EVALUATION OF ANTIBODY RESPONSE TO PNEUMOCOCCAL VACCINATION IN PATIENTS WITH INFLAMMATORY ARTHRITIS UNDER ANTI-TNF (ADALIMUMAB) TREATMENT

Abstract

Inflammatory arthritis increases the risk of pneumococcal infections. This study is aimed to investigate the immunoglobulin response to pneumococcal vaccine in patients with inflammatory arthritis receiving anti-TNF treatment. In this prospective observational study, a 0.5 ml 13-valent pneumococcal conjugate vaccine was injected to patients receiving 40 mg subcutaneous anti-TNF-alpha injection once every 15 days for inflammatory arthritis. Levels of anti-pneumococcal IgG were measured using the Enzyme-Linked ImmunoSorbent Assay (ZenTech) method in serum from patients pre- and 4 weeks post-vaccination. The study included 36 patients, 16 diagnosed with rheumatoid arthritis, 2 with psoriatic arthritis, and 18 with ankylosing spondylitis. Patients with rheumatoid arthritis had used corticosteroids during their follow-up. Patients that received pneumococcal vaccination were not included in the study. Anti-pneumococcal IgG titers in patients receiving anti-TNF treatment before pneumococcal vaccination varied: 4 patients had antibody titers below while 32 patientshad antibody titers above the protective levels (lower than 250 mU/ml according to kit instructions). Four weeks after the pneumococcal vaccine, the antibody titers of 4 patients, who had pre-vaccination levels below the protective threshold, increased above 250 mU/ml. Among the other 32 patients, the antibody titers doubled in 8 patients and tripled in 24 patients. While it is thought that the pneumococcal vaccine should preferably be injected before initiating the anti-TNF treatment in rheumatologic patients, we observed that sufficient protection was provided when it was done during the treatment, and we emphasized the significance of vaccination in these patients.