Coexistence of rheumatoid arthritis in married couples: a search for etiological factors.

Epstein-Barr virus (EBV) and the genetic marker HLA-DR4 both appear to play a role in the etiology of rheumatoid arthritis (RA). Antibodies to viral capsid antigen and the early antigen complex of the EB virus as well as the HLA phenotype were studied in 6 families. Both spouses had classical or definite RA but none of their offspring, all adult, had any evidence of RA. At least 1 spouse of each couple had DR4 and this phenotype was found in 4 of the 8 offspring. All parents and their offspring had been infected with EBV. This study supports the association of DR4 and RA. The presence of DR4 in 4 normal adult offspring was not associated with the absence of primary infection or enhanced levels of EBV-specific antibodies.