High surface IgM levels associate with shorter response to ibrutinib and BTK bypass in patients with CLL.

Chronic lymphocytic leukemia (CLL) cells have variably low surface IgM (sIgM) levels/signaling capacity, influenced by chronic antigen engagement at tissue sites. Within these low levels, CLL with relatively high sIgM (CLLhigh) progresses more rapidly than CLL with low sIgM (CLLlow). During ibrutinib therapy, surviving CLL cells redistribute into the peripheral blood and can recover sIgM expression.

Prognostic significance of FCGR2B expression for the response of DLBCL patients to rituximab or obinutuzumab treatment.

Fc γ receptor IIB (FcγRIIB) is an inhibitory molecule capable of reducing antibody immunotherapy efficacy. We hypothesized its expression could confer resistance in patients with diffuse large B-cell lymphoma (DLBCL) treated with anti-CD20 monoclonal antibody (mAb) chemoimmunotherapy, with outcomes varying depending on mAb (rituximab [R]/obinutuzumab [G]) because of different mechanisms of action. We evaluated correlates between FCGR2B messenger RNA and/or FcγRIIB protein expression and outcomes in 3 de novo DLBCL discovery cohorts treated with R plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) reported by Arthur, Schmitz, and Reddy, and R-CHOP/G-CHOP-treated patients in the GOYA trial (NCT01287741).

Single-nucleotide Fcγ receptor polymorphisms do not impact obinutuzumab/rituximab outcome in patients with lymphoma.

Single-nucleotide polymorphisms (SNPs) have been shown to influence Fcγ receptor (FcγR) affinity and activity, but their effect on treatment response is unclear. We assessed their importance in the efficacy of obinutuzumab or rituximab combined with chemotherapy in untreated advanced follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) in the GALLIUM (www.clinicaltrials.

Increased circulating resistin levels in early-onset breast cancer patients of normal body mass index correlate with lymph node negative involvement and longer disease free survival: a multi-center POSH cohort serum proteomics study.

Background: Early-onset breast cancer (EOBC) affects about one in 300 women aged 40 years or younger and is associated with worse outcomes than later onset breast cancer. This study explored novel serum proteins as surrogate markers of prognosis in patients with EOBC.

Methods: Serum samples from EOBC patients (stages 1-3) were analysed using agnostic high-precision quantitative proteomics.

Evaluation of High-Throughput Genomic Assays for the Fc Gamma Receptor Locus.

Cancer immunotherapy has been revolutionised by the use monoclonal antibodies (mAb) that function through their interaction with Fc gamma receptors (FcγRs). The low-affinity FcγR genes are highly homologous, map to a complex locus at 1p23 and harbour single nucleotide polymorphisms (SNPs) and copy number variation (CNV) that can impact on receptor function and response to therapeutic mAbs. This complexity can hinder accurate characterisation of the locus.

Stimulation of surface IgM of chronic lymphocytic leukemia cells induces an unfolded protein response dependent on BTK and SYK.

B-cell receptor (BCR) signaling plays a key role in the behavior of chronic lymphocytic leukemia (CLL). However, cellular consequences of signaling are incompletely defined. Here we explored possible links between BCR signaling and the unfolded protein response (UPR), a stress response pathway that can promote survival of normal and malignant cells.

The IGHV1-69/IGHJ3 recombinations of unmutated CLL are distinct from those of normal B cells.

IGHV1-69/51p1 is expressed by ∼ 30% of unmutated chronic lymphocytic leukemia (U-CLL) and combines with selected IGHD and IGHJ genes generating stereotypes if HCDR3 amino acid homology is > 60%. We had previously revealed stereotypic IGHV1-69/IGHJ6 rearrangements in normal naive B cells, thereby identifying potential counterparts of U-CLL. A different stereotypic IGHV1-69/IGHD3-16(RF2)/IGHJ3 rearrangement carrying the CAR(GGx)YD motif in the N1-region, recurrent in 6% IGHV1-69+ve CLL, is exceptionally sequence restricted, strongly suggestive of shared antigen recognition.

Mechanisms and clinical significance of BIM phosphorylation in chronic lymphocytic leukemia.

B-cell receptor and microenvironment-derived signals promote accumulation of chronic lymphocytic leukemia (CLL) cells through increased proliferation and/or decreased apoptosis. In this study, we investigated the regulation of BIM, a proapoptotic BCL2-related protein, which is tightly regulated by phosphorylation. Surface IgM stimulation increased phosphorylation of 2 BIM isoforms, BIM(EL) and BIM(L), in a subset of CLL samples.

Surface IgM stimulation induces MEK1/2-dependent MYC expression in chronic lymphocytic leukemia cells.

Although long considered as a disease of failed apoptosis, it is now clear that chronic lymphocytic leukemia (CLL) cells undergo extensive cell division in vivo, especially in progressive disease. Signaling via the B-cell receptor is thought to activate proliferation and survival pathways in CLL cells and also has been linked to poor outcome. Here, we have analyzed the expression of the proto-oncoprotein MYC, an essential positive regulator of the cell cycle, after stimulation of surface IgM (sIgM).

Fc gamma receptor IIb on target B cells promotes rituximab internalization and reduces clinical efficacy.

The anti-CD20 mAb rituximab is central to the treatment of B-cell malignancies, but resistance remains a significant problem. We recently reported that resistance could be explained, in part, by internalization of rituximab (type I anti-CD20) from the surface of certain B-cell malignancies, thus limiting engagement of natural effectors and increasing mAb consumption. Internalization of rituximab was most evident in chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), but the extent of internalization was heterogeneous within each disease.

Glycosylation of surface Ig creates a functional bridge between human follicular lymphoma and microenvironmental lectins.

Surface Ig (sIg) of follicular lymphoma (FL) is vital for tumor cell survival. We found previously that the Ig in FL is unusual, because the variable region genes carry sequence motifs for N-glycan addition. These are introduced by somatic mutation and are tumor specific.

Surface IgM of CLL cells displays unusual glycans indicative of engagement of antigen in vivo.

Surface IgM (sIgM) has a key influence on the clinical behavior of chronic lymphocytic leukemia (CLL). We now report that it exists in 2 forms with different N-glycosylation patterns in the mu-constant region. One glycoform is similar to normal B cells in bearing mature complex glycans common to most cell-surface glycoproteins.

The normal IGHV1-69-derived B-cell repertoire contains stereotypic patterns characteristic of unmutated CLL.

The cell of origin of chronic lymphocytic leukemia (CLL) has long been sought, and immunoglobulin gene analysis provides new clues. In the unmutated subset (U-CLL), there is increased usage of the 51p1-related alleles of the immunoglobulin heavy chain variable 1-69 gene, often combined with selected genes and with immunoglobulin heavy chain diversity IGHJ6. Stereotypic characteristics of the HCDR3 result and suggest antigen selection of the leukemic clones.

Monoclonal antibodies directed to CD20 and HLA-DR can elicit homotypic adhesion followed by lysosome-mediated cell death in human lymphoma and leukemia cells.

mAbs are becoming increasingly utilized in the treatment of lymphoid disorders. Although Fc-FcgammaR interactions are thought to account for much of their therapeutic effect, this does not explain why certain mAb specificities are more potent than others. An additional effector mechanism underlying the action of some mAbs is the direct induction of cell death.

Reversible anergy of sIgM-mediated signaling in the two subsets of CLL defined by VH-gene mutational status.

The 2 subsets of chronic lymphocytic leukemia (CLL), of worse or better prognosis, likely derive from pre-GC unmutated B cells, or post-GC mutated B cells, respectively. Different clinical behavior could relate to the ability of tumor cells to respond to surface (sIg)-mediated signals. Unmutated cases (U-CLL) have an increased ability to phosphorylate p72(Syk) in response to sIgM ligation compared to mutated cases (M-CLL).

Human follicular lymphoma cells contain oligomannose glycans in the antigen-binding site of the B-cell receptor.

Expression of surface immunoglobulin appears critical for the growth and survival of B-cell lymphomas. In follicular lymphoma, we found previously that the Ig variable (V) regions in the B-cell receptor express a strikingly high incidence of N-glycosylation sequons, NX(S/T). These potential glycosylation sites are introduced by somatic mutation and are lymphoma-specific, pointing to their involvement in tumor pathogenesis.

Structural and functional features of the B-cell receptor in IgG-positive chronic lymphocytic leukemia.

Purpose: To determine the origin and relationship of the rare IgG+ variant of chronic lymphocytic leukemia (CLL) to the two common IgM+IgD+ subsets that are distinguished by expression of unmutated or mutated V(H) genes, with the former having a worse prognosis.

Experimental Design: IgG+ CLL cells were characterized using phenotypic, functional, and immunogenetic analyses.

Results: IgG+ CLL was phenotypically similar to mutated IgM+IgD+ CLL (M-CLL) and variably expressed CD38 (4 of 14).

Antibodies selected from combinatorial libraries block a tumor antigen that plays a key role in immunomodulation.

We searched for cell-surface-associated proteins overexpressed on B cell chronic lymphocytic leukemia (CLL) to use as therapeutic antibody targets. Antibodies binding the immunosuppressive molecule CD200 were identified by cell panning of an antibody phage display library derived from rabbits immunized with primary CLL cells. B cells from 87 CLL patients exhibited 1.

The relevance of sequence insertions in the Mcl-1 promoter in chronic lymphocytic leukemia and in normal cells.

We measured the frequency of insertions in the Mcl-1 promoter in chronic lymphocytic leukemia (CLL) and in normal individuals. Insertions were found in 37/54 (69%) of the CLL samples. However, insertions were not associated with prognostic markers and were also detected in 38/66 (58%) of normal controls and in normal cells isolated from CLL patients.

Common patterns of B cell perturbation and expanded V4-34 immunoglobulin gene usage in autoimmunity and infection.

Features of the lymphocyte population in systemic lupus erythematosus (SLE) include a disordered B cell profile and production of autoantibodies. An additional distinctive perturbation is the overexpression of V4-34-encoded serum immunoglobulins (Ig). A similar rise in V4-34-encoded Ig occurs in normal subjects following infection with certain herpesviruses, and is found in Epstein-Barr virus (EBV)-associated infectious mononucleosis (IM).

Features of the overexpressed V1-69 genes in the unmutated subset of chronic lymphocytic leukemia are distinct from those in the healthy elderly repertoire.

Chronic lymphocytic leukemia (CLL) comprises 2 subsets, distinguished by expression of unmutated or mutated V(H) genes, with the former having a worse prognosis. Biased usage of the V1-69 gene is found in unmutated cases and is combined with selected D gene segments and J(H)6. It is controversial whether this is a CLL-associated feature or mirrors the normal B-cell pattern.

Evidence for involvement of a hydrophobic patch in framework region 1 of human V4-34-encoded Igs in recognition of the red blood cell I antigen.

The monoclonal IgM cold agglutinins that bind to the I/i carbohydrate Ags on the surface of RBCs all have Ig H chains encoded by the V4-34 gene segment. This mandatory use indicates that distinctive amino acid sequences may be involved in recognition. Critical amino acids exist in framework region 1 (FR1) of V4-34-encoded Ig, and these generate a specific Id determinant which apparently lies close to the I binding site.