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Arthritis
Volume 2015 (2015), Article ID 784825, 7 pages
http://dx.doi.org/10.1155/2015/784825
Research Article

Antibodies to Infliximab and Adalimumab in Patients with Rheumatoid Arthritis in Clinical Remission: A Cross-Sectional Study

1Department of Clinical Biochemistry, Copenhagen University Hospital at Køge, 4600 Køge, Denmark
2Department of Rheumatology, Copenhagen University Hospital at Køge, 4600 Køge, Denmark
3The Parker Institute, Department of Rheumatology, Copenhagen University Hospitals at Frederiksberg and Bispebjerg, 2000 Copenhagen F, Denmark
4Institute for Inflammation Research (IIR), Rigshospitalet University Hospital, 2100 Copenhagen, Denmark
5DANBIO registry, Copenhagen Center for Arthritis Research, Center for Rheumatology and Spine Diseases, Copenhagen University Hospital Glostrup, 2600 Glostrup, Denmark
6Department of Rheumatology, Copenhagen University Hospital Glostrup, 2600 Glostrup, Denmark
7Department of Rheumatology, Odense University Hospital, 5000 Odense, Denmark
8Department of Rheumatology, Copenhagen University Hospitals at Frederiksberg and Bispebjerg, 2000 Frederiksberg, Denmark
9Department of Rheumatology, Copenhagen University Hospital at Gentofte, 2900 Gentofte, Denmark
10Department of Rheumatology, Copenhagen University Hospital at Holbæk, 4300 Holbæk, Denmark

Received 22 December 2014; Accepted 30 January 2015

Academic Editor: Alejandro Balsa

Copyright © 2015 Grith P. Eng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective. To investigate if antibodies towards biological TNF-α inhibitors (anti-TNFi Abs) are present in patients with rheumatoid arthritis (RA) in clinical remission and to relate any anti-TNFi Abs to circulating level of TNF-α inhibitor (TNFi). Methods. Patients with RA, treated with infliximab or adalimumab, and in clinical remission (DAS28(CRP) < 2.6) were included from 6 out-patient clinics. In blood samples, presence of anti-TNFi Abs was determined by radioimmunoassay, and concentration of bioactive TNFi was measured by a cell-based reporter gene assay. Results. Anti-TNFi Abs were present in 8/44 patients (18%) treated with infliximab and 1/49 patients (2%) treated with adalimumab (). In the former group, anti-TNFi Abs corresponded with low levels of TNFi (). Anti-TNFi Ab-positive patients had shorter disease duration at initiation of TNFi therapy () but were similar for the rest of the compared parameters. Conclusions. In RA patients in clinical remission, anti-TNFi Abs occur frequently in patients treated with infliximab, while they occur rarely in patients treated with adalimumab. Presence of anti-infliximab Abs is accompanied by low or undetectable levels of infliximab. These data suggest that continued infliximab treatment may be redundant in a proportion of RA patients treated with infliximab and in clinical remission.