VARIABILITY IN CYTOKINE AND CELL-ADHESION MOLECULE STAINING IN ARTHROSCOPIC SYNOVIAL BIOPSIES - QUANTIFICATION USING COLOR VIDEO IMAGE-ANALYSIS

Objective. To investigate the variability in immunostaining for cytoki nes and cell adhesion molecules using multiple arthroscopically direct ed synovial biopsies from within a rheumatoid knee joint, quantitated by color video image analysis. Methods. Needle arthroscopic biopsies w ere taken from multiple sites (4-7 sites) around a knee joint in 8 pat ients with rheumatoid arthritis (RA). In 5 patients, immunoperoxidase staining for the cytokines tumor necrosis factor alpha (TNF-a), interl eukin 8 (IL-8), and IL-1B as well as the IL-1 receptor antagonist prot ein (IL-1ra) was performed. In 3 patients, immunoperoxidase staining f or the cell adhesion molecules' E-selectin (CD62E), P-selectin (CD62P) , intercellular adhesion molecule 1 (ICAM-1, CD54), and platelet endot helial cell adhesion molecule (PECAM, CD31) was performed. Immunostain ing was quantified using color video image analysis. Results. The over all probability of paired biopsies from the same RA knee joint being s ignificantly different from each other due to sampling variation was a t most 22% for cytokine staining (usually less than 10%). There were n o significant differences between intrabiopsy and interbiopsy variabil ity for cell adhesion molecule staining of the sublining and vessels. Conclusion. The variability in cytokine and cell adhesion molecule sta ining within any single biopsy usually reflects the variability betwee n biopsies taken from different sites in the same rheumatoid joint whe n the immunostaining is quantified using color video image analysis. T herefore, only a small number of synovial biopsies are required to acc urately determine the cytokine and cell adhesion molecule expression i n a single joint.