Prognostic Role of Gene Mutations in Chronic Myelomonocytic Leukemia Patients Treated With Hypomethylating Agents

Somatic mutations contribute to the heterogeneous prognosis of chronic myelomonocytic leukemia (CMML). Hypomethylating agents (HMAs) are active in CMML, but analyses of small series failed to identify mutations predicting response or survival. We analyzed a retrospective multi-center cohort of 174 CMML patients treated with a median of 7 cycles of azacitidine (n = 68) or decitabine (n = 106). Sequencing data before treatment initiation were available for all patients, from Sanger (n = 68) or next generation (n = 106) sequencing. Overall response rate (ORR) was 52%, including complete response (CR) in 28 patients (17%). In multivariate analysis, ASXL1 mutations predicted a lower ORR (Odds Ratio [OR] = 0.85, p = 0.037), whereas TET2mut/ASXL1wt genotype predicted a higher CR rate (OR = 1.18, p = 0.011) independently of clinical parameters. With a median follow-up of 36.7 months, overall survival (OS) was 23.0 months. In multivariate analysis, RUNX1mut (Hazard Ratio [HR] = 2.00, p = .011), CBLmut (HR = 1.90, p = 0.03) genotypes and higher WBC (log10(WBC) HR = 2.30, p = .005) independently predicted worse OS while the TET2mut/ASXL1wt predicted better OS (HR = 0.60, p = 0.05). CMML-specific scores CPSS and GFM had limited predictive power. Our results stress the need for robust biomarkers of HMA activity in CMML and for novel treatment strategies in patients with myeloproliferative features and RUNX1 mutations. Keywords: Chronic myelomonocytic leukemia, Hypomethylating agents, Somatic mutations, Prognosi

Enteral feeding reduces metabolic activity of the intestinal microbiome in Crohn’s disease: an observational study

Background/Objectives: Enteral feeding will induce remission in as many as 80–90% of compliant patients with active Crohn’s disease (CD), but its method of action remains uncertain. This study was designed to examine its effects on the colonic microbiome. Methods/Subjects: Healthy volunteers and patients with CD followed a regimen confined to enteral feeds alone for 1 or 2 weeks, respectively. Chemicals excreted on breath or in faeces were characterised at the start and at the end of the feeding period by gas chromatography/mass spectrometry. Results: One week of feeding in healthy volunteers caused significant changes in stool colour and deterioration in breath odour, together with increased excretion of phenol and indoles on the breath. Feeding for 2 weeks in patients with CD produced significant improvements in symptoms and a decrease in the concentration of C-reactive protein. The faecal concentrations of microbial products, including short-chain fatty acids (SCFAs), and potentially toxic substances, including 1-propanol, 1-butanol and the methyl and ethyl esters of SCFAs, showed significant falls. Conclusions: A significant change occurs in the production of microbial metabolites after enteral feeding in both healthy volunteers and patients with CD. Many of those detected in CD are toxic and may feasibly lead to the immunological attack on the gut microbiota, which is characteristic of inflammatory bowel disease. The reduction in the production of such metabolites after enteral feeding may be the reason for its effectiveness in CD

A Key Role of Dendritic Cells in Probiotic Functionality

BACKGROUND: Disruption of the intestinal homeostasis and tolerance towards the resident microbiota is a major mechanism involved in the development of inflammatory bowel disease. While some bacteria are inducers of disease, others, known as probiotics, are able to reduce inflammation. Because dendritic cells (DCs) play a central role in regulating immune responses and in inducing tolerance, we investigated their role in the anti-inflammatory potential of probiotic lactic acid bacteria. METHODOLOGY/PRINCIPAL FINDINGS: Selected LAB strains, while efficiently taken up by DCs in vitro, induced a partial maturation of the cells. Transfer of probiotic-treated DCs conferred protection against 2, 4, 6-trinitrobenzenesulfonic acid (TNBS)-induced colitis. Protection was associated with a reduction of inflammatory scores and colonic expression of pro-inflammatory genes, while a high local expression of the immunoregulatory enzyme indolamine 2, 3 dioxgenase (IDO) was observed. The preventive effect of probiotic-pulsed DCs required not only MyD88-, TLR2- and NOD2-dependent signaling but also the induction of CD4+ CD25+ regulatory cells in an IL-10-independent pathway. CONCLUSIONS/SIGNIFICANCE: Altogether, these results suggest that selected probiotics can stimulate DC regulatory functions by targeting specific pattern-recognition receptors and pathways. The results not only emphasize the role of DCs in probiotic immune interactions, but indicate a possible role in immune-intervention therapy for IBD

Endogenous antigen presenting cell-derived IL-10 inhibits T lymphocyte responses to commensal enteric bacteria

Interleukin-10 deficient (IL-10-/-) mice develop chronic T cell-mediated colitis when colonized with normal commensal bacteria, but germ-free (GF) IL-10-/- mice remain disease-free. Antigen presenting cells (APC) secrete regulatory cytokines that help determine T lymphocyte activation or tolerance. CD4+ T cells from the mesenteric lymph nodes of inflamed IL-10-/- mice secrete more IFNγ and IL-17 when cultured with cecal bacterial lysate-pulsed splenic APC from IL-10-/- mice than when cultured with normal control APC. GF IL-10-/- APC induce similar IFNγ and IL-17 responses; therefore, the functional difference between normal and IL-10 deficient APC is inherent to the lack of IL-10 and not secondary to inflammation. Bacterial lysate-pulsed normal APC cultured with CD4+ cells from colitic IL-10-/- mice or with exogenous IFNγ secrete higher amounts of IL-10 compared to the same APC cultured with naïve T cells. APC enriched for CD11c+ cells are potent activators of IFNγ and IL-17 production by CD4+ cells from IL-10-/- mice. These APC also produce IL-12/IL-23 p40 and IL-10. Recombinant IL-10 suppressed and anti-IL-10 receptor antibody increased IFNγ, IL-17 and IL-12/IL-23 p40 production in bacterial lysate-pulsed APC and plus CD4+ T cell co-cultures. Taken together, our results show that endogenous IL-10 produced by APC inhibits responses to commensal bacteria and influences the ability of APC to stimulate IFNγ-producing effector lymphocytes, which reciprocally, induce IL-10 production by APC. Cytokines produced by APC are an important determinant of pathogenic versus protective mucosal immune responses to colonic bacterial stimulation

Foxp3(+) regulatory T cells, Th17 effector cells, and cytokine environment in inflammatory bowel disease

Background: Inflammatory bowel disease (IBD) is thought to result from an aberrant immune response. Inflammation in IBD may be caused by the loss of homeostasis between CD4+ CD25high Foxp3+ regulatory cells (T reg) and proinflammatory Th17 cells. The aim of this study was to investigate T reg and Th17 cells in the peripheral blood and intestinal mucosa of IBD patients and to assess the mucosal cytokine environment. Methods: T reg and Th17 cells were measured in peripheral blood of 63 IBD patients and 28 controls by flow cytometry. Forkhead box p3 (Foxp3), interleukin (IL)-17a, IL-1β, IL-6, IL-21, IL-23, and transforming growth factor (TGF)-β mRNA were analyzed using real-time reverse transcription polymerase chain reaction in intestinal biopsies of 24 IBD and 18 control subjects. Results: A decrease in T reg and increase in Th17 cells was observed in the peripheral blood of IBD patients. When measured in the same patient and expressed as a ratio, a significant decrease in T reg/Th17 ratio was observed in IBD. Elevated expression of Foxp3, IL-17a, IL-1β, and IL-6 was observed in the mucosa of IBD patients, while TGF-β was only elevated in ulcerative colitis. Conclusion: IBD is associated with a reduced ratio of T reg to Th17 cells in peripheral blood and is characterized by a proinflammatory cytokine microenvironment, which supports the continued generation of Th17 cells.Nicola Eastaff-Leung, Nicholas Mabarrack, Angela Barbour, Adrian Cummins and Simon Barr

T regulatory cell suppression of colitis: the role of TGF‐β

Transforming growth factor β (TGF‐β) and interleukin 2 may be involved in IBD peripheral regulatory T cell pathophysiology, raising the possibility of therapeutic application of TGF‐β induced regulatory T cells in IBD patient