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Around a 20–30% of inflammatory bowel disease (IBD) patients are diagnosed before they are 18 years old. Anti-TNF drugs can induce and maintain remission in IBD, however, up to 30% of patients do not respond. The aim of the work was to identify markers that would predict an early response to anti-TNF drugs in pediatric patients with IBD. The study population included 43 patients aged <18 years with IBD who started treatment with infliximab or adalimumab. Patients were classified into primary responders (n = 27) and non-responders to anti-TNF therapy (n = 6). Response to treatment could not be analyzed in 10 patients. Response was defined as a decrease in over 15 points in the disease activity indexes from week 0 to week 10 of infliximab treatment or from week 0 to week 26 of adalimumab treatment. The expression profiles of nine genes in total RNA isolated from the whole-blood of pediatric IBD patients taken before biologic administration and after 2 weeks were analyzed using qPCR and the 2−∆∆Ct method. Before initiation and after 2 weeks of treatment the expression of SMAD7 was decreased in patients who were considered as non-responders (p value < 0.05). Changes in expression were also observed for TLR2 at T0 and T2, although that did not reach the level of statistical significance. In addition, the expression of DEFA5 decreased 1.75-fold during the first 2 weeks of anti-TNF treatment in responders, whereas no changes were observed in non-responders. Expression of the SMAD7 gene is a pharmacogenomic biomarker of early response to anti-TNF agents in pediatric IBD. TLR2 and DEFA5 need to be validated in larger studies.

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Background Therapeutic drug monitoring (TDM) of adalimumab (ADA) in inflammatory bowel diseases (IBDs) has gained increased attention since several studies showed a correlation between drug levels and mucosal healing. The limitations of routine usage of enzyme-linked immunoabsorbent assay (ELISA) kits for measuring serum ADA concentrations have prompted the development of rapid methods, such as Quantum Blue (QB). We evaluated the interchangeability and agreement between the QB method and two established ELISA kits, Promonitor (PM) and Lisa-Tracker (LT). Methods Fifty samples from patients with IBD were included. Quantitative analysis was performed using the ANOVA test for repeated measures, Deming regression and the Bland-Altman plot. Clinical implications were evaluated by concordance in classifying patients into therapeutic windows according to the proposed cut-off levels for subtherapeutic (either <5 or <7.5 μg/mL) and supratherapeutic (>12 μg/mL) ranges. Results Statistical differences were detected between the QB method and the two ELISA kits, with QB overestimating ADA serum values compared to them. A lack of interchangeability was observed between methods, with greater differences as ADA levels increased. An analysis of a sub-set of samples with ADA values below 9 μg/mL (n = 25) showed that QB fulfilled the criteria to be interchangeable with the LT assay. Concordance for patient classification into ADA therapeutic windows was better for QB vs. LT than for QB vs. PM, with high agreement (>75%) for subtherapeutic levels among the three methods. Conclusions Although quantitative differences existed between the rapid method and ELISA kits that hampered their interchangeability, the agreement for identifying patients with subtherapeutic values of ADA was high.