Defects in sera from acquired immunodeficiency syndrome (AIDS) patients and from non-AIDS patients with Mycobacterium avium infection which decrease macrophage resistance to M. avium.

Some characteristics of the sera and macrophages (MP) of human immunodeficiency virus (HIV)-infected patients which might contribute to their unusual susceptibility to Mycobacterium avium infection were studied. Cultures of patient peripheral blood MP in medium supplemented with their sera or normal subject sera were infected with M. avium and compared with similar cultures of normal MP. Intracellular mycobacterial replication was measured in the infected MP by CFU counts of the bacteria made from lysed samples of the MP at 0, 4, and 7 days after MP infection. Sera from patients with chronic granulomatous infection with M. avium, but no HIV infection, also were studied. The sera from all of the patients with chronic granulomatous infection and from several HIV-infected patients were deficient or lacking in an inhibitor that in normal serum acts within normal MP to suppress intracellular growth of M. avium. Most of the HIV-infected patients also had MP that were abnormally permissive for M. avium because they responded poorly to the serum inhibitor. Elucidation of these associated defects in native defenses against M. avium may result in better prevention and therapy of M. avium infections.