BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.
BACKGROUND: 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. METHODS: An immune assay was devised in which the inhibition of IFX binding to plated-tumornecrosis 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 tumornecrosis factor-α-induced interleukin-8 secretion from HT-29 cells was assessed after addition of IFX to ADA-containing sera or control sera. RESULTS: 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). CONCLUSIONS: 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.
Authors: Mohsin El Amrani; Camiel Göbel; Annelies C Egas; Stefan Nierkens; C Erik Hack; Alwin D R Huitema; Erik M van Maarseveen Journal: J Transl Autoimmun Date: 2019-05-28
Authors: Renáta Bor; Klaudia Farkas; Anna Fábián; Anita Bálint; Ágnes Milassin; Mariann Rutka; Mária Matuz; Ferenc Nagy; Zoltán Szepes; Tamás Molnár Journal: PLoS One Date: 2017-03-31 Impact factor: 3.240