Mannose-binding lectins and human ficolins are pattern-recognition proteins involved in innate immunity. A role for MBL2 and FCN2 gene polymorphisms in the pathogenesis of recurrent severe streptococcal infections and rheumatic carditis has been suggested.
The aim of this study is to evaluate the presence of MBL2 and FCN2 gene polymorphisms (SNPs) in children with a history of rheumatic fever (RF) and to investigate their possible role in RF clinical presentation and disease course.
A total of 50 Caucasian patients with RF were recruited with a control group of 52 healthy children. DNA was extracted for analysis of MBL2 gene (exon 1, codons: 52, 54, and 57) and FCN2 gene (promoter region at position -986, -602, and -4).
The FCN2 AG genotype at the -986 position was more frequently observed in patients, as compared to healthy subjects (p = 0.006); furthermore, the A allele was identified as a possible risk factor for the development of RF (OR = 7.14, CI: 2.439-20.89). Conversely, the GG genotype at the same position was observed more frequently in the control group and can be considered a protective factor for the development of the disease (p = 0.001, OR = 8.37, 95% CI: 2.763-25.33). In addition, the FCN2 GG and AG genotypes in the -4 position were also found to be protective factors for the development of RF and for carditis respectively (OR = 3.32, CI: 1.066-10.364; OR = 0.15, 95% CI: 0.037-0.566). Finally, the AA genotype in the -602 position was associated with a late onset of RF (p = 0.006). The analysis of the MBL2 gene only resulted in a higher frequency of the AA genotype on position 57 in controls as compared to patients (p = 0.025).
This is the first study evaluating the FCN2 gene polymorphisms in patients with RF and rheumatic carditis finding a protective effect of -986 GG and -4 GG genotypes in the development of RF and the -4 AG genotype for the development of carditis. Our data do not support a possible role for MBL2 polymorphisms in the pathogenesis and in the clinical manifestations of RF.