Control of the specificity of T cell-mediated anti-idiotype immunity by natural regulatory T cells

The idiotypes of B cell lymphomas represent tumor-specific antigens. T cell responses induced by idiotype vaccination in vivo are directed predominantly against CDR peptides, whereas in vitro T cells also recognize framework-derived epitopes. To investigate the mechanisms regulating the specificity of idiotype-specific T cells, BALB/c or B10.D2 mice were immunized with mature dendritic cells loaded with H-2Kd-restricted peptides from influenza hemagglutinin, or from shared (J region) or unique (CDR3) structures of the A20 lymphoma idiotype. Antigen-specific T cells were induced in vivo by the CDR3 and influenza epitopes, but not by the J peptide. Gene expression profiling of splenic regulatory T cells revealed vaccination-induced Treg activation and proliferation. Treg activity involved J epitope-dependent IL-10 secretion and functional suppression of peptide-specific effector T cells. Vaccination-induced in vivo proliferation of transgenic hemagglutinin-specific T cells was suppressed by co-immunization with the J peptide and was restored in CD25-depleted animals. In conclusion, Treg induced by a shared idiotype epitope can systemically suppress T cell responses against idiotype-derived and immunodominant foreign epitopes in vivo. The results imply that tumor vaccines should avoid epitopes expressed by normal cells in the draining lymph node to achieve optimal anti-tumor efficacy

Long-term results and GvHD after prophylactic and preemptive donor lymphocyte infusion after allogeneic stem cell transplantation for acute leukemia

We report on 318 patients with acute leukemia, receiving donor lymphocyte infusion (DLI) in complete hematologic remission (CHR) after allogeneic stem cell transplantation (alloSCT). DLI were applied preemptively (preDLI) for minimal residual disease (MRD, n = 23) or mixed chimerism (MC, n = 169), or as prophylaxis in high-risk patients with complete chimerism and molecular remission (proDLI, n = 126). Median interval from alloSCT to DLI1 was 176 days, median follow-up was 7.0 years. Five-year cumulative relapse incidence (CRI), non-relapse mortality (NRM), leukemia-free and overall survival (LFS/OS) of the entire cohort were 29.1%, 12.7%, 58.2%, and 64.3%. Cumulative incidences of acute graft-versus-host disease (aGvHD) grade II–IV°/chronic GvHD were 11.9%/31%. Nineteen patients (6%) died from DLI-induced GvHD. Age ≥60 years (p = 0.046), advanced stage at transplantation (p = 0.003), shorter interval from transplantation (p = 0.018), and prior aGvHD ≥II° (p = 0.036) were risk factors for DLI-induced GvHD. GvHD did not influence CRI, but was associated with NRM and lower LFS/OS. Efficacy of preDLI was demonstrated by decreasing MRD/increasing blood counts in 71%, and increasing chimerism in 70%. Five-year OS after preDLI for MRD/MC was 51%/68% among responders, and 37% among non-responders. The study describes response and outcome of DLI in CHR and helps to identify candidates without increased risk of severe GvHD

MYD88 mutations identify a molecular subgroup of diffuse large B-cell lymphoma with an unfavorable prognosis

The 2016 World Health Organization classification defines diffuse large B-cell lymphoma (DLBCL) subtypes based on Epstein-Barr virus (EBV) infection and oncogenic rearrangements of MYC/BCL2/BCL6 as drivers of lymphomagenesis. A subset of DLBCL, however, is characterized by activating mutations in MYD88/CD79B. We investigated whether MYD88/CD79B mutations could improve the classification and prognostication of DLBCL. In 250 primary DLBCL, MYD88/CD79B mutations were identified by allele-specific polymerase chain reaction or next-generationsequencing, MYC/BCL2/BCL6 rearrangements were analyzed by fluorescence in situ hybridization, and EBV was studied by EBV-encoded RNA in situ hybridization. Associations of molecular features with clinicopathologic characteristics, outcome, and prognosis according to the International Prognostic Index (IPI) were investigated. MYD88 and CD79B mutations were identified in 29.6% and 12.3%, MYC, BCL2, and BCL6 rearrangements in 10.6%, 13.6%, and 20.3%, and EBV in 11.7% of DLBCL, respectively. Prominent mutual exclusivity between EBV positivity, rearrangements, and MYD88/CD79B mutations established the value of molecular markers for the recognition of biologically distinct DLBCL subtypes. MYD88-mutated DLBCL had a significantly inferior 5-year overall survival than wild-type MYD88 DLBCL (log-rank; P=0.019). DLBCL without any of the studied aberrations had superior overall survival compared to cases carrying .1 aberrancy (log-rank; P=0.010). MYD88 mutations retained their adverse prognostic impact upon adjustment for other genetic and clinical variables by multivariable analysis and improved the prognostic performance of the IPI. This study demonstrates the clinical utility of defining MYD88-mutated DLBCL as a distinct molecular subtype with adverse prognosis. Our data call for sequence analysis of MYD88 in routine diagnostics of DLBCL to optimize classification and prognostication, and to guide the development of improved treatment strategies

Outcome after relapse of myelodysplastic syndrome and secondary acute myeloid leukemia following allogeneic stem cell transplantation : a retrospective registry analysis on 698 patients by the Chronic Malignancies Working Party of the European Society of Blood and Marrow Transplantation

No standard exists for the treatment of myelodysplastic syndrome relapsing after allogeneic stem cell transplantation. We performed a retrospective registry analysis of outcomes and risk factors in 698 patients, treated with different strategies. The median overall survival from relapse was 4.7 months (95% confidence interval: 4.1-5.3) and the 2-year survival rate was 17.7% (95% confidence interval: 14.8-21.2%). Shorter remission after transplantation (PPeer reviewe

Long-term survival and late events after allogeneic stem cell transplantation from HLA-matched siblings for acute myeloid leukemia with myeloablative compared to reduced-intensity conditioning : a report on behalf of the acute leukemia working party of European group for blood and marrow transplantation

Background: Myeloablative (MAC) and reduced-intensity conditioning (RIC) are established approaches for allogeneic stem cell transplantation (SCT) in acute myeloid leukemia (AML). Most deaths after MAC occur within the first 2 years after SCT, while patients surviving leukemia-free for 2 years can expect a favorable long-term outcome. However, there is paucity of data on the long-term outcome (beyond 10 years) and the pattern of late events following RIC due to the relative recent introduction of this approach. Methods: We analyzed long-term outcomes in a cohort of 1423 AML patients, age >= 50 years, after SCT from HLA-matched siblings, during the years 1997-2005, median follow-up 8.3 years (0.1-17). Results: The 10-year leukemia-free survival (LFS) was 31 % (95CI, 27-35) and 32 % (28-35) after MAC and RIC, respectively (P = 0.57). The 10-year GVHD/relapse-free survival (GRFS), a surrogate for quality of life was 22 % (18-25) and 21 % (18-24), respectively (P = 0.79). The 10-year non-relapse mortality (NRM) was higher and relapse rate was lower after MAC, throughout the early and late post-transplant course. The 10-year LFS among 584 patients surviving leukemia-free 2 years after SCT was 71 % (65-76) and 73 % (67-78) after MAC and RIC, respectively (P = 0.76). Advanced leukemia at SCT was the major predictor of LFS subsequent to the 2-year landmark. Relapse was the major cause of late death after both regimens; however, NRM and in particular chronic graft-versus-host disease and second cancers were more common causes of late death after MAC. Conclusions: Long-term LFS and GRFS are similar after RIC and MAC. Most events after RIC or MAC occur within the first 2 years after SCT. Patients who are leukemia-free 2 years after SCT can expect similar good subsequent outcome after both approaches.Peer reviewe

Frequent mutated B2M, EZH2, IRF8, and TNFRSF14 in primary bone diffuse large B-cell lymphoma reflect a GCB phenotype

Primary bone diffuse large B-cell lymphoma (PB-DLBCL) is a rare extranodal lymphoma subtype. This retrospective study elucidates the currently unknown genetic background of a large clinically well-annotated cohort of DLBCL with osseous localizations (O-DLBCL), including PB-DLBCL. A total of 103 patients with O-DLBCL were included and compared with 63 (extra)nodal non-osseous (NO)-DLBCLs with germinal center B-cell phenotype (NO-DLBCL-GCB). Cell-of-origin was determined by immunohistochemistry and gene-expression profiling (GEP) using (extended)-NanoString/Lymph2Cx analysis. Mutational profiles were identified with targeted next-generation deep sequencing, including 52 B-cell lymphoma-relevant genes. O-DLBCLs, including 34 PB-DLBCLs, were predominantly classified as GCB phenotype based on immunohistochemistry (74%) and NanoString analysis (88%). Unsupervised hierarchical clustering of an extended-NanoString/Lymph2Cx revealed significantly different GEP clusters for PB-DLBCL as opposed to NO-DLBCL-GCB (P < .001). Expression levels of 23 genes of 2 different targeted GEP panels indicated a centrocyte-like phenotype for PB-DLBCL, whereas NO-DLBCL-GCB exhibited a centroblast-like constitution. PB-DLBCL had significantly more frequent mutations in four GCB-associated genes (ie, B2M, EZH2, IRF8, TNFRSF14) compared with NO-DLBCL-GCB (P = .031, P = .010, P = .047, and P = .003, respectively). PB-DLBCL, with its corresponding specific mutational profile, was significantly associated with a superior survival compared with equivalent Ann Arbor limited-stage I/II NO-DLBCL-GCB (P = .016). This study is the first to show that PB-DLBCL is characterized by a GCB phenotype, with a centrocyte-like GEP pattern and a GCB-associated mutational profile (both involved in immune surveillance) and a favorable prognosis. These novel biology-associated features provide evidence that PB-DLBCL represents a distinct extranodal DLBCL entity, and its specific mutational landscape offers potential for targeted therapies (eg, EZH2 inhibitors)

IGLV3-21*01 is an inherited risk factor for CLL through the acquisition of a single-point mutation enabling autonomous BCR signaling

The prognosis of chronic lymphocytic leukemia (CLL) depends on different markers, including cytogenetic aberrations, oncogenic mutations, and mutational status of the immunoglobulin (Ig) heavy-chain variable (IGHV) gene. The number of IGHV mutations distinguishes mutated (M) CLL with a markedly superior prognosis from unmutated (UM) CLL cases. In addition, B cell antigen receptor (BCR) stereotypes as defined by IGHV usage and complementarity-determining regions (CDRs) classify ∼30% of CLL cases into prognostically important subsets. Subset 2 expresses a BCR with the combination of IGHV3-21-derived heavy chains (HCs) with IGLV3-21-derived light chains (LCs), and is associated with an unfavorable prognosis. Importantly, the subset 2 LC carries a single-point mutation, termed R110, at the junction between the variable and constant LC regions. By analyzing 4 independent clinical cohorts through BCR sequencing and by immunophenotyping with antibodies specifically recognizing wild-type IGLV3-21 and R110-mutated IGLV3-21 (IGLV3-21R110), we show that IGLV3-21R110-expressing CLL represents a distinct subset with poor prognosis independent of IGHV mutations. Compared with other alleles, only IGLV3-21*01 facilitates effective homotypic BCR-BCR interaction that results in autonomous, oncogenic BCR signaling after acquiring R110 as a single-point mutation. Presumably, this mutation acts as a standalone driver that transforms IGLV3-21*01-expressing B cells to develop CLL. Thus, we propose to expand the conventional definition of CLL subset 2 to subset 2L by including all IGLV3-21R110-expressing CLL cases regardless of IGHV mutational status. Moreover, the generation of monoclonal antibodies recognizing IGLV3-21 or mutated IGLV3-21R110 facilitates the recognition of B cells carrying this mutation in CLL patients or healthy donors