Association of mannose-binding lectin 2 (rs11003125) gene polymorphism and serum levels with atopic dermatitis in Iraqi patients

Abstract

Objective: Atopic dermatitis (AD) is a chronic inflammatory skin disease with complex pathogenesis involving genetic and immune factors. This study investigated the association between the MBL2 rs11003125 polymorphism, serum mannose-binding lectin (MBL) concentrations, and AD susceptibility in an Iraqi cohort.

Methods: This case-control study included 60 clinically diagnosed AD patients and 40 age- and sex-matched healthy controls. Serum MBL levels were quantified by ELISA. Genomic DNA was extracted from blood, and the MBL2 rs11003125 polymorphism was genotyped by PCR and Sanger sequencing. Statistical analyses included chi-square, Mann-Whitney U, Kruskal-Wallis, and multivariate logistic regression.

Results: Serum MBL levels were significantly lower in AD patients (median 84.42 µg/L, interquartile range [IQR]: 42.59–139.79 µg/L) than in controls (median 147.62 µg/L, IQR: 49.65–526.49 µg/L; p = 0.005). The C allele of rs11003125 was associated with increased AD risk (odds ratio [OR] = 2.18, 95% confidence interval [CI]: 1.22–3.90, p = 0.006). In a dominant model, individuals carrying at least one C allele (GC+CC) demonstrated a 3.9-fold increased AD risk (adjusted OR = 3.9, 95% CI: 1.5–9.2, p = 0.004). Serum MBL levels showed significant genotype-dependent reduction, with the highest levels in GG (median 133.49 µg/L), intermediate in GC (median 87.58 µg/L), and lowest in CC (median 36.68 µg/L; p = 0.0004).

Conclusions: The MBL2 rs11003125 polymorphism was significantly associated with reduced serum MBL levels and conferred increased risk of atopic dermatitis in the studied Iraqi population, highlighting the role of MBL-mediated innate immunity in AD pathogenesis.