ELEVATED NERVE GROWTH-FACTOR LEVELS IN THE SYNOVIAL-FLUID OF PATIENTSWITH INFLAMMATORY JOINT DISEASE

A novel pH shock extraction procedure was used to measure nerve growth factor (NGF) levels in both normal and inflamed synovial fluids using a sensitive and specific two-site enzyme linked immunosorbant assay. To date no data is available on NGF levels in normal synovial fluids. Synovial fluids were taken from 5 normal volunteers, 12 patients with rheumatoid arthritis and 10 patients with other inflammatory arthropat hies. The mean +/- SEM NGF concentration in normal synovial fluids was 95 +/- 33.2 pg/ml (range 39.1-143.1 pg/ml), whereas the mean NGF conc entration in the synovial fluids taken from patients with rheumatoid a rthritis was 532.5 +/- 123.8 pg/ml (range 152-1686 pg/ml). The mean NG F concentration in patients with other inflammatory arthropathies was also raised(430.6 +/- 90 pg/ml; range 89-1071 pg/ml). The NGF concentr ations were significantly higher in the synovial fluids from both infl amed groups (ANOVA p < 0.05) compared to normals. Raised levels of NGF in synovial fluid may contribute directly to joint inflammation via a ctivation of inflammatory cells.