Is there an association between MBL2 gene polymorphisms and infection susceptibility in patients with systemic lupus erythematosus? An exploratory study in Mexican mestizos

Introduction

Low mannose-binding lectin (MBL) concentrations in serum are due mainly to the presence of three punctual mutations in the coding region of the MBL2 gene. SLE patients, who are homozygous for MBL allele variants, have a significantly greater risk of developing infections. With the purpose of examining the association of MBL locus haplotypes with disease activity and past history of infection in SLE, we studied a group of patients treated in the Rheumatology Outpatient Clinic of the UANL University Hospital.

Objective

Determine the prevalence of MBL2 locus haplotypes and the causal associations between MBL2 locus haplotypes and SLE determining the Hardy–Weinberg law for specific genotypes in both groups of study.

Materials and methods

An observational, cross-sectional, retrospective study was performed. Hardy–Weinberg equilibrium for genotypic frequencies was proven with the X² test. The risk of lupus associated with MBL2 genotypes as a genetic factor and the strength of the association of the genotypes with the frequency of clinical characteristics was estimated by calculation of odds ratio with a 95% confidence interval. Statistical significance was taken as a value of P < .05.

Results

The findings suggest potential genetic associations between allelic systems and the risk of SLE. A relationship was found regarding the MEX-SLEDAI index, as well as the number of infections among patients with differences in structural gene polymorphisms and promoter gene polymorphisms.

Conclusions

There are significant differences in the polymorphisms of the promoter region regarding the risk for developing SLE.