MBL is one of the most important constituents of the innate immune system [10
]. Many studies have reported a deficiency of MBL in different populations [1
]. This is the first investigation of an association between MBL polymorphisms and JIA. Our study showed the genotypic and allelic frequencies in codon 54 were consistent with previous reports from Hong Kong and Europe [6
]. Our study did not find a codon 57 mutation. Similar results were reported in Japanese and Korean populations, although codon 57 mutations were found in 50–60% of African populations [12
]. The different distribution of genotypic and allelic frequencies in different populations might exist as a result of ethnic difference, in addition to migration [14
JIA is a common autoimmune disease, and infection has a role in its etiology [15
]. We recognize that the enhanced risk of the development of recurrent infection, in addition to systemic lupus erythematosus triggered by complement pathway deficiency states, indicates the importance of the complement system in the protection against disease [5
]. Studies have shown that the MBL pathway is an independent pathway of complement activation [2
]. Mutation and deficiency of the MBL codon could impair the ability of pathogen or immune-complex clearance, facilitating the development of autoimmunity [17
]. Therefore, we hypothesize that opsonization dysfunction of the complement system caused by MBL gene mutation is involved in the immune response to infection. However, the polymorphism of MBL did not seem to be associated with JIA or any of its subgroups in our study. In addition, no significant differences were found in the number of patients with heterozygous or homozygous mutations of codon 54 in patients with JIA who were positive or negative for RF or ANA.
JIA represents a heterogeneous group of chronic arthritis in children, with variable presentations and courses. Although the etiology of JIA is still unknown, the involvement of diverse HLA-DRB1 alleles (such as DRB1*03, DRB1*04, DRB1*08, DRB1*09, DRB1*15) has been well established by many reports [19
]. Moreover, it is thought that MBL deficiency is not an independent trigger for infection and autoimmune disease. MBL polymorphisms are supposed to have a synergistic effect on the susceptibility to disease [21
]. Our study seems to rule out a direct association between MBL gene polymorphisms and JIA. Because this study included a small number of subjects, further research in large cohorts of patients should be carried out to reach a conclusion.