Role played by Th2 type cytokines in IgE mediated allergy and asthma

Abstract

Objective: Recent evidence suggest that allergen type 2 helper T cells (Th2) play a triggering role in the activation/recruitment of IgE antibody producing B cells, mast cells and eosinophils. Reduced microbial exposure in early life is responsible for a shift of Th1/Th2 balance in the immune system towards the pre-allergic Th2 response. The Th1 predominantly produce IFNgamma and delayed type hypersensitivity while Th2 secrete IL-4, IL-5, IL-6, IL-13 and regulate B cell and eosinophil mediated responses. To assess regulatory changes in the immune system, in patients with allergy and asthma, we studied the cytokine profile in serum in comparison with normal healthy controls.

Patients and methods: A total of 170 patients with various allergies and asthmatic conditions were studied, for cytokines in the serum by ELISA using kits from Immunotech, and analyzed to identify the triggering factors or main contributors towards allergy and asthma.

Results: Our study showed increase in the levels of IL-4, IL-5 and IL-6 in all groups which were non- significant. But the levels of IL-10, IL-13 and TNF alpha were highly significant. Besides, we found correlation of GM-CSF with IL-10. Significant correlation with different cytokines was observed. Most of these patients showed increase in IgE levels.

Conclusions: This study gives a better understanding of how cytokines are the mediators of balance of Th1 and Th2 immune responses and IgE synthesis is controlled by cytokines. Further studies will eventually lead to improved treatment strategies in the clinical management of IgE mediated allergy.

Keywords: Allergy; Type 2 helper T cells; asthma; cytokines.

Figure 1

Levels of cytokines in different allergic conditions