Background Multiple studies addressing the effects of biologics on the synovial tissue in rheumatoid arthritis (RA) patients have been reported. There are, however, few studies comparing histopathological changes in the synovial tissue in the same RA patients between before and after biologics treatment.
Objectives We examined biologics impacts on RA synovial tissues based on pathological findings in them collected during surgeries for the same patient before and after biological drug usage.
Methods Synovial tissues were collected from 22 RA joints before and after biologics. The average age and disease duration of the study subjects were 63.3 and 21.8, respectively. Histopathological changes in the synovial tissues were compared based on Rooney's score, and presence or absence of fibrinoid degeneration and plasma cell infiltration in the subsynovial tissue. We examined correlation between pathological findings in RA synovium and disease activity under biologics. Disease activity was assessed by CDAI. Etanercept, Infliximab, Tocilizumab, Adalimumab and Abatacept was used as biological drug for 11, 5, 2, 2 and 2 joints respectively.
Results Rooney score between before and after biological drug usage improved from 30.6 to 12.6 showing significant difference. Significant improvement in Rooney score was observed in all items. Fibrinoid degeneration was observed in 18 cases (81.8%) and 4 cases (18.2%) before and after biologics treatment, respectively, demonstrating a significant reduction with biologics treatment. After biologics treatment, Rooney's scores in the remission and low disease activity, and moderate disease activity were 7.1 and 15.9, respectively, showing a statistically significant difference. In addition, the moderate disease activity had significantly higher scores in perivascular lymphocytic infiltration, lymphoid follicle and lymphocyte infiltration compared to the remission and low disease activity. Plasma cells after biologics treatment were observed at 0%, 22.2% and 63.3% in the remission, low disease activity and moderate disease activity respectively, indicating the greater disease activities were associated with the more plasma cells in the subsynovial tissue.
Conclusions The study results demonstrated that biologics treatment significantly ameliorated inflammatory changes in the synovial lining cells and subsynovial tissue. In addition, the results suggested that histopathological findings in the subsynovial tissue reflected disease activity.
Disclosure of Interest None declared