Effects of Hyaluronidase on Sheep Cell Agglutination and Latex Fixation Tests in Contemporary Sera and Joint Fluids †

Most clinical studies involving rheumatoid factors are made on sera; relatively few investigations are reported on rheumatoid factors in joint fluid, connective tissue extracts, interstitial fluid and cells. Joint fluid of patients with rheumatoid arthritis often contains rheumatoid factor, measured by the latex fixation and sheep cell agglutination tests.,"'8 Mellors, et al.' established evidence that in patients with rheumatoid arthritis, rheumatoid factor is synthesized by plasma cells in at least three tissues, lymph nodes, rheumatoid nodules and synovialis. Since plasma cells do not circulate, the rheumatoid factor molecule probably appears first in connective tissues and moves to serum, presumably via the lymphatic system. Krehl, et al.' reported results of sheep cell agglutination tests on simultaneously collected sera and joint fluids from patients with rheumatoid arthritis and certain other diseases. Joint fluid tests were less often positive than serum tests, but when joint fluid was positive, it was so in higher titer than serum. Joint fluids were examined before and after incubation with hyaluronidase. Fluids showing positive tests before hyaluronidase treatment did not change after incubation. However, significant numbers of tests previously negative became positive after hyaluronidase treatment. Except for its hyaluronic acid content joint fluid is regarded as having the chemical composition of an ultrafiltrate of plasma; since hyaluronidase specifically hydrolyzes hyaluronic acid, and the sheep cell agglutination tests in joint fluid, previously negative, disclosed positive tests after hyaluronidase treatment, Krehl, et al.' interpreted the change to positivity as being due to some change in hyaluronic acid or a consequence of such change. One possibility is that a protein in complex with hyaluronic acid