No primary association between LMP2 polymorphisms and extraspinal manifestations in spondyloarthropathies.

OBJECTIVE To investigate the potential role of the HLA-linked LMP2 (low molecular weight protein) gene polymorphisms in conjunction with DR4 and DR7 on extraspinal disease manifestations in HLA-B27 positive patients with spondyloarthropathy. METHODS 172 patients with spondyloarthropathy, 46 healthy, HLA-B27 positive blood donors, and 99 unrelated controls were typed for HLA-class I and II antigens. LMP2 alleles were determined by polymerase chain reaction and subsequent restriction enzyme digestion. RESULTS There were statistically non-significant increases of DR4 and DR7 in spondyloarthropathy subjects. However these differences did not relate to specific extraspinal manifestations. There were no significant differences in the LMP2 genotype distribution in the disease groups. All differences in LMP2 genotype frequencies disappeared when correcting for DR4, which was in linkage disequilibrium with the LMP2B allele. CONCLUSIONS There is no independent association between LMP2 genotypes and the occurrence of uveitis or peripheral arthritis in HLA-B27 positive subjects with spondyloarthropathy. DR4 and DR7 do not contribute to these disease manifestations.