Double-filtration plasmapheresis with a plasma fractionator pore size of 20 nm should selectively remove large molecular weight substances like rheumatoid factor and IgM. This was proposed to be more likely to be helpful for rheumatoid arthritis than standard plasma exchange.
To evaluate the efficacy of double-filtration plasmapheresis (DFPP) in the treatment of patients with active rheumatoid arthritis.
Eighty-two patients were randomly assigned, 42 to the DFPP group and 40 to the no-DFPP group. All patients received sulfasalazine (0.75 g 3 times daily) plus methotrexate (10 mg orally once weekly). All patients had been on stable doses for more than 3 months. DFPP was performed once a week for 2 to 3 sessions. A total of 121 plasmapheresis procedures were performed in 42 patients. Control patients did not receive sham DFPP. The efficacy measures recorded 1 day after the final treatment and every month in follow-up for 4 to 22 months included the American College of Rheumatology (ACR) 20%, 50%, and 70% improvement criteria (ACR20, ACR50, and ACR70), the Health Assessment Questionnaire estimate of disability and the disease activity index.
Patients in the DFPP group had ACR20, ACR 50, and ACR70 improvements immediately after the last treatment of 100%, 92.9%, and 81.0%, when compared with the patients in no-DFPP group 17.5%, 0%, and 0% (P < 0.001). Significant change from baseline was observed in Health Assessment Questionnaire scores in the DFPP group, but not in the no-DFPP group (P < 0.001). The changes from baseline in the disease activity scores were significantly greater than in the no-DFPP group (P < 0.001). Improvements were maintained during follow-up of 7 to 22 months.
This open trial showed that DFPP therapy significantly altered the signs and symptoms of active rheumatoid arthritis. There were increases in physical function and improvement in quality of life. This is proposed as an approach that merits further investigation.