Mannose-binding lectin and susceptibility to infection in Chinese patients with systemic lupus erythematosus.
OBJECTIVE
To test the hypothesis that low serum mannose-binding lectin (MBL) levels, as a result of the single-nucleotide polymorphisms in the promoter region (-221 X/Y) and exon 1 (codon 54 A/B) of the MBL2 gene, predispose to infection in Chinese patients with systemic lupus erythematosus (SLE).


METHODS
Two hundred forty-five patients with SLE were prospectively followed for the development of major infective episodes that required hospitalization and antibiotic treatment during 1992-2005. MBL genotypes were determined by polymerase chain reaction and serum MBL levels were measured by ELISA.


RESULTS
In total, 254 major infections developed in 130 patients. Serum MBL levels were shown to correlate inversely with the number of bacterial infections (r = -0.13, p = 0.03). The distribution of MBL genotypes was similar in patients with and without major infection (p = 0.84). Patients with major infection also had more major lupus exacerbations that required daily prednisolone dose > or = 15 mg. Logistic regression showed that log MBL level (odds ratio 0.516, 95% confidence interval 0.305-0.873; p = 0.01) and major lupus exacerbation (OR 1.382, 95% CI 1.154-1.654; p < 0.001) were independent risk factors to major bacterial infection after adjustment for age and disease duration. Multiple regression analysis showed an increase in risk of bacterial infection by 34.2% for every decrease in serum MBL level by one log, and by 22.8% for each increase in number of major lupus exacerbations.


CONCLUSIONS
Low serum MBL level predisposes Chinese patients with SLE to more major infections, in particular bacterial ones.
Mok
Mo Yin
MY
Department of Medicine, Queen Mary Hospital, Hong Kong. mymok@netvigator.com
Ip
W K Eddie
WK
Lau
Chak Sing
CS
Lo
Yi
Y
Wong
Wilfred H S
WH
Lau
Yu Lung
YL
D000293:Adolescent; D000328:Adult; D000368:Aged; D001424:Bacterial Infections / Q000208:ethnology / Q000276:immunology*; D002681:China; D015331:Cohort Studies; D004198:Disease Susceptibility / Q000208:ethnology / Q000276:immunology*; D005260:Female; D005786:Gene Expression Regulation; D005838:Genotype; D006801:Humans; D016867:Immunocompromised Host / Q000276:immunology; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000150:complications* / Q000188:drug therapy / Q000208:ethnology; D008297:Male; D037601:Mannose-Binding Lectin / Q000097:blood* / Q000235:genetics; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D009894:Opportunistic Infections / Q000235:genetics / Q000276:immunology*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D011446:Prospective Studies
D007166:Immunosuppressive Agents; D037601:Mannose-Binding Lectin