ObjectiveTo compare the immunologic state of 44 pediatric patients with cystic fibrosis (CF) with a control group consisting of 16 healthy individuals. MethodsCF patients aged 3 to 12 years with moderate to good clinical score were selected for the study. Erythrocytic glutathione, production of reactive oxygen species, cytokines (TNF-a, IFN-g, IL-8, IL-6, IL-10) in peripheral blood mononuclear cells cultures under spontaneous and BCG- or PHA-stimulated conditions, serum concentrations of TGF-b2, IgA, IgG, IgM, IgE, and salivary IgA were evaluated. ResultsThe spontaneous production of TNF-a, IL-6, and IL-10, the PHA-stimulated production of IL-6, and the serum TGF-b2, IgA, and IgG were increased in samples from CF patients. Healthy subjects had a higher production of TNF-a in response to BCG. ConclusionAlthough CF patients appeared clinically stable, the results of their peripheral blood examinations demonstrated an impact on the immune system.