Induction of acute and chronic arthritis by intra-articular injection of preformed collagen-anticollagen complexes.

Three groups of rabbits were injected intra-articularly into the knee joints with preformed complexes of hydroxamated collagen and antiserum to denatured collagen respectively, with hydroxamated collagen and normal serum, hydroxamated collagen, anticollagen serum or saline as controls. From twelve rabbits, receiving only one injection and investigated 8 h later, only the joint tissues of rabbits which received immune complexes showed acute arthritis with severe infiltration of polymorphonuclears, leucocyte thrombi in vessels and haemorrhages. From six rabbits, receiving two consecutive injections (day 0 and day 2) and investigated 12 h after the last injection, only the joint tissue of rabbits which received immune complexes showed subacute-chronic arthritis. From sixteen rabbits receiving four consecutive injections day 0, day 2, day 7 and day 14) and investigated 7 days after the last injection, only the joint tissue of rabbits which received immune complexes showed severe chronic arthritis with infiltration of plasma cells, lymphocytes and nodule-like accumulation of lymphocytes whilst their joint fluid showed additionally a distinctly increased number of polymorphonuclears (3-15 x 10(6)) which differed with P less than 0-01 statistically from all controls.