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Inflamm Bowel Dis. 2016 Jul;22(7):1655-61. doi: 10.1097/MIB.0000000000000797.

Anti-infliximab Antibodies with Neutralizing Capacity in Patients with Inflammatory Bowel Disease: Distinct Clinical Implications Revealed by a Novel Assay.

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*Gastroenterology Department, Rambam Health Care Campus, Haifa, Israel; †Bruce Rappaport School of Medicine, Technion-Israel Institute of Technology, Haifa, Israel; ‡Gastroenterology department, Sheba Medical Center Tel Hashomer, Ramat Gan, Israel; and §Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.



About 60% of infliximab (IFX)-treated patients develop antidrug antibodies (ADA), although their clinical significance remains disputed. The aim of this study was to develop an assay for assessing ADA-neutralizing potential, and clinical significance.


An immune assay was devised in which the inhibition of IFX binding to plated-tumor necrosis factor in the presence of patient sera or controls, was assessed and defined as IFX-tumor necrosis factor binding reduction ratio (ITBR). The assay was compared to a bioassay in which tumor necrosis factor-α-induced interleukin-8 secretion from HT-29 cells was assessed after addition of IFX to ADA-containing sera or control sera.


Both assays detected neutralizing antibodies in 39 of 44 ADA-positive sera. The median ITBR was 3.66 (mean 4.9 ± 3.2) in 29 ADA-positive patients with loss of response (LOR), and 1.3 (mean 1.9 ± 1.3) in 15 patients without LOR (P = 0.001). ADA titers in both groups were similar (median 9.5 and 10.2 μg/mL, respectively P = 0.74). Using an ITBR of 1.65, the sensitivity for LOR detection was 86.2% and the specificity was 66.7%. (positive predictive value 83%; negative predictive value 71.4%; P = 0.001). When early ADA-IFX-sera from IFX-treated patients with or without subsequent LOR were compared, the median ITBRs were 1.1 and 0.57, respectively (P = 0.028).


Detection of neutralizing antibody activity was superior to antibody quantization by enzyme-linked immunosorbent assay with respect to correlation with clinical LOR, and for prediction of subsequent LOR. These findings may assist in optimizing infliximab therapy in patients with inflammatory bowel disease.

[Indexed for MEDLINE]

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