The genetic polymorphisms rs2395185 and rs2097432 in HLA genes have been associated with the response to anti-TNF treatment in inflammatory bowel disease (IBD). The aim was to analyze the association between these variants and the long-term response to anti-TNF drugs in pediatric IBD. We performed an observational, multicenter, ambispective study in which we selected 340 IBD patients under 18 years of age diagnosed with IBD and treated with anti-TNF drugs from a network of Spanish hospitals. Genotypes and failure of anti-TNF drugs were analyzed using Kaplan-Meier curves and Cox logistic regression. The homozygous G allele of rs2395185 and the C allele of rs2097432 were associated with impaired long-term response to anti-TNF drugs in children with IBD after 3 and 9 years of follow-up. Being a carrier of both polymorphisms increased the risk of anti-TNF failure. The SNP rs2395185 but not rs2097432 was associated with response to infliximab in adults with CD treated with infliximab but not in children after 3 or 9 years of follow-up. Conclusions: SNPs rs2395185 and rs2097432 were associated with a long-term response to anti-TNFs in IBD in Spanish children. Differences between adults and children were observed in patients diagnosed with CD and treated with infliximab.

Changes in gene expression profiles among individuals with inflammatory bowel diseases (IBDs) could potentially influence the responsiveness to anti-TNF treatment. The aim of this study was to identify genes that could serve as predictors of early response to anti-TNF therapies in pediatric IBD patients prior to the initiation of treatment. We conducted a prospective, longitudinal, and multicenter study, enrolling 24 pediatric IBD patients aged less than 18 years who were initiating treatment with either infliximab or adalimumab. RNA-seq from blood samples was analyzed using the DESeq2 library by comparing responders and non-responders to anti-TNF drugs. Bioinformatic analyses unveiled 102 differentially expressed genes, with 99 genes exhibiting higher expression in responders compared to non-responders prior to the initiation of anti-TNF therapy. Functional enrichment analyses highlighted defense response to Gram-negative bacteria (FDR = 2.3 ×10-7) as the most significant biological processes, and hemoglobin binding (FDR = 0.002), as the most significant molecular function. Gene Set Enrichment Analysis (GSEA) revealed notable enrichment in transcriptional misregulation in cancer (FDR = 0.016). Notably, 13 genes (CEACAM8, CEACAM6, CILP2, COL17A1, OLFM4, INHBA, LCN2, LTF, MMP8, DEFA4, PRTN3, AZU1, and ELANE) were selected for validation, and a consistent trend of increased expression in responders prior to drug administration was observed for most of these genes, with findings for 4 of them being statistically significant (CEACAM8, LCN2, LTF2, and PRTN3). We identified 102 differentially expressed genes involved in the response to anti-TNF drugs in children with IBDs and validated CEACAM8, LCN2, LTF2, and PRTN3. Genes participating in defense response to Gram-negative bacterium, serine-type endopeptidase activity, and transcriptional misregulation in cancer are good candidates for anticipating the response to anti-TNF drugs in children with IBDs.

Failure of anti-TNF therapy is a real concern in children with inflammatory bowel disease (IBD) owing to the limited therapeutic arsenal. Anti-TNF drugs modulate the immune response, a key driver of chronic inflammation in IBD. Accordingly, we analyzed changes in the frequency of T-lymphocyte and cytokine levels after 6 weeks of treatment to identify potential biomarkers of response to anti-TNF drugs. We recruited 77 patients under 18 years of age diagnosed with IBD and treated with an anti-TNF drug. Using flow cytometry and multiplex ELISA, we analyzed 31 T-lymphocyte populations and four cytokines. We identified changes in 10 populations of T lymphocytes after 6 weeks of treatment. Naïve Tregs were associated with a primary response to anti-TNF drugs, while activated Tregs were associated with long-term response. Serum INF-γ levels were decreased after anti-TNF treatment in children with Crohn’s disease (CD), but not in those with ulcerative colitis (UC). The memory CD8+ Type 2 Cytotoxic T (Tc2) subset increased in non-responders with CD and the CD4+ memory Th17 cells increased in non-responders with UC. These findings could help us to understand the cellular regulation of anti-TNF therapy, to identify children at a higher risk of treatment failure, and, potentially, to develop more personalized therapeutic strategies.

The possibility of using the same genotyping technology (TaqMan) for all the genetic tests included in the new Spanish pharmacogenomics portfolio should enable the application of a multigenotyping platform to obtain a whole pharmacogenomics profile. However, HLA-typing is usually performed with other technologies and needs to be adapted to TaqMan assays. Our aim was to establish a set of TaqMan assays for correct typing of HLA-A*31:01, HLA-B*15:02, HLA-B*57:01, and HLA-B*58:01. Therefore, we searched for and selected SNVs described in different populations as surrogate markers for these HLA alleles, designed TaqMan assays, and tested in a set of samples with known HLA-A and HLA-B. HLA-A*31:01 was correctly typed with a combination of rs1061235 and rs17179220 (PPV 100%, 95% CI 84.6–100-%; NPV 100%, 95% CI 96.5–100.0%), HLA-B*15:02 with rs10484555 (PPV 100%, 95% CI 69.2–100.0%; NPV 100%, 95% CI 96.8–100.0%) and rs144012689 (PPV 100%, 95% CI 69.2–100.0%; NPV 100%, 95% CI 96.8–100.0%), and HLA-B*57:01 with rs2395029 (PPV 99.5%, 95% CI 72.9–99.3%; NPV 99.5%, 95% CI 98.3–100.0%). HLA-B*58:01 was typed using two allele-specific TaqMan probes mixed with a ß-Globin reference and treated as a genotyping assay (PPV 100.0%, 95% CI 81.5–100.0%; NPV 100%, 95% CI 96.8–100.0%). In conclusion, we demonstrated a clinically useful way to type HLA-A and HLA-B alleles included in the Spanish pharmacogenomics portfolio using TaqMan assays.