Immunoglobulins IgG and IgM in synovial fluids of swine with erysipelothrix polyarthritis

Concentrations of IgG and IgM immunoglobulins in synovial fluids and sera from a group of swine with experimentally produced Erysipelothrix rhusiopathiae polyarthritis were measured to determine if there was local synthesis of these immunoglobulins by plasma cells in arthritic synovial tissue. IgG and, to a lesser extent, IgM were significantly higher in arthritic than in nirmal synovial fluids from the same group of swine and this increase could only partly be explained by the increased permeability of the arthritic synovial membrane to plasma proteins. When synovial fluid values of IgG and IgM were calculated on the basis of companion serum concentration it was found that 82% of IgG, and 25% of IgM estimations were significantly elevated above levels in normal joints indicating that IgG was the dominant immunoglobulin synthesized.