A study on rIL-4 and IFN-gamma regulating IgE synthesis in bronchial asthma patients.

OBJECTIVE: To investigate the cytokines responsible for pathophysiology of asthma. METHODS: In vitro effects of recombinant interleukin-4 (rIL-4) and interferon-gamma (IFN-gamma) on synthesis of immunoglobulin E (IgE) by peripheral blood mononuclear cells (PBMC) were studied in 30 asthmatic patients and 25 normal controls. RESULTS: Spontaneous IgE synthesis by PBMC significantly increased in patients with asthma compared with the controls (t = 4.471, P < 0.001). Although the maximum amounts of IgE synthesis using PBMC after stimulation with rIL-4 were almost the same in the patients with asthma and in the controls (P > 0.05), the enhancement rate of rIL-4-induced IgE synthesis was lower in the asthma patients than in the controls (t = 4.6719, P > 0.005). IFN-gamma suppressed both spontaneous and rIL-4-induced IgE synthesis by PBMC in the asthma patients. The suppressive effect on IgE synthesis was more prominent in the patients with asthma than in the controls (t = 7.1833, P < 0.001). CONCLUSIONS: Asthma attacks are related to IgE-dependent trigger mechanism. The imbalance of IL-4 and IFN-gamma in vivo is the cause of elevated IgE than can produce mediators release and asthma attacks. IFN-gamma can inhibit IgE synthesis, so IFN-gamma may be a new approach to the treatment of asthma.