[Study of lysosomal enzymes in human synovial membrane and fluid from rheumatoid and non-rheumatoid patients].

In rheumatoid arthritis, it is well known that lysosomal enzymes such as lysozyme and acid phosphatase have a function of destroying bone and synovial tissue of joints. In order to analyze the localization and the difference of distribution of lysozyme and acid phosphatase on the synovial tissue of rheumatoid arthritis (RA) and non-RA joints, immunohistochemical and histochemical methods were employed. Lysozyme was detected with formalin-fixed, paraffin-embedded materials in 82 cases of synovial tissue (RA 50 cases, non-RA 32 cases) using the unlabelled peroxidase anti-peroxidase (PAP) method following Taylor, et al. Acid phosphatase was detected with the naphthol AS method using frozen sections. In addition, in some cases of RA, alpha 1-antitrypsin and alpha 1-antichymotrypsin were also examined in synovium by the PAP method. For quantitative analysis of lysozyme in synovial fluid, lyso-plate were used on 98 cases (RA 58 cases, non-RA 40 cases). Further, acid phosphatase was quantitated with phenyl phosphoric acid. The results show, histologically, that lysozyme was more predominantly and more specifically located in the synovial cells, especially in the synovial lining cells of RA joints than non-RA joints. Lysozyme was distributed in the cytoplasm of synovial cells in a fine granular or small globoid pattern. On the other hand, no lysozyme was detected on the infiltrated lymphocytes and plasma cells. Infiltration of leukocytes was relatively slight. Acid phosphatase was intensively located in the same portion of RA synovium as that of lysozyme. Electron microscopically, synovial surface cells showed an increase in number, and they contained dominant, well-developed, rough endoplasmic reticulum and electron dense bodies. Fibrillar matrix were present in the cytoplasm and in the extracellular space in an amorphous pattern. Enzyme activity of lysozyme in 58 RA synovial fluid was 113 +/- 101 (mean +/- standard deviation) micrograms/ml and that in 40 non-RA (11 osteoarthritis, 20 autopsy cases, and others) was 35 +/- 31 micrograms/ml. Acid phosphatase activity of 47 RA was 11.97 +/- 10.45 I.U. (International Unit) and that of 38 non-RA was 5.16 +/- 3.77 I.U. A significant difference of lysosomal enzyme activity was thus found in the synovial fluid between RA and non-RA. Clinical laboratory data, namely, ESR (erythrocyte sedimentation rate) and CRP (C-reactive protein) as an activity of rheumatic disease were evaluated. Correlation rate between ESR and lysozyme in RA synovial fluid was 0.279 (the value of P less than 0.05) and between ESR and acid phosphatase was 0.259 (P less than 0.05). Thus no significant correlation was found among them.(ABSTRACT TRUNCATED AT 400 WORDS)