Mannose-binding lectin polymorphisms are not associated with rheumatoid arthritis - confirmation in two large cohorts

Objectives. In RA, conflicting results have been described on the association between genotypes of the complement factor mannose-binding lectin (MBL) and disease susceptibility and severity. This might be due to underpowerment of previous research work and the fact that no confirmation cohorts were used. Therefore a different approach is warranted. Methods. MBL2 gene polymorphisms were determined in two RA cohorts (378 and 261 cases) and 648 controls. Considering MBL polymorphisms, cases and controls were categorized in groups of high, intermediate and low MBL production. The total sample size allows detection of a potential association between RA susceptibility and MBL groups with an odds ratio of 1.37 (alpha < 0.05; 1-beta > 0.8). Disease severity as defined by the need for anti-TNF therapy was also analysed for possible associations with MBL groups. Results. There was no difference in the frequencies between MBL genotypes of RA cases and controls that are associated with high (cases 54.4, controls 57.0), intermediate (cases 28.9, controls 27.5) or low (cases 16.7, controls 15.5) MBL production. Furthermore, there was no association between MBL groups and disease severity. Conclusions. MBL genotype groups are not associated with RA disease susceptibility or severity in this large study including a confirmation cohort. Compared with previous smaller studies these results add to more definite conclusions.