Predictors of atopic dermatitis phenotypes and severity: roles of serum immunoglobulins and filaggrin gene mutation R501X

Abstract

Background: Atopic dermatitis (AD), the most common chronic relapsing skin condition of infancy and childhood, is a complex multifactorial disease, which arises from the interaction between strong genetic and environmental factors.

Objective: To investigate the roles of several factors on the severity of AD including FLG R501X gene mutation, serum immunoglobulin (Ig) levels, atopy and accompanying allergic disorders.

Method: Children were genotyped for the mutation in FLG R501X gene. Serum levels of major Ig isotypes, atopy and accompanying allergic disorders were assessed.

Results: Study group consisted of 49 patients (M: 26, F: 23) with a mean age of 4.9±3.6 years and control group consisted of 50 children (M: 30, F: 20) with a mean age of 3.8±2.8 years. Genotyping of R501X mutation revealed risk alleles in none of the children in study group or control group. IgG z-scores were significantly higher in patients with AD compared to controls (-0.97±1.13 vs 1.48±1.02, p=0.026). There was a positive trend in IgG z-scores and a negative trend in IgA z-scores across the severity of AD. History of recurrent infections was significantly associated with asthma and/or AR (47.8% in patients with asthma/AR vs 3.8% in those without). Children with low IgG or IgA levels presented at an earlier age with lower rates of atopy and mild type AD.

Conclusion: In a sample of Turkish children, FLG R501X genotyping revealed no risk alleles in variable severities of AD or healthy controls. Our data suggest that IgG and IgA levels might have a role in phenotypic features of AD in terms of severity and atopic sensitisation.