LETTER Rheumatoid arthritis after

infection Polyarthropathy associated with human par-vovirus B19 (B19) is usually transient, but often resembles rheumatoid arthritis (RA).1–3 However, B19 DNA screened by polymerase chain reaction (PCR) may be positive not only in autoimmune diseases, but also in non-arthropathy.4 To study whether or not RA occurs after acute B19 infection, we con-ducted a prospective study of patients with acute onset polyarthritis. Sixty seven cases showing acute inflammatory polyarthritis from January 1990 to June 1990 were exam-ined and followed up for six years. Among them, 12 (9 female and 3 male) exhibite