Background/aims: Asthma is a multifactorial disease influenced by both genetic and environmental factors. This study aimed to investigate the association between the IL4 gene polymorphism (rs2243250) and asthma susceptibility, along with serum IL-4 levels. Additionally, it explored Mycoplasma pneumoniae infection as a potential risk factor for asthma.
Methods: A total of 118 individuals were enrolled, including 60 asthma patients and 58 healthy controls. Genotyping for IL4 rs2243250 was performed using allele-specific PCR (AS-PCR). Previous Mycoplasma pneumoniae infection was assessed serologically, and serum IL-4 levels were measured using ELISA.
Results: No significant differences were observed between groups in terms of age, sex, or residence. Smoking (OR: 7.85, P = 0.001) and family history of asthma (OR: 5.33, P = 0.004) were identified as significant risk factors. Mycoplasma pneumoniae infection was significantly more prevalent in asthma patients (41.7%) than in controls, with a strong association with asthma risk (OR: 8.75, P < 0.0001). Genotype frequencies of rs2243250 differed significantly: CC (36.7% vs. 68.9%), CT (41.7% vs. 24.2%), and TT (21.6% vs. 6.9%) in patients versus controls, respectively. The T allele was more frequent among patients (42.5%) than controls (18.97%), increasing asthma risk (OR: 3.16, P = 0.0001). Both CT (OR: 3.25) and TT (OR: 5.91) genotypes were strongly associated with asthma. Moreover, individuals with the TT genotype had significantly higher serum IL-4 levels (P < 0.001).
Conclusion: The IL4 rs2243250 polymorphism is associated with increased asthma susceptibility and elevated serum IL-4 levels in the Iraqi population. Mycoplasma pneumoniae infection also appears to be a significant contributing factor. Larger-scale studies are warranted to confirm these findings and further explore the role of this infection in asthma pathogenesis.
Keywords: Interleukin-4 ; Rs2243250 ; Single Nucleotide Polymorphism ; Asthma ; Mycoplasma pneumoniae.
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