Title: A new autoantibody in patients with rheumatoid arthritis
Abstract: In this study, a new autoantibody was identified in patients with rheumatoid arthritis (RA), which was tentatively named as anti-HaT-1 antibody.It was shown by double immunodiffusion method that anti-HaT-1 antibody had independent specificity from the hitherto reported autoantibodies in sera of patients with connective tissue diseases.The antigenicity of the HaT-1 antigen was destroyed with treatment by trypsin, whereas it was not inactivated by digestions with either DNase or RNase.The HaT-1 antigen was considered to be an acidic protein with approximate molecular weight of 150, 000 daltons. The HaT-1 antigen was present in soluble extracts of human and rat livers but not detected in those of rabbit and calf thymus or Raji cell. The HaT-1 antibody was detected in sera of 9 out of 45 RA patients, 2 out of 16 RA patients with Sjogren's syndrome. And RA patients with anti-HaT-1 antibody had higher incidence of digital angitis (nailfold thrombosis) and subcutaneous nodule than those without this antibody (p<0.01).It was suggested that anti-HaT-1 antibody is a new antibody which was specific to RA.