Infliximab to treat Crohn's disease: an update

Levels of Intestinal Inflammation and Fibrosis in Resection Specimens after Preoperative Anti-Tumor Necrosis Factor Alpha Treatment in Patients with Crohn's Disease: A Comparative Pilot Study

Background

Strictures are a common complication in Crohn's disease (CD), found in more than 50% of patients. They are characterized by the excessive deposition of extracellular proteins in the tissue as a result of the chronic inflammatory process. The effect of anti-tumor necrosis factor alpha (TNF-α) therapy on the development of fibrosis is not yet fully understood.

Aim

To investigate whether the degree of intestinal inflammation and fibrosis is correlated with preoperative anti-TNF-α) therapy on the development of fibrosis is not yet fully understood.

Methods

This unblinded, prospective, single tertiary center, pilot cohort study included all adult patients with CD who underwent elective, laparoscopic, or open intestinal resection. Preoperative investigations included measurement of blood TNF-α) therapy on the development of fibrosis is not yet fully understood.

Results

Histopathological specimens from 10 patients with CD who underwent ileocecal or ileocolic resections were retrieved. Four of those patients were on anti-TNF-α) therapy on the development of fibrosis is not yet fully understood. α) therapy on the development of fibrosis is not yet fully understood. α) therapy on the development of fibrosis is not yet fully understood. p=0.01). Anti-TNF-α) therapy on the development of fibrosis is not yet fully understood. α) therapy on the development of fibrosis is not yet fully understood. α) therapy on the development of fibrosis is not yet fully understood.

Conclusions

Patients who underwent preoperative anti-TNF-α treatment had a higher fibrosis score than controls.α) therapy on the development of fibrosis is not yet fully understood.

Functional rare variants influence the clinical response to anti-TNF therapy in Crohn's disease

BACKGROUND

The effect of low-frequency functional variation on anti-tumor necrosis factor alpha (TNF) response in Crohn's disease (CD) patients remains unexplored. The objective of this study was to investigate the impact of functional rare variants in clinical response to anti-TNF therapy in CD.

METHODS

CD anti-TNF naïve patients starting anti-TNF treatment due to active disease [Crohn's Disease Activity Index (CDAI > 150)] were included. The whole genome was sequenced using the Illumina Hiseq4000 platform. Clinical response was defined as a CDAI score <150 at week 14 of anti-TNF treatment. Low-frequency variants were annotated and classified according to their damaging potential. The whole genome of CD patients was screened to identify homozygous loss-of-function (LoF) variants. The TNF signaling pathway was tested for overabundance of damaging variants using the SKAT-O method. Functional implication of the associated rare variation was evaluated using cell-type epigenetic enrichment analyses.

RESULTS

A total of 41 consecutive CD patients were included; 3250 functional rare variants were identified (2682 damaging and 568 LoF variants). Two homozygous LoF mutations were found in HLA-B and HLA-DRB1 genes associated with lack of response and remission, respectively. Genome-wide LoF variants were enriched in epigenetic marks specific for the gastrointestinal tissue (colon, p = 4.11e-4; duodenum, p = 0.011). The burden of damaging variation in the TNF signaling pathway was associated with response to anti-TNF therapy (p = 0.016); damaging variants were enriched in epigenetic marks from CD8⁺ (p = 6.01e-4) and CD4+ (p = 0.032) T cells.

CONCLUSIONS

Functional rare variants are involved in the response to anti-TNF therapy in CD. Cell-type enrichment analysis suggests that the gut mucosa and CD8⁺ T cells are the main mediators of this response.

Response to Infliximab in Crohn's Disease: Genetic Analysis Supporting Expression Profile

Substantial proportion of Crohn's disease (CD) patients shows no response or a limited response to treatment with infliximab (IFX) and to identify biomarkers of response would be of great clinical and economic benefit. The expression profile of five genes (S100A8-S100A9, G0S2, TNFAIP6, and IL11) reportedly predicted response to IFX and we aimed at investigating their etiologic role through genetic association analysis. Patients with active CD (350) who received at least three induction doses of IFX were included and classified according to IFX response. A tagging strategy was used to select genetic polymorphisms that cover the variability present in the chromosomal regions encoding the identified genes with altered expression. Following genotyping, differences between responders and nonresponders to IFX were observed in haplotypes of the studied regions: S100A8-S100A9 (rs11205276^*G/rs3014866^*C/rs724781^*C/rs3006488^*A; P = 0.05); G0S2 (rs4844486^*A/rs1473683^*T; P = 0.15); TNFAIP6 (rs11677200^*C/rs2342910^*A/rs3755480^*G/rs10432475^*A; P = 0.10); and IL11 (rs1126760^*C/rs1042506^*G; P = 0.07). These differences were amplified in patients with colonic and ileocolonic location for all but the TNFAIP6 haplotype, which evidenced significant difference in ileal CD patients. Our results support the role of the reported expression signature as predictive of anti-TNF outcome in CD patients and suggest an etiological role of those top-five genes in the IFX response pathway.

Nitrosothiols in the immune system: signaling and protection

SIGNIFICANCE

In the immune system, nitric oxide (NO) has been mainly associated with antibacterial defenses exerted through oxidative, nitrosative, and nitrative stress and signal transduction through cyclic GMP-dependent mechanisms. However, S-nitrosylation is emerging as a post-translational modification (PTM) involved in NO-mediated cell signaling.

RECENT ADVANCES

Precise roles for S-nitrosylation in signaling pathways have been described both for innate and adaptive immunity. Denitrosylation may protect macrophages from their own S-nitrosylation, while maintaining nitrosative stress compartmentalized in the phagosomes. Nitrosothiols have also been shown to be beneficial in experimental models of autoimmune diseases, mainly through their role in modulating T-cell differentiation and function.

CRITICAL ISSUES

Relationship between S-nitrosylation, other thiol redox PTMs, and other NO-signaling pathways has not been always taken into account, particularly in the context of immune responses. Methods for assaying S-nitrosylation in individual proteins and proteomic approaches to study the S-nitrosoproteome are constantly being improved, which helps to move this field forward.

FUTURE DIRECTIONS

Integrated studies of signaling pathways in the immune system should consider whether S-nitrosylation/denitrosylation processes are among the PTMs influencing the activity of key signaling and adaptor proteins. Studies in pathophysiological scenarios will also be of interest to put these mechanisms into broader contexts. Interventions modulating nitrosothiol levels in autoimmune disease could be investigated with a view to developing new therapies.

Clinically silent Crohn's disease in a patient with Takayasu's arteritis unresponsive to conventional therapies

Takayasu arteritis (TA) and Crohn's disease (CD) are chronic inflammatory diseases with granulomatous nature. Here, we report a case of TA with a silent course of CD who was refractory to corticosteroid and immunosuppressive treatments and improved with adalimumab therapy.