GusB, Hyal1 and klotho gene expression in arthritis patients' synovial membrane and fibroblast samples. Gene expression for β-D-glucuronidase (GusB), hyaluronidase 1 (Hyal1), and klotho genes was lower in rheumatoid arthritis (RA) and osteoarthritis (OA) synovial fibroblasts (SFs) than in RA and OA synovial membrane (SM) tissue samples (Mann-Whitney rank sum test). The Hyal1 gene expression was significantly higher in OA SM as compared with RA SM (Mann – Whitney rank sum test). The sperm adhesion molecule 1 gene expression was undetectable. Gex, gene expression; HGPRT, hypoxanthine phosphoribosyl transferase. *P < 0.05; **P < 0.01; ***P < 0.001.