POLYMORPHISM OF THE LMP2 GENE AND DISEASE PHENOTYPE IN ANKYLOSING-SPONDYLITIS - NO ASSOCIATION WITH DISEASE SEVERITY

Although a number of reports have now described an association between polymorphism of the LMP2 gene and disease phenotype in HLA-B27 positi ve individuals with ankylosing spondylitis (AS), some describe associa tions with acute anterior uveitis, others with juvenile onset disease, and one report provides no association, A recent study describes yet a further association with disease severity in patients with juvenile rheumatoid arthritis, We therefore hypothesized that the discrepant fi ndings in adult disease may be a reflection of an underlying associati on with disease severity, Our study population consisted of 100 HLA-B2 7 positive Caucasians with AS of ten or more years duration, Clinical assessment of disease severity was based on a metrology index scoring five measurements, the modified health assessment questionnaire for th e spondyloarthropathies, and a disease activity index consisting of a visual analog scale to score the amount of pain, stiffness and fatigue . LMP2 genotypes were assigned following polymerase chain reaction amp lification from genomic DNA and restriction enzyme digestion with CfoI . Despite confirmation of a significantly higher prevalence of the LMP 2 BE genotype in AAU positive (66.0%) versus AAU negative (45.2%) pati ents (P < 0.05), we observed no association between LMP2 genotypes and any of the indices of disease severity. Furthermore, although a signi ficant association was noted between the presence of peripheral synovi tis and the functional index score (P < 0.05), a history of AAU was no t associated with more severe disease. Our data is thus internally con sistent in demonstrating no association between LMP2 genotypes and eit her disease severity or peripheral arthritis, and supports the notion that polymorphism of LMP2 primarily influences the development of AAU and not some other phenotype of AS.