ADA and allergic reaction
In our study, the occurrence of allergic reactions was significantly correlated with the presence of ADAbs and with a lower residual level. Our data agree with several studies which have found that the presence of ADAbs is a risk factor for allergic reactions [24,25]. A meta-analysis with systematic review of the literature including 1185 IBD cases found that patients with anti-IFX ADAbs were 2 times more likely to develop acute infusion reactions and 6 times more likely to develop severe reactions [38]. Vande Casteele et al. demonstrated that a low residual IFX level <2.2 μg/ml was associated with the presence of allergic reactions in CD [39].