Lowered yields of virus-induced interferon production in leukocyte cultures and risk of recurrent respiratory infections in children

Objective: To study the correlation between the yield of virus-induced inte rferon (IFN) production in leukocyte cultures and the risk of recurrent res piratory infections. Methods: A sample of 71 consecutive children enrolled in the Finnish Otitis Media Cohort Study were selected. Children suffering from frequently recurring respiratory infections (FRRIs) were defined as th e highest quintile of the entire cohort of 329 children, as regards the num ber of upper respiratory infections (URIs) and/or episodes of acute otitis media (AOM) during the follow-up period from 2 to 24 months. Results: In th e sample of 71 children, there were 18 children with FRRI (greater than or equal to 9 URI and/or greater than or equal to 4 AOM). Leukocyte cultures, prepared from blood drawn from these 18 children at 6 months of age, produc ed lower yields of IFN than those of the remaining 53 children, when stimul ated with adenovirus (P < 0.001), coronavirus (P < 0.001) or rhinovirus (P = 0.002). The difference in IFN yields was even greater (P < 0.001 with all three viruses) if the comparison was made between children with FRRI and t hose with no or maximally one URI during the follow-up period. When the IFN production capacity induced by rhinovirus was measured at the age of 24 mo nths, a statistically significant difference between the children with FRRI and the others was also seen (P = 0.002). Influenza A virus-induced IFN pr oduction capacity did not differ between the groups at either age (P = 0.20 9). Conclusions: Lowered IFN responses in children suffering from recurrent URIs and/or AOM may, in a subgroup of the children, be due to a genetic pr operty of the child. However, because of the great interindividual variatio ns, we cannot use the IFN production capacity as such for prediction of for thcoming respiratory infections and/or otitis media. (C) 1999 Elsevier Scie nce B.V. All rights reserved.