[Correlation between mannose-binding lectin gene codon 54 polymorphism and susceptibility of Kawasaki disease].

Objective: Human mannose-binding lectin (MBL) is a C-type serum lectin synthesized by the liver as an acute-phase protein. MBL can bind to glycoproteins terminated with mannose and N-acetylglucosamine present in the cell walls on a variety of microorganisms. Therefore, MBL appears to play an important role in the immune system. Low levels of MBL in human have been associated with a susceptibility to recurrent infections. MBL deficiency and low serum MBL levels are strongly associated with the presence of three point mutations at codon 52, 54 and 57 of exon 1 in the human MBL gene, and in Chinese population, the codon-54 mutation occurs at a frequency of 0.11 - 0.17. The data suggested that MBL insufficiency might also predispose to the development of autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). The possibility that Kawasaki disease (KD) is an infectious disease has been discussed and investigated for decades, in light of the implication that infections are involved in the pathogenesis of KD. It has been suggested that MBL insufficiency might predispose to the occurrence of KD. This study was aimed to investigate the genetic association of MBL codon-54 polymorphism in patients with KD, and to investigate possible associations with clinical manifestations of the disease.

Methods: There were 95 patients with KD and 160 healthy subjects in the study. The genotype of MBL gene 54 codon was detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Clinical characteristics and biochemical examination were also performed.

Results: The genotype frequency of heterozygote (GGC/GAC) was significantly higher in KD group than that in healthy subjects (45.2% vs 25.0%, P < 0.01), and the allele frequency of GAC mutation was also higher in KD patients than that in control group (0.258 vs 0.138, P < 0.01). The variant allele (GAC) was markedly associated with KD (OR = 2.18, 95% CI = 1.38 approximately 3.44, P < 0.05). But there was no significant difference in the allele frequency of GAC between patients with and without coronary artery lesion (CAL) in KD cases (0.281 vs 0.246, P > 0.05). In addition, in cases of KD, more patients carrying the variant allele (GAC) had episodes of upper respiratory or gastrointestinal infections prior to the onset of KD than wild homozygotes (P < 0.01).

Conclusion: The codon 54 polymorphism of MBL gene was associated with KD. It is possible that MBL gene codon 54 mutation might be related to the pathogenesis of KD.