Objective: To elucidate the roles of HLA genes in the clinical presentation of patients with connective tissue disease and serum anti-U1 small nuclear RNP antibody.
Methods: HLA class I antigens and HLA class II alleles were determined in 43 Japanese patients with anti-U1 RNP antibody alone, by microcytotoxicity testing and DNA typing, respectively. Prospectively recorded clinical and laboratory features were analyzed in relation to HLA class I and class II types.
Results: DQB1*0303 was associated with lupus-related symptoms including fever, malar rash, oral ulcers, hypocomplementemia, and high-titer anti-double-stranded DNA antibody. Other HLA-clinical associations included DR2 with pleuritis, DR4 with hand swelling, and DRB1*0405 with arthritis.
Conclusion: These HLA-clinical associations explain, in part, the heterogeneous clinical presentation in patients with anti-U1 RNP antibody.