Identification of the receptor for advanced glycation end products in synovial tissue of patients with rheumatoid arthritis

Objectives: Generation of advanced glycation end products ( AGE) is an inevitable process in vivo and can be accelerated under pathologic conditions such as oxidative stress, e. g. in rheumatoid arthritis ( RA). This process is mediated by the AGE-specific receptor ( RAGE). In this study we analysed the presence of RAGE in RA and osteoarthritic (OA) synovial tissue using immunohistology. Methods: Frozen synovial tissue samples from 11 RA patients and 12 OA patients were treated with goat anti-RAGE immunoglobulin G (IgG) and rabbit antigoat IgG. Immunostaining was visualised with streptavidin horse radish peroxidase ( chromogen amino-ethyl-carbazole). Cell differentiation was performed with antibodies against CD68, CD45RO, and CD20. Results: In 9/11 RA and 8/12 OA synovial specimens, RAGE was detected in synovial lining, sublining, and stroma. In RA, many T cells ( CD45RO(+)) and some macrophages ( CD68(+)) showed positive immunostaining for RAGE, whereas B cells were mostly negative. We found no difference in staining patterns between the RA and OA samples. Conclusions: We detected RAGE in RA and OA synovial tissue. The presence of RAGE on macrophages, T cells, and some B cells suggests its role in the pathogenesis of inflammatory joint disease.