INTRODUCTION
Tumor necrosis factor alpha (TNF alpha) blockers such as infliximab
(IFX) and adalimumab (ADA) had significantly changed the course of
inflammatory diseases such as rheumatoid arthritis (RA),
spondyloarthritis (SpA) and Crohn’s disease (CD). However, about 30% of
patients do not respond to these treatments [1]. This lack of
response may be due to an immediate non-response known as primary
failure, or to a loss of response after an initial good response called
secondary failure. In the case of secondary failure, immunogenicity has
been incriminated [2]. It is defined by the development of antidrug
antibodies (ADAbs) [2].
The presence of ADAbs can decrease serum drug levels by neutralizing the
functional part of the biologic or by forming immune complexes between
the biologic and the ADAbs, increasing thereby the clearance of the drug
[3-5]. Many studies have been performed in order to evaluate the
impact of immunogenicity on the clinical response [5]. The aim of
this study was to determine the prevalence anti ADAbs against IFX and
ADA, and the trough serum concentration of IFX and ADA in RA, SpA or CD
patients and to assess their impact on the therapeutic response.