Background– Preclinical and preliminary clinical data have suggested that tumor necrosis factor-α (TNFα) may play a role in the evolution and progression of heart failure and that inhibition of TNFα may favorably modify the course of the disease. We evaluated the efficacy and safety of infliximab, a chimeric monoclonal antibody to TNFα, in patients with moderate-to-severe heart failure. Methods and Results– One hundred fifty patients with stable New York Heart Association class III or IV heart failure and left ventricular ejection fraction ≤35% were randomly assigned to receive placebo (n=49), infliximab 5 mg/kg (n=50), or infliximab 10 mg/kg (n=51) at 0, 2, and 6 weeks after randomization and were followed-up prospectively for 28 weeks. Neither dose of infliximab improved clinical status at 14 weeks, the primary endpoint of the study, despite suppression of inflammatory markers (C-reactive protein and interleukin-6) and a modest increase in ejection fraction in the patients receiving 5 mg/kg ( P =0.013). Furthermore, after 28 weeks, 13, 10, and 20 patients were hospitalized for any reason in the placebo, 5 mg/kg infliximab, and 10 mg/kg infliximab groups, respectively. The combined risk of death from any cause or hospitalization for heart failure through 28 weeks was increased in the patients randomized to 10 mg/kg infliximab (hazard ratio 2.84, 95% confidence interval 1.01 to 7.97; nominal P =0.043). Conclusions– Short-term TNFα antagonism with infliximab did not improve and high doses (10 mg/kg) adversely affected the clinical condition of patients with moderate-to-severe chronic heart failure.

Randomized, Double-Blind, Placebo-Controlled, Pilot Trial of Infliximab, a Chimeric Monoclonal Antibody to Tumor Necrosis Factor-α, in Patients With Moderate-to-Severe Heart Failure Results of the Anti-TNF Therapy Against Congestive Heart failure (ATTACH) Trial

BACKGROUND/AIM Proinflammatory cytokines are key factors in the pathogenesis of Crohn9s disease (CD). Activation of nuclear factor kappa B (NFκB), which is involved in their gene transcription, is increased in the intestinal mucosa of CD patients. As butyrate enemas may be beneficial in treating colonic inflammation, we investigated if butyrate promotes this effect by acting on proinflammatory cytokine expression. METHODS Intestinal biopsy specimens, isolated lamina propria cells (LPMC), and peripheral blood mononuclear cells (PBMC) were cultured with or without butyrate for assessment of secretion of tumour necrosis factor (TNF) and mRNA levels. NFκB p65 activation was determined by immunofluorescence and gene reporter experiments. Levels of NFκB inhibitory protein (IκBα) were analysed by western blotting. The in vivo efficacy of butyrate was assessed in rats with trinitrobenzene sulphonic acid (TNBS) induced colitis. RESULTS Butyrate decreased TNF production and proinflammatory cytokine mRNA expression by intestinal biopsies and LPMC from CD patients. Butyrate abolished lipopolysaccharide (LPS) induced expression of cytokines by PBMC and transmigration of NFκB from the cytoplasm to the nucleus. LPS induced NFκB transcriptional activity was decreased by butyrate while IκBα levels were stable. Butyrate treatment also improved TNBS induced colitis. CONCLUSIONS Butyrate decreases proinflammatory cytokine expression via inhibition of NFκB activation and IκBα degradation. These anti-inflammatory properties provide a rationale for assessing butyrate in the treatment of CD.

https://gut.bmj.com/content/gutjnl/47/3/397.full.pdf

Butyrate inhibits inflammatory responses through NFκB inhibition: implications for Crohn's disease

The T helper lymphocyte is responsible for orchestrating the appropriate immune response to a wide variety of pathogens. The recognition of the polarized T helper cell subsets Th1 and Th2 has led to an understanding of the role of these cells in coordinating a variety of immune responses, both in responses to pathogens and in autoimmune and allergic disease. Here, we discuss the mechanisms that control lineage commitment to the Th1 phenotype. What has recently emerged is a rich understanding of the cytokines, receptors, signal transduction pathways, and transcription factors involved in Th1 differentiation. Although the picture is still incomplete, the basic pathways leading to Th1 differentiation can now be understood in in vitro and a number of infection and disease models.

Molecular Mechanisms RegulatinG Th1 Immune Responses

Genome-wide association studies efficiently and powerfully assay common genetic variation. The application of these studies to Crohn's disease has provided insight into the immunopathogenesis of this disease, implicating a role for genes of the innate and adaptive immune systems. In this Review, I discuss our current understanding of the genetics and immunopathogenesis of Crohn's disease and ulcerative colitis. Crohn's disease, but not ulcerative colitis, is associated with genetic variation in NOD2 and an autophagy gene, ATG16L1, both of which affect the intracellular processing of bacterial components. By contrast, variation in the gene encoding the interleukin-23 (IL-23) receptor subunit, as well as in the IL12B, STAT3 and NKX2-3 gene regions, is associated with both Crohn's disease and ulcerative colitis. Comparative analyses of gene associations between these two inflammatory bowel diseases reveal common and unique mechanisms of their immunopathogenesis.

The genetics and immunopathogenesis of inflammatory bowel disease

https://onlinelibrary.wiley.com/doi/pdf/10.1002/jps.20178

Antibody pharmacokinetics and pharmacodynamics.

Recent clinical studies of Crohn's disease patients demonstrated dramatic clinical responses following one i.v. infusion of a chimeric mAb to TNF-alpha (cA2). To assess the role of TNF-alpha in mucosal cytokine regulation, the effects of TNF-alpha on lamina propria mononuclear cell (LPMC) Th1 production were determined. Increased IFN-gamma production was demonstrated in anti-CD2-stimulated LPMC cultured in TNF-alpha. To determine the effects of cA2 on cytokine production, TNF-alpha- and IFN-gamma-producing cells were quantitated in LPMC from five Crohn's disease patients treated with cA2. In all four patients who demonstrated clinical and endoscopic improvement, decreased numbers of LPMC producing IFN-gamma and TNF-alpha following CD2/CD28 activation paralleled improvement in disease activity over 8 wk. In one patient who did not improve, increased numbers of TNF-alpha- and IFN-gamma-secreting LPMC were observed. In three of four responding patients, CD2/CD28-activated PBMC demonstrated increased IFN-gamma production over 8 wk. These observations suggest that TNF-alpha may be a cofactor for mucosal Th1 responses, and improvement in clinical parameters and intestinal inflammation induced by cA2 in Crohn's disease may be mediated by down-regulation of mucosal Th1 cytokines.

A role for TNF-alpha and mucosal T helper-1 cytokines in the pathogenesis of Crohn's disease.

Background:

Anti-TNFα therapy with infliximab is effective for Crohn’s disease. Infliximab neutralizes the biological activities of TNFα, a cytokine involved in host-defence against certain infections.



Aim:

To evaluate the effects of infliximab on the gut and peripheral immune system functions.



Methods:

Biopsies and blood samples from three clinical trials of infliximab in Crohn’s disease were analysed. Pharmacokinetics, changes in leucocyte counts and T cell subsets, T cell function, and cytokine profiles of lamina propria mononuclear cells (LPMC) and peripheral blood mononuclear cells (PBMC) were analysed.



Results:

Infliximab has a serum half-life of 9.5 days and is still detectable in serum 8 weeks after infusion. Leucocyte counts showed consistent changes from baseline toward normal values after therapy. Monocytes and lymphocytes were modestly increased, while neutrophils were decreased 4 weeks after treatment. Lymphocyte subsets and T cell proliferative responses were not altered after therapy. The proportion of PBMCs capable of producing IFNγ and TNFα did not change, while Th1 cytokine production by stimulated LPMC was decreased after infliximab therapy.



Conclusion:

The clinical efficacy of infliximab is based on local anti-inflammatory and immunomodulatory effects in the bowel mucosa, without generalized suppression of systemic immune functions in Crohn’s disease patients.

D. Shealy

Papers

A role for TNF-alpha and mucosal T helper-1 cytokines in the pathogenesis of Crohn's disease.

Infliximab induces potent anti-inflammatory and local immunomodulatory activity but no systemic immune suppression in patients with Crohn's disease.