AUTOANTIBODY PROFILE FOLLOWING INFLIXIMAB TREATMENT IN RHEUMATOID ARTHRITIS AND SPONDYLOARTHROPATHY

Background: Rheumatoid arthritis (RA) and spondyloarthropathy (SpA) patients are successfully treated with infliximab. There is indication that this therapy induces ANA and anti-dsDNA antibodies in RA.Objectives: To investigate the effect of infliximab on ANA, anti-dsDNA and anti-nucleosome antibodies in both RA and SpA and to investigate the effect of infliximab on rheumatoid factor (RF) and anti-citrullinated cyclic peptide antibodies (anti-CCP antibodies) in RA.Methods: Sera from 62 patients with refractory RA treated with infliximab (3 mg/kg infliximab IV at week 0,2,6 and every 8 weeks thereafter) were obtained at baseline and week 30. Sera from 35 patients with active SpA treated with infliximab (5mg/kg infliximab IV at week 0,2 and 6 and 10 mg/kg every 14 weeks thereafter) were obtained at baseline and week 34. All samples were tested for ANA (Indirect immunofluorecence [IIF] on HEp-2 cells), anti-dsDNA antibodies (IIF on Crithidia luciliae and Varelisa, PharmaciaDiagnostics), anti-nucleosome antibodies (Medizym anti-Nucleo, Medipan Diagnostica). The serumsamples of the 62 RA patients were also tested for RF Waaler-Rose (SERODIA-RA, Fujirebio Inc), RF Latex Fixation (DifcoLaboratories) and anti-CCP antibodies ELISA (Euro-Diagnostica) at week 0 and week 30. A p-value < 0.05 was considered to be statistically significant.Results: At baseline, 32/62 RA and 6/35 SpA patients were positive for ANA. After infliximab treatment, 51/62 RA and 31/35 SpA patients had a positive result for ANA. An increase in ANA-intensity of 2 or more steps (on a 0 to 5+ scale) was observed in 28/62 RA and in 26/35 SpA patients. A patient was defined as having anti-dsDNA antibodies when a positive result in both the IIF on Crithidia luciliae and anti-dsDNA ELISA was observed. According to this definition, none of the RA and SpA patients had anti-dsDNA antibodies at baseline. After treatment, 7/62 RA and 6/35 SpA patients developed anti-dsDNA antibodies. On the other hand, anti-nucleosome antibodies were observed in 1/62 RA and 3/35 SpA patients at baseline, whereas after treatment, 5/62 RA and 4/35 SpA patients were anti-nucleosome antibodies positive.At baseline, 41/62 RA patients were positive for RF Waaler-Rose, 39/62 RA patients were positive for RF Latex Fixation and 41/62 RA patients had a positive testresult for anti-CCP antibodies ELISA. After infliximab treatment, 33/62 RA patients were positive for RF Waaler-Rose, 31/62 RA patients were positive for RF Latex Fixation and we observed a positive test result for anti-CCP antibodies in the same 41 RA patients who were already positive at baseline. We also considered the data in a continous way: after infliximab, a significant decrease in titers was seen for RF Waaler-Rose and RF Latex Fixation. There was no difference in titers for anti-CCP antibodies.Conclusion: Infliximab treatment induced ANA and anti-dsDNA antibodies in both RA and SpA patients. In RA patients, infliximab treatment resulted in a decrease of RF Waaler-Rose and RF Latex Fixation, but no difference considering the anti-CCP antibodies was seen.Citation: , volume , supplement , year 2002, page Session: Humoral aspects of autoimmune disease