High incidence of parvovirus B19 DNA in synovial tissue of patients with undifferentiated mono- and oligoarthritis

A common problem in rheumatological practice is inflammatory joint disease that cannot be classified. The prognosis of such undifferentiated arthritid es is uncertain. The synovial tissue of 41 consecutive patients with variou s forms of arthritis was tested for the presence of viral DNA in a diagnosi s-unaware fashion, using the polymerase chain reaction (PCR). Of all tested viruses, cytomegalovirus and parvovirus B19 were positive (each in 10 pati ents, two double-positives), whereas herpes simplex virus was positive in t wo patients. Rubella virus RNA was detected in three specimens. When the po sitivity for viral material was analysed in terms of distribution among the various diagnostic groups, it became evident that five out of 10 parvoviru s B19-positive patients belonged to the undifferentiated arthritis group, w hereas cytomegalovirus-positive patients were spread among all diagnostic g roups. This indicates the possibility of a new diagnostic category of undif ferentiated mono- and oligoarthritis, which can be identified by the presen ce of parvovirus B19 DNA in synovial tissue.