Background: IL-4 is an important mediator of inflammatory cytokine derived from T helper cells and mast cells which triggers IgE synthesis. IL-4 plays an important role in allergic immune response for its ability to prevent apoptosis of T lymphocytes. IL-4 also plays a role in lymphocytes cell differentiation, cytokines and IgE production. This study aimed to evaluate the relation between the serum levels of IL-4 and IgE with disease severity in patients with allergic asthma.

Materials and Methods: In this case-control study, 110 asthmatic patients referred to Asthma and Allergy Clinic in Kashan and 70 healthy controls were randomly selected. Blood sample (5 ml) was taken from all the patients and healthy subjects and the serum levels of IL-4 and IgE were measured using the standard laboratory kits and ELISA method, respectively.

Results: The IL-4 and IgE mean levels were not significantly associated with age and sex. The mean IgE level increased from moderate to severe with increasing asthma severity (P=0.847). Moreover, the IL-4 level in patients with severe asthma was higher than the other patients (P=0.002).

Conclusion: IL-4 level was increased with increasing asthma severity, but this was not the case for IgE.