Genome-wide DNA methylation in chronic myeloid leukaemia

Epigenetic alterations occur frequently in leukaemia and might account for differences in clinical phenotype and response to treatment. Despite the consistent presence of the BCR-ABL1 fusion gene in Philadelphia-positive chronic myeloid leukaemia (CML), the clinical course of patients treated with tyrosine kinase inhibitors (TKI) is heterogeneous. This might be due to differing DNA methylation profiles between patients. Therefore, a validated, epigenome-wide survey in CML CD34+ progenitor cells was performed in newly diagnosed chronic phase patients using array-based DNA methylation and gene expression profiling. In practice, the CML DNA methylation signature was remarkably homogeneous; it differed from CD34+ cells of normal persons and did not correlate with an individual patient’s response to TKI therapy. Using a meta-analysis tool it was possible to demonstrate that this signature was highly enriched for developmentally dynamic regions of the human methylome and represents a combination of CML-unique, myeloid leukemia-specific and pan-cancer sub-signatures. The CML profile involved aberrantly methylated genes in signaling pathways already implicated in CML leukaemogenesis, including TGF-beta, Wnt, Jak-STAT and MAPK. Furthermore, a core set of differentially methylated promoters were identified that likely have a role in modulating gene expression levels. In conclusion, the findings are consistent with the notion that CML starts with the acquisition of a BCR-ABL1 fusion gene by a haematopoietic stem cell, which then either causes or cooperates with a series of DNA methylation changes that are specific for CML.Open Acces

Are Helicobacter Species and Enterotoxigenic Bacteroides fragilis Involved in Inflammatory Bowel Disease?

The aim of this study was to determine if either Helicobacter or enterotoxigenic Bacteroides fragilis (ETBF) was linked to inflammatory bowel disease (IBD), using PCR. We analyzed the luminal washings and colonic biopsies of 35 patients with IBD and 37 control patients. The presence of Helicobacter was confirmed in the luminal washing of one IBD patient and three control patients and in the biopsies of two IBD patients. Ten of 28 control patients and 8 of 32 IBD patients had a positive luminal washing for the enterotoxin gene. Six of 33 control patients and 4 of 32 IBD patients had positive biopsies. The prevalence of the enterotoxin gene was higher in IBD patients with active disease compared with patients with inactive disease, although it did not achieve statistical significance. In conclusion, Helicobacter was not associated with IBD in our population of patients, although ETBF may be associated with active disease

Prognostic Impact of Natural Killer Cell Count in Follicular Lymphoma and Diffuse Large B-cell Lymphoma Patients Treated with Immunochemotherapy

Purpose: Natural killer (NK) cells are key effector cells for anti-CD20 monoclonal antibodies (mAb), such as obinutuzumab and rituximab. We assessed whether low pretreatment NK-cell count (NKCC) in peripheral blood or tumor tissue was associated with worse outcome in patients receiving antibodybased therapy. Patients and Methods: Baseline peripheral blood NKCC was assessed by flow cytometry (CD3(-) CD56(+) and/or CD16(+) cells) in 1,064 of 1,202 patients with follicular lymphoma treated with obinutuzumab or rituximab plus chemotherapy in the phase III GALLIUM trial (NCT01332968) and 1,287 of 1,418 patients with diffuse large B-cell lymphoma (DLBCL) treated with obinutuzumab or rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (G-CHOP or R-CHOP) in the phase III GOYA trial (NCT01287741). The prognostic value of tumor NK-cell gene expression, as assessed by whole-transcriptome gene expression using TruSeq RNA sequencing, was also analyzed. The association of baseline variables, such as treatment arm, was evaluated using multivariate Cox regression models using a stepwise approach. Results: In this exploratory analysis, low baseline peripheral blood NKCC was associated with shorter progression-free survival (PFS) in both follicular lymphoma [hazard ratio (HR), 1.48; 95% confidence interval (CI), 1.02-2.14; P = 0.04] and DLBCL (HR, 1.36; 95% CI, 1.01-1.83; P = 0.04), and overall survival in follicular lymphoma (HR, 2.20; 95% CI, 1.26-3.86; P = 0.0058). Low tumor NK-cell gene expression was associated with shorter PFS in G-CHOP-treated patients with DLBCL (HR, 1.95; 95% CI, 1.22-3.15; P < 0.01). Conclusions: These findings indicate that the number of NK cells in peripheral blood may affect the outcome of patients with B-cell non-Hodgkin lymphoma receiving anti-CD20 based immunochemotherapy

Mode of progression after first line treatment correlates with outcome of chronic lymphocytic leukemia (CLL)

In CLL, progressive disease (PD) following remission after first line treatment can present with varying phenotypes. We hypothesized that the mode of PD correlates with clinical outcomes. Data from three phase III trials of the German CLL Study Group (GCLLSG) (CLL8, CLL10, CLL11) including a total of 2159 patients receiving first line (immuno)-chemotherapy (FCR, FC, CLB, CLB-R, CLB-Ob) were analyzed. Patients were categorized as ALC if PD was due to increasing absolute lymphocyte count, or as Ly if due to lymphadenopathy. A group of 241 patients progressed with ALC, and 727 progressed with Ly, including 329 who progressed on both modalities. In fit patients, median TTNT after PD in the Ly group was 12.3 months vs 17.0 months in the ALC group (HR 1.299 [1.036-1.628]; P = .024). Median OS after PD was 45.1 months in the Ly group and 42.4 months in the ALC group (HR=1.023 [0.753-1.389]; P = .885). For unfit patients, median TTNT in the Ly group was 11.7 months vs 21.4 months in the ALC group (HR 1.357 [1.051-1.753]; P = .019). Median OS was 42.8 months in the Ly group and not reached in the ALC group (HR 1.851 [1.280-2.677]; P = .001). Patients in the Ly group more frequently showed impairment of quality of life (QoL). This analysis demonstrates that patients with progressive lymphadenopathy have a significantly shorter TTNT, OS and less favorable QoL. Our findings might help physicians to better estimate the clinical course of a progressing CLL patient

Tyrosine kinase inhibitors impair B-cell immune responses in CML through off-target inhibition of kinases important for cell signaling

Tyrosine kinase inhibitors (TKIs) have significant off-target multikinase inhibitory effects. We aimed to study the impact of TKIs on the in vivo B-cell response to vaccination. Cellular and humoral responses to influenza and pneumococcal vaccines were evaluated in 51 chronic phase chronic myeloid leukemia (CML) patients on imatinib, or second-line dasatinib and nilotinib, and 24 controls. Following vaccination, CML patients on TKI had significant impairment of IgM humoral response to pneumococcus compared with controls (IgM titer 79.0 vs 200 U/mL, P = .0006), associated with significantly lower frequencies of peripheral blood IgM memory B cells. To elucidate whether CML itself or treatment with TKI was responsible for the impaired humoral response, we assessed memory B-cell subsets in paired samples collected before and after imatinib therapy. Treatment with imatinib was associated with significant reductions in IgM memory B cells. In vitro coincubation of B cells with plasma from CML patients on TKI or with imatinib, dasatinib, or nilotinib induced significant and dose-dependent inhibition of Bruton's tyrosine kinase and indirectly its downstream substrate, phospholipase-C-gamma 2, both important in B-cell signaling and survival. These data indicate that TKIs, through off-target inhibition of kinases important in B-cell signaling, reduce memory B-cell frequencies and induce significant impairment of B-cell responses in CML.</p