MBL2 gene polymorphisms and its relation to infection in Brazilian systemic lupus erythematosus patients: A 10-years follow-up study

Systemic lupus erythematosus (SLE) is a multifactorial disease and MBL2 genetic variants, which are associated to differential peripheral MBL levels, potentially affect its etiology and increase infection risk in this population.To evaluate the potential association of MBL2 polymorphisms of the coding and promoter gene region and haplotypes on hospitalization, number of admission and days of admission for major infection causes in Brazilian SLE patients. Methods: 325 SLE patients from a southern Brazilian outpatient SLE clinic were genotyped in 2006 for MBL2 gene polymorphisms from coding and promoter region (rs1800450, rs1800451, rs5030737, rs11003125, and rs7096206) and followed until 2016. Clinical and laboratory data from each patient were obtained and information regarding the need for hospitalization, the number of admissions and number of days admitted for infection treatment were compiled and compared with MBL2 gene polymorphisms and haplotypes. A linear regression analysis was constructed considering the variables of bivariate which demonstrated an association (p<0.05) and variables which had a theoretical basement.No difference was found in polymorphism prevalence when comparing the group that was admitted for infection treatment and the group who did not. Allele C, and haplotypes LY and HY correlated with more infection hospitalizations [wild-type homozygosis for C: 2 (IQR 1-3), heterozygosis for C: 3 (IQR 2-6) p=0.038; LY 2 (IQR 1-3) p=0.049; HY 2 (IQR 1-3) p=0.005] and haplotype HY carriers stayed fewer days in hospital for infection treatment: 18 (IQR 10-38) p=0.041. When linear regression was applied HY associated with shorter admission time for infections (-18.11 days, p=0.021) and HY (-1.52 admission, p 0.001) carriers with older age at diagnosis had less admissions for infection (HY regression model: -0.42, p=0.006; LY regression model -0.04, p=0.010; -0.04, p=0.013).The presence of the HY promoter haplotype associated to fewer in hospital care for infection treatment probably due to higher MBL plasma levels. Also, HY haplotype and older age at SLE diagnosis is related to less admissions for infection. This factor should be taken into consideration, since infection is a very import cause of mortality in SLE patients being also related to aggressive immunosuppressive treatment.