Overexpression of IL-10 mRNA in gut mucosa of patients with allergic asthma

Because an airway-like inflammation has been reported in the gut of asthmat ic patients, we sought to examine the expression of immunoregulatory cytoki nes like IL-4, IL-10, and IL-13 by gut mucosa, To establish this, we initia ted this study to examine mRNA expressions of IL-4, IL-10, and IL-13 in duo denal mucosa from patients with asthma. Duodenal biopsy specimens were obta ined from 20 asthmatic patients (10 allergic, 10 nonallergic) and 8 healthy controls. Cytokine mRNA was quantified with reverse transcriptase-competit ive PCR, and results were expressed in proportion to the number of p-actin mRNA in the same sample. IL-10 and IL-4 mRNA were detectable in all patient s, whereas no IL-13 mRNA was detected. IL-IO mRNA concentrations were signi ficantly higher in allergic subjects with asthma than in control subjects a nd nonallergic subjects with asthma, No significant difference was observed for IL-4. IL-IO mRNA expression was not related to asthma severity, FEV,, blood eosinophilia, or IgE levels. Our results support the hypothesis that IL-10 overexpression may counterbalance the effects of proinflammatory cyto kines and mitigate the inflammatory reaction found in gut mucosa of subject s with asthma.