Aberrant expression of novel cytokine il-38 and regulatory t lymphocytes in childhood asthma

Abstract

We investigated the expression of novel anti-inflammatory interleukin (IL)-38 and regulatory T (Treg) lymphocytes in childhood asthma patients. The protein and mRNA expression level of IL-38, periostin, peripheral CD4+ CD25+ CD134+ T lymphocytes as well as CD4+ CD25high FoxP3+ and CD4+ CD25high CD127- Treg lymphocytes from 40 asthmatic patients and 20 normal control (NC) subjects were studied using ELISA, qPCR and flow cytometry. Serum and supernatant cytokines/chemokines were determined by multiplex assay. Serum IL-38, IL-5, IL-17, IL-6, interferon-ã, periostin, IL-1β and IL-13 concentrations were significantly higher in asthmatic patients with or without steroid treatment than those in controls (all p < 0.05). The percentages of both CD4+ CD25high FoxP3+ and CD4+ CD25high CD127? Treg lymphocytes were markedly decreased in asthmatic patients with and without steroid treatment than those in controls (all p < 0.05). The elevated IL-38 concentration negatively correlated with the percentage of Treg lymphocytes in asthmatic patients with high level (>40 ng/mL) of periostin (p < 0.05). Although the comparable mRNA levels of IL-38 and its receptor IL-36R were found between patients and controls, the mRNA level of IL-38 positively correlated with IL-36R and negatively correlated with IL-10 in all asthmatic patients (both p < 0.05). The percentage of CD4+ CD25+ CD134+ activated T lymphocytes was also significantly higher in asthmatic patients with steroid treatment than those in controls (p < 0.05).This cross-sectional study demonstrated that the overexpression of circulating IL-38 may play a role in the immunopathogenesis in asthma.