Absence of interferon in sera of patients with Kawasaki syndrome.

We measured serum interferon concentrations in 42 patients with Kawasaki syndrome. The children ranged in age from 7 months to 6 years. All acute sera were obtained within 12 days of the onset of fever. Convalescent sera (illness day 19 to 56) were available from 25 of 42 patients. Sera were also obtained from 40 controls ranging in age from 2 months to 12 years. Control sera included healthy children (n = 14), children with bacterial infection (n = 10) and children with viral infection (n = 16). Sera were coded and interferon concentrations were measured blindly using human diploid fibroblast cell monolayers challenged with 10(4) plaque-forming units of vesicular stomatitis virus. Specimens from 10 of 16 patients with viral infection were positive for interferon. Three of 10 patients with bacterial infection had detectable serum interferon. No interferon was detected in specimens from the 14 healthy control children or the 42 children with Kawasaki syndrome. Despite the use of a sensitive assay we were unable to detect interferon in the sera of patients with Kawasaki syndrome.