[Immunopathology and pathogenesis of chronic erysipelas polyarthritis of swine]

Several immuno-pathological aspects of polyarthritis following experimental infection with erysipelas in pigs were studied for two years. Aseptic and specifically pathogenfree animals were infected subcutaneously and intravenously-intraarticularly with living erysipeals bacteria (erysipelothrix rhusiopathiae) of serotype B. After an initial febrile phase a progressive polyarthritis and disco-spondylitis developed. Some animals also developed thrombo-endocarditis. Hypergammaglobulinemia and high titers of specific antibodies were observed during the whole experimental period. Antiglobulin factors, however, were not detected in the serum or the synovium. In some animals collagen antibodies were demonstrated in synovial tissue. Bacterial examination of the synovium showed that erysipelas bacteria were present in arthritic joints for months. Living erysipelas bacteria were isolated 24 months after the experimental infection from synovial tissue of two pigs. The polyarthritis was characterised by exudates rich in fibrin, villous proliferation, pannus formation, cartilage erosions, and peri-articular fibrosis. IgG and specific erysipelas antibodies were demonstrated in plasma cells from synovial tissue by immuno-histological methods. The findings emphasize the morphological resemblance of the erysipelas induced chronic polyarthritis in pigs to human rheumatoid arthritis.