title: Increased frequency of the mannose-binding lectin LX haplotype in Chinese systemic lupus erythematosus patients.
abstract: Mannose-binding lectin (MBL) is an important complement-activating protein of the human immune system. As a result of one of three structural gene mutations in exon 1 (variants B, C and D) and/or the presence of a low-efficiency promoter polymorphism, MBL deficiency may be associated with increased susceptibility to infectious diseases and to autoimmune disorders, including systemic lupus erythematosus (SLE). Using a combined approach of heteroduplex generator and polymerase chain reaction, a systematic search for mutations in exon 1 and the promoter region of the MBL gene was performed in a Chinese study population comprising 41 SLE patients and 111 healthy controls. Two alleles, a wild-type allele A and a variant allele B (a previously reported mutation of GGC to GAC at codon 54), were identified in MBL exon 1. The frequency of the B allele (0.15) was higher in the SLE patients than in the healthy controls (0.09), but the difference did not attain statistical significance (P > 0.05). However, for two polymorphisms at positions -550 and -221 in the promoter region, the frequency of the low-MBL-producing haplotype (LX) in the patients (0.2073) was significantly higher than that in the controls (0.0855) (P = 0.003, relative risk = 2.79). Our results suggest that the LX haplotype represents a strong risk factor among Chinese SLE patients. Although of lesser importance, the MBL B allele also may be a risk component in the developing process of SLE in Chinese patients.
authors.affiliation: Institute of Immunology, Tonji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Y F
authors.initials: YF
authors.lastname: Huang
authors.forename: W
authors.initials: W
authors.lastname: Wang
authors.forename: J Y
authors.initials: JY
authors.lastname: Han
authors.forename: X W
authors.initials: XW
authors.lastname: Wu
authors.forename: S T
authors.initials: ST
authors.lastname: Zhang
authors.forename: C J
authors.initials: CJ
authors.lastname: Liu
authors.forename: Q G
authors.initials: QG
authors.lastname: Hu
authors.forename: P
authors.initials: P
authors.lastname: Xiong
authors.forename: R M J
authors.initials: RM
authors.lastname: Hamvas
authors.forename: N
authors.initials: N
authors.lastname: Wood
authors.forename: F L
authors.initials: FL
authors.lastname: Gong
authors.forename: A H
authors.initials: AH
authors.lastname: Bittles
mesh_terms: D000293:Adolescent; D000328:Adult; D002681:China; D005260:Female; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000235:genetics*; D008297:Male; D037601:Mannose-Binding Lectin / Q000235:genetics*; D008875:Middle Aged
chemical_list: D037601:Mannose-Binding Lectin