Antibodies to Epstein-Barr virus associated antigens in Pima Indians with and without rheumatoid arthritis

We investigated anti-rheumatoid arthritis-associated nuclear antigens (RANA) and other anti-Epstein-Barr virus (EBV) antibodies in a uniquely controlled study in female Pima Indians of Arizona, an RA prone population. Four groups of age and sex-matched individuals were formulated: (1) individuals positive for rheumatoid factor (RF) who had clinical evidence of rheumatoid arthritis (RA); (2) individuals seropositive for RF, but without arthritis; (3) individuals seronegative for RF, but with various kinds of arthritis; (4) those seronegative without arthritis. The mean anti-RANA in the seropositive RA group was significantly above those of the other groups but the anti-VCA and anti-EBNA titers did not differ. The anti-RANA was shown to be independent of RF. Comparing the Pima Indians to Caucasians in La Jolla, we found the mean anti-RANA titers of the Pimas to be significantly higher than those of the Caucasians. This study thus establishes clearly that elevated anti-RANA titers are characteristics of this American Indian group, just as they are of Caucasian groups. The elevated anti-RANA titers in RA patients may represent a unique hyperresponsiveness to this antigen, since there is no consistency in the reported levels of antibodies to other EBV-related antigens.