Collagen-induced arthritis induced with bovine collagen type II purified from bovine cartilage of the knee. (a) Clinical signs of active arthritis, such as soft-tissue swelling and redness of affected joints, were scored twice a week using the semiquantitative scale Integrated Discomfort Score (see Table 2; red line). Number of affected joints (aj) involved in the arthritis is indicated above the dashed line. The monkeys were weighed twice a week, body weight serving as a surrogate disease marker. Body weight changes over time are expressed as the percentage of weight relative to day 0 (blue line). (b) A clear difference in swelling was observed between Mi119 (no swelling) and the prominent swelling in joints of Mi125. Structural changes could not, however, be visualized in corresponding radiograph of these joints. LH, left hand; RH, right hand. (c) Histology was performed on collagen-induce arthritis-affected proximal interphalangeal joints. Hyperplasia of the synovium was observed in joints that were clinically affected (Mi125). Signs of synovitis were also observed, however, in clinically nonaffected joints (Mi119; lymphocytic infiltrate).