Objective: To investigate the effect of total removal of the hyaline articular cartilage on dendritic cells in synovial membrane in rheumatoid arthritis (RA) or ankylosing spondylitis (AS).
Patients and methods: Immunohistochemical staining for two dendritic cell markers, CD35 and RFD1, was carried out on synovial membrane specimens from arthritis patients undergoing primary (n=10) or revision (n=8) total hip replacement (THR). The results are expressed as the number (mean+/-standard deviation) of positive cells per 1000 total cells.
Results: CD35-(112+/-9) and RFD1-(27+/-5) positive cells were found in all primary RA synovial membrane, while only two out of eight synovial membrane samples from revision THR contained CD35-positive follicular dendritic cells (nine and 12 cells), and no revision samples contained any RFD1-positive interdigitating dendritic cells.
Conclusion: Removal of the hyaline articular cartilage reduces the infiltration and functional differentiation of dendritic cells in synovial membrane. Our findings suggest that the antigen driving chronic arthritis/synovitis is contained in the hyaline articular cartilage.