Studies on the role of CD14 polymorphism among pollen and mold induced asthmatics of kolkata, India

Background: There has been a surge in the incidence of bronchial asthma around the world especially in developing countries like India, because of many factors such as change in ambient air quality, increased air pollution, metamorphic change in living habits and lifestyle and climate. The allergens  like pollens, fungi, etc.  present in the air plays a pivotal role in pathogenesis of several allergic complaints  such as allergic rhinitis, bronchial asthma etc. Studies revealed the complex interactions of genetic and environmental factors are involved in asthma. India is the home to around 15–20 million asthmatics and asthma prevalence is increasing in India especially  in Kolkata. To provide the patients with best possible diagnosis and treatment, the identification of offending allergens are of major importance. However early detection of individuals who are genetically at risk of developing pollen and mold allergy is also an essential element to adopt effective avoidance strategies and to design appropriate therapies. As accustomed, the information in this respect is mostly available from developed and western countries while preliminary information from developing countries like India, particularly Kolkata Metropolitan areas is still fragmentary and insufficient. Therefore, present study involved identification of offending outdoor aeroallergens and also associated genetic pathway in nasobronchial asthma among Kolkata population.

Methods: Skin-prick test was done among 950 asthmatic patients against 17 common aeroallergens and total serum IgE concentration was measured. PCR-RFLP was done in patients and non-asthmatic control (n=220 in each) to characterize a functional polymorphism, C(-159)T, of CD14, a positional candidate gene for allergy. Association of genetic polymorphisms was made with Clinicopathological conditions.

Result: Present study identified Cocos as the most predominant outdoor aeroallergen in Kolkata followed by Caesalpinia and Peltophorium, all of which belong to pollen category. Patients with childhood-onset of asthma were significantly more sensitive towards aeroallergens and had significantly higher serum IgE level than that of adult-onset. No significant difference was found in distribution of SNP genotypes of CD14 among case and control. However among patients, frequency of C allele is significantly higher in childhood-onset group than that of adult-onset and concordantly in former, CC genotype was associated with significant higher level of total serum IgE than CT and TT.

Conclusion: In Kolkata, pollen is common outdoor aeroallergen and Cocos is predominant among pollens. Childhood-onset and adult-onset of asthma showed significant difference in allergen sensitivity and differential association of CD14 polymorphism might be involved in this process.