Antibodies to rheumatoid arthritis nuclear antigen (RANA) in Japanese patients with rheumatoid arthritis.

We studied antibodies to rheumatoid arthritis nuclear antigen (RANA) by the Ouchterlony method in 0.5% agarose plates, using soluble antigen extracted with 0.25 M sucrose solution from cultured Raji cells. Anti-RANA antibody was found in sera from 24 to 40 (60%) patients with rheumatoid arthritis (RA), from 4 of 20 (20%) patients with systemic lupus erythematosus (SLE), and from 2 of 30 (7%) healthy controls. When sucrose extracts from BJAB, Ramos, and JM cells were used as the cellular antigens, no anti-RANA precipitin lines were detected. Indirect immunofluorescence study, using Raji cells or human B lymphocytes transformed by EB virus as substrate tissues, demonstrated anti-RANA antibody as fine speckled nuclear staining. Although RA patients with positive anti-RANA antibody usually had high titers of anti-Epstein-Barr nuclear antigen (EBNA) and anti-viral capsid antigen (VCA) IgG antibodies, the Wilcoxon ranks sum test showed no close statistical correlation between the presence of anti-RANA antibodies and the titers of anti-EBNA or anti-VCA (IgG) antibodies. These data showed that the incidence of positivity of anti-RANA antibodies in Japanese RA patients is almost the same as that in American and European RA patients.