Histopathological observation of joint lesions of extremities in mice transferred genome

Pathological examination of arthritic lesions in transgenic mice produced by the pX region of the human T-cell leukemia virus type-1 (HTLV-1) was carried out. Clinically, erythema, swelling and/or ataxia of the limb joints were observed in many transgenic mice about 1 month-old. Histopathologically, proliferation of synovial lining cells, infiltration of inflammatory cells with lymphoid structures and formation of pannus with cartilage and/or subchondral bone destructions were observed in various joints of transgenic mice. The frequency of abnormalities in the joints was higher in females than in males. These histopathological findings were very similar to those of human rheumatoid arthritis (RA). Present results indicate that the pX genome of the HTLV-1 is an etiological agent for the incidence of arthritic lesions in the transgenic mice.