Infiltrations of plasma cells in synovium predict inadequate response to Adalimumab in Rheumatoid Arthritis patients

Rheumatoid arthritis (RA) is a clinically heterogeneous and complex autoimmune disease, making the prediction of therapeutic responses a significant challenge. This study aims to assess the role of clinical and synovial biomarkers in predicting poor response to adalimumab treatment in RA patients.

This single-center prospective study included 56 RA patients who had an inadequate response to methotrexate (MTX). At baseline, comprehensive assessments including complete blood count, liver and kidney function tests, blood glucose levels, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), anti-citrullinated protein antibody (ACPA), as well as counts of swollen and tender joints, Health Assessment Questionnaire (HAQ) score, pain visual analogue scale (VAS) scores, and DAS28-CRP scores were conducted. Synovial biopsies were performed, followed by an efficacy evaluation at 12 weeks of adalimumab treatment. Patients not meeting the ACR20 criteria were classified into the non-responder group, with the remainder categorized as the responder group.

Out of the participants, 24 (42.9%) failed to achieve ACR20 with adalimumab treatment. Non-responders exhibited higher infiltration of plasma cells in the synovium. Multivariate logistic regression analysis identified the presence of plasma cells as an independent risk factor for inadequate response to adalimumab.

Inadequate responses to adalimumab in RA patients were associated with increased plasma cell infiltrations in the synovium. These findings suggest a promising target for tailored therapies in rheumatoid arthritis.