosis. Case for 'macrophage blockade' caused by Histoplasma capsulatum.

Five patients are described with disseminated histoplasmosis and systemic salmonellosis. Four of these patients were also immunocompromised because of the acquired immunodeficiency syndrome in two patients and renal transplantation in another two patients. Histologic studies in two patients showed histiocytes that were heavily laden with Histoplasma capsulatum yeast-phase organisms. We postulate that diffuse parasitization of the reticuloendothelial system (RES) by Histoplasma organisms may cause "RES blockade," which then predisposes to systemic salmonellosis, as reported in certain other infections and in sickle cell anemia.