Objectives: To investigate the potential role of the HLA-linked LMP2 (low molecular weight protein) and LMP7 gene polymorphisms in conjunction with HLA class I and class II genes on the disease pattern in individuals with psoriatic arthritis (PsA).
Methods: Sixty-three patients with PsA and 99 unrelated controls were typed for HLA-class I and II antigens. LMP2 and LMP7 polymorphisms were determined by PCR and subsequent single stranded conformation polymorphism (SSCP) analysis or restriction enzyme digestion.
Results: PsA was associated with B27 (p < 0.0004), B57 (p < 0.002) and Cw2 (p < 0.008). Spondylarthritis was strongly associated with HLA-B27 (p < 0.000001), Cw2 (p < 0.0003) and DR4 (p < 0.008). For the polyarthritic pattern the only association was with B57 (p < 0.007). There was no association between the LMP2 or LMP7 genotypes and any particular disease pattern.
Conclusions: These findings do not support an involvement of the HLA linked LMP2 and LMP7 gene polymorphisms in disease expression in psoriatic arthritis in addition to the known HLA class I and II associations.