Defective leukocyte interferon response in children with recurrent infections accompanied by arthralgia.

Children with recurrent and/or unusually severe infections were investigated for possible defects in the interferon (IFN)-natural killer (NK) cell system. Two series, each of 13 children, were examined, one in 1982 and one in 1983. Healthy children, seven in 1982 and eight in 1983, served as controls. Peripheral blood mononuclear leukocytes were examined for IFN production induced by the IFN-alpha inducers Sendai virus and Escherichia coli and by the IFN-gamma inducers Concanavalin A and Lens culinaris lectin. None of these inducers discriminated patients from controls. However, the bacteria Staphylococcus aureus Cowan I (SACol), inducers of atypical IFN in null lymphocytes, yielded significantly lower IFN production in infection-prone children than in controls, particularly in children with recurrent infections accompanied by arthralgia. No differences in basal NK activity or in the in vitro enhancement of such activity by IFN-alpha were found between patients and controls.