Interferon production in children with undue susceptibility to infections.

The interferon-producing ability of peripheral blood mononuclear leukocytes obtained from children with undue susceptibility to infections was investigated. Patients were grouped according to three clinical patterns, i.e. children with mainly upper respiratory tract infections, with lower respiratory tract infections and with frequent middle ear infections. There was no evidence of impaired mean interferon-alpha responses to the inducers Sendai virus and beta-hemolytic Group G streptococci in patients compared with control children, and there were no differences in this respect between the patient subgroups. A tendency to increased Concanavalin A-induced interferon-gamma production was seen in patients, particularly those with middle ear infections. Leukocytes from patients displayed a higher proliferative response to the T cell mitogens Concanavalin A and Lens culinaris lectin. In a minority of patients (5/28) reproducibly low interferon responses to Sendai virus were found but only one of these patients showed a response below the -2 SD limit for the control group. The results therefore indicate no major defects in the interferon responses of infection-prone children, and at the most suggest that a minority of such patients may be low responders to a viral interferon inducer.