p53 expression in rheumatoid and psoriatic arthritis synovial tissue and association with joint damage

Overexpression and functional mutations of p53 have been found in the synovial tissue (ST) of patients with rheumatoid arthritis (RA), but their clinical significance remains unclear.

To analyse p53 expression in the ST of patients with RA and psoriatic arthritis (PsA) and its association with joint damage.

Synovial biopsy specimens were obtained by arthroscopy in 45 patients (27 RA, 18 PsA). Radiographs of hands, feet, and the joint undergoing arthroscopy were obtained to evaluate the presence of erosive disease. Synovial cell populations were analysed using CD4, CD8, CD138, CD20, and CD68 monoclonal antibodies (mAbs). The p53 protein was determined by immunohistology using DO7 mAb in 34 patients (18 RA, 16 PsA). In 11 patients with early RA, the association between p53 and 1 year progression of radiographic damage was analysed using the Larsen-Scott method.

The p53 protein was detected in 16/18 (89%) patients with RA and in 9/16 (56%) patients with PsA, but its expression in RA was significantly higher than in PsA. In RA, p53 expression was significantly associated with erosive disease, and its scores were higher in patients with radiological progression. CD68 expression was also associated with erosions and radiological progression in RA. No association was found between either p53 or CD68 and erosive disease in PsA.

These results suggest that p53 ST overexpression and association with joint damage is characteristic of RA rather than PsA, and that p53 ST expression might be a prognostic marker of joint damage in RA.