Clinical correlations of infliximab trough levels and antibodies to infliximab in South Korean patients with Crohn’s disease

Figure 1 Scatter diagram of the study patients. Of these 138 subjects, 84 (60.9%) had quiescent disease and 54 (39.1%) had active disease. The overall median infliximab trough level (IFX-TL) value was 0.941 μg/mL. In total, 91 patients were antibodies to infliximab (ATI) negative (65.9%) and 47 patients were ATI positive (34.1%), with an overall median ATI value of 8.846 (IQR 7.719-16.727) AU/mL.

Figure 2 Comparisons of the infliximab trough levels and antibody to infliximab levels between patients with quiescent or active disease. The median infliximab trough levels (IFX-TLs) were 1.423 μg/mL (IQR 0.877-2.483) and 0.163 μg/mL (IQR 0.002-0.636), respectively (P < 0.001) (A) and the median antibodies to infliximab (ATIs) levels were 8.064 AU/mL (IQR 6.929-9.908) and 11.209 AU/mL (IQR 8.008-118.835), respectively (P < 0.001) (B) in patients with quiescent and active disease.

Figure 3 Comparison of the infliximab trough levels between patients with/without antibody to infliximab. In the ATI-negative and -positive groups, the median infliximab trough levels (IFX-TLs) were 1.415 μg/mL (IQR 0.570-2.495) and 0.141 μg/mL (IQR 0.002-0.869), respectively (P < 0.001). ATI: Antibodies to infliximab.

Figure 4 Comparisons of infliximab trough levels and antibody to infliximab levels in patients with/without immunomodulators. There were no differences in the median infliximab trough level (IFX-TL) (0.632 μg/mL and 1.150 μg/mL, respectively; P = 0.274) (A) and median antibodies to infliximab (ATIs) (8.655 AU/mL and 9.017 AU/mL, respectively; P = 0.083) (B) levels between the 2 groups according to the use of concomitant immunomodulators.