Av. Ipiranga, 6681-12C, Sala 172, Porto Alegre, 90619-900, RS, Brazil.
J Rheumatol. 2012 Jan;39(1):6-9. doi: 10.3899/jrheum.110052. Epub 2011 Oct 15.
Rheumatoid arthritis (RA) is a disease with unknown etiology but it is probably multifactorial. RA susceptibility is related to genetic, hormonal, immunologic, and environmental factors. Mannose-binding lectin (MBL) is an important protein of the human innate immune system, encoded by the MBL2 gene. Polymorphisms in MBL2 were associated with several diseases, and may be an important factor in RA susceptibility. We analyzed 3 MBL2 gene polymorphisms in 322 Brazilian patients with RA and 345 ethnically matched healthy controls.
MBL2 gene variants were analyzed through polymerase chain reaction sequencing.
Considering MBL2 B, C, and D alleles separately, a significant difference in both genotypic and allelic frequencies, particularly concerning frequency of the C allele, was observed comparing European-derived and African-derived individuals (European-derived patients 0.022 vs African-derived patients 0.205; European-derived controls 0.029 vs African-derived controls 0.144; both p < 0.001). We also analyzed MBL2 genotype in relation to extraarticular manifestations. Considering MBL2 variants together, we found an increased frequency of the OO genotype among patients with rheumatoid nodules (p = 0.031), although this association lost significance after Bonferroni correction.
Our findings suggest an association of MBL2 genotypes with some clinical manifestations of RA, but more studies are needed to clarify the actual role of MBL in RA.
类风湿关节炎（RA）病因不明，但可能是多因素的。RA 易感性与遗传、激素、免疫和环境因素有关。甘露糖结合凝集素（MBL）是人类先天免疫系统的重要蛋白，由 MBL2 基因编码。MBL2 基因多态性与多种疾病相关，可能是 RA 易感性的重要因素。我们分析了 322 例巴西 RA 患者和 345 名种族匹配的健康对照者的 3 个 MBL2 基因多态性。
通过聚合酶链反应测序分析 MBL2 基因变异。
分别考虑 MBL2 B、C 和 D 等位基因，在比较欧洲裔和非洲裔个体时，无论是基因型还是等位基因频率都存在显著差异，尤其是 C 等位基因的频率（欧洲裔患者 0.022 比非洲裔患者 0.205；欧洲裔对照组 0.029 比非洲裔对照组 0.144；均 p<0.001）。我们还分析了 MBL2 基因型与关节外表现的关系。综合考虑 MBL2 变异，我们发现类风湿结节患者 OO 基因型的频率增加（p=0.031），尽管在 Bonferroni 校正后该关联失去了意义。
我们的研究结果提示 MBL2 基因型与 RA 的某些临床表现相关，但需要进一步研究以阐明 MBL 在 RA 中的实际作用。
