Objective: The contribution of polymorphism of transporter associated with antigen processing 1 and 2 (TAP1 and 2) alleles to the pathogenesis of Japanese SSc was studied.
Methods: TAP1 and TAP2 typing was carried out in 55 Japanese SSc patients and 95 normal Japanese subjects by the PCR-RFLP (restriction fragment length polymorphism) method. HLA-DR typing and HLA DRB1*15, *16 and *08 genotyping were carried out by the PCR and the PCR-SSCP (single-stranded DNA conformation polymorphism) methods, respectively.
Results: The frequencies of the TAP1A and TAP2A alleles were significantly increased in SSc with diffuse scleroderma (100%, p < 0.005; 80.0%, p < 0.001, respectively) and in SSc with antitopoisomerase 1 antibody (a-Scl-70), (93.2%, p = not significant (NS); 63.6%, p < 0.05). In contrast, the TAP1B allele was significantly decreased in diffuse scleroderma (0%, p < 0.005) and SSc with a-Scl-70 (4.5%, p < 0.05), and TAP2B was decreased in diffuse scleroderma (12.5%, p < 0.01).
Conclusion: Association analysis among TAP1A, TAP2A and DRB1*1502 indicated that increases in TAP1A and TAP2A were not primary, but were reflective of an increase in HLA DRB1*1502 in Japanese SSc patients with diffuse scleroderma and SSc with a-Scl-70.