[Association of IL13 rs1800925 and rs1881457 variants with severe asthma in a population from Western Mexico].

Background: Asthma is a chronic inflammatory disease with variable airflow obstruction. Severe asthma (310% of cases) requires high-dose corticosteroids, increasing the risk of exacerbations. The IL13 rs1800925 and rs1881457 variants, involved in the regulation of inflammation, have been associated with asthma severity in various populations, but their impact in Mexico has not been studied.

Objective: To evaluate the association of the IL13 rs1800925 and rs1881457 variants in patients with severe asthma.

Methods: One hundred patients with severe asthma and 150 healthy controls were analyzed. DNA was extracted and quantified for genotyping using allelic discrimination. Lung function, IgE levels, hospitalizations, symptoms, medications, and allergen exposure were assessed. Haplotypes and linkage disequilibrium (LD) were calculated.

Results: There were no significant differences in allele/genotype frequencies between groups. A strong LD was observed between rs1800925 and rs1881457 (D=0.83, r²=0.77, p<0.05). 77% had an eosinophilic Th2 endotype, 70% had aeroallergen allergy, and 54% had insufficient disease control. Women used more reliever medication and had more nighttime symptoms (p<0.05).

Conclusion: The variants exhibit a strong LD but do not show a significant association with AG in this population. The high prevalence of the eosinophilic Th2 endotype and sensitization to aeroallergens reinforce the role of allergic inflammation in the disease. Furthermore, sex differences suggest a greater incidence in women, which could influence the clinical management of AG. Larger studies are needed to confirm these findings.