Variant mannose-binding lectin 2 genotype is a risk factor for reactive systemic amyloidosis in rheumatoid arthritis.
OBJECTIVE
The aim of this study was to investigate whether polymorphism of the mannose-binding lectin 2 (MBL2) gene is related to the occurrence of systemic AA amyloidosis in patients with rheumatoid arthritis (RA).


METHODS
MBL2 structural gene polymorphisms at codon 52 (CGT-->TGT, Arg-->Cys; D), codon 54 (GGC-->GAC, Gly-->Asp; B) and codon 57 (GGA-->GAA, Gly--> Glu; C), and MBL2 promoter region polymorphism at position -221 (G-->C) were examined in 57 patients with RA complicated by biopsy-proven reactive amyloidosis and 51 control RA patients without amyloid.


RESULTS
A strong association was found between the presence of a structural MBL2 gene variant O (B, D or C) and the occurrence of amyloidosis in RA patients: 29 of 57 (50.9%) of the RA patients with amyloid had a variant allele compared with 12 of 51 (23.5%) of the RA patients without amyloid (OR 3.37, 95% CI 1.47-7.72; P = 0.004).


CONCLUSIONS
We conclude that variant MBL2 structural genotype constitutes a significant risk factor for reactive amyloidosis in RA and that the increased risk is probably related to MBL-mediated impairment of mononuclear phagocyte function.
Maury
C P J
CP
Department of Medicine, University of Helsinki, Helsinki, Finland. peter.maury@hus.fi
Aittoniemi
J
J
Tiitinen
S
S
Laiho
K
K
Kaarela
K
K
Hurme
M
M
D000328:Adult; D000368:Aged; D000686:Amyloidosis / Q000235:genetics*; D001172:Arthritis, Rheumatoid / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006801:Humans; D008107:Liver Diseases / Q000235:genetics*; D008297:Male; D037601:Mannose-Binding Lectin / Q000235:genetics*; D008875:Middle Aged; D011110:Polymorphism, Genetic / Q000235:genetics*; D012307:Risk Factors
C445619:MBL2 protein, human; D037601:Mannose-Binding Lectin