Recurrent respiratory infections and phagocytosis in childhood.

Background: About 10% of pre-school children has recurrent respiratory infections (RRI), which could be related to environmental and/or immunological factors. The aim of the present study has been to evaluate the impact of phagocytosis (FAG) and reactive oxygen intermediates (ROI) production deficiencies on pediatric RRI by the measurement of FAG and ROI activity of the polymorphonuclear neutrophils.

Methods: Serum immunoglobulins, IgG subclasses, lymphocytic subpopulations, FAG and ROI tests were measured in 90 children with RRI, in a moment of well-being and off all medications for at least 4 weeks. FAG and ROI tests were also measured in 19 healthy children.

Results: FAG (91.4 +/- 11.5%) and ROI (81.8 +/- 17.5%) of patients resulted in significantly decreased measurements compared to the control values (95.2 +/- 1.8% and 89.7 +/- 4.8%, respectively). No significant difference was manifest between the mean values of FAG and ROI tests among the patients when they were divided for age (above and below 6 years). A significant decreased likelihood of abnormal ROI (odds ratio, 0.3; 95% confidence interval, 0.07-0.97) was found in the patients with low IgA.

Conclusions: The authors' results permit only to suppose an etiological role of FAG and ROI deficiencies of polymorphonuclear neutrophils in the genesis of pediatric RRI, irrespective of the age of the patients, and further studies are necessary for confirmation.