Effect of smoking on atopic predisposition and sensitisation to allergens

Previous studies elsewhere have shown higher serum immunoglobulin E (IgE) levels in smokers and an association between smoking and sensitisation to allergens. Such information is not available for Indian population. Hence, the present study was carried out to evaluate the effect of smoking on atopic predisposition and sensitisation to aeroallergens.

A total of 70 subjects were included in the present study comprising of 25 smokers, 22 reformed smokers and 23 non-smokers. Absolute eosinophil count (AEC), serum total IgE levels and skin prick test (SPT) against common aeroallergens were performed in all the subjects along with breath carbon monoxide (CO) levels and pulmonary function tests.

Smokers showed significantly higher serum total IgE levels (328.80 +/- 161.82 IU/mL) as compared to reformed smokers 177.27 +/- 86.47 IU/mL) and non-smokers (29.56 +/- 9.75 IU/mL). A number of subjects among smokers and reformed smokers elicited positive SPT reactions to various allergen extracts. Non-smokers did not show any significant positive skin reaction. The AECs were slightly higher in smokers (350 +/- 1145.61/mm3) as compared to reformed smokers (305 +/- 146.33/ mm3). Breath CO was considerably higher (greater than three times) in smokers than reformed smokers. However, reformed smokers showed greater airways obstruction than smokers. The former also had higher Brinkman index (646.81 +/- 392.32) as compared to the latter (448.36 +/- 279.86).

Smokers had significantly higher IgE serum levels than reformed smokers and non-smokers. Smoking seems to induce an atopic orientation and allergen sensitisation in individuals.