Autoantibodies against interferon-γ are associated with severe disseminated opportunistic infection, but their importance and prevalence are unknown.
We enrolled 203 persons from sites in Thailand and Taiwan in five groups: 52 patients with disseminated, rapidly or slowly growing, nontuberculous mycobacterial infection (group 1); 45 patients with another opportunistic infection, with or without nontuberculous mycobacterial infection (group 2); 9 patients with disseminated tuberculosis (group 3); 49 patients with pulmonary tuberculosis (group 4); and 48 healthy controls (group 5). Clinical histories were recorded, and blood specimens were obtained.
Patients in groups 1 and 2 had CD4+ T-lymphocyte counts that were similar to those in patients in groups 4 and 5, and they were not infected with the human immunodeficiency virus (HIV). Washed cells obtained from patients in groups 1 and 2 had intact cytokine production and a response to cytokine stimulation. In contrast, plasma obtained from these patients inhibited the activity of interferon-γ in normal cells. High-titer anti–interferon-γ autoantibodies were detected in 81% of patients in group 1, 96% of patients in group 2, 11% of patients in group 3, 2% of patients in group 4, and 2% of controls (group 5). Forty other anti-cytokine autoantibodies were assayed. One patient with cryptococcal meningitis had autoantibodies only against granulocyte–macrophage colony-stimulating factor. No other anti-cytokine autoantibodies or genetic defects correlated with infections. There was no familial clustering.
Neutralizing anti–interferon-γ autoantibodies were detected in 88% of Asian adults with multiple opportunistic infections and were associated with an adult-onset immunodeficiency akin to that of advanced HIV infection.