B-cell receptors expressed by lymphomas of hepatitis C virus (HCV)–infected patients rarely react with the viral proteins

Abstract

Key Points• We tested the hypothesis that B-cell lymphomas arising in HCV-infected patients express B-cell receptors specific to the virus.• We analyzed the reactivity of these B-cell receptors with HCV proteins using several experimental approaches, none of which supported the hypothesis.Chronic hepatitis C virus (HCV) infection has been implicated in the induction and maintenance of B-cell lymphomas. The strongest evidence for this derives from clinical observations of tumor regressions upon antiviral treatments. Here we used multiple methods to test the hypothesis that the expansion of HCV-specific B cells gives rise to lymphomas. We obtained lymphoma tissues from HCV-infected lymphoma patients, including some that later regressed upon antiviral treatments. suggesting immunoglobulin G (IgG)'s importance for lymphoma cell survival. Yet lymphomas' cognate antigens are not known. B-cell proliferative diseases such as mixed cryoglobulinemia (MC) and B-cell non-Hodgkin lymphoma (B-NHL) that arise in hepatitis C virus (HCV)-infected patients represent a special opportunity to study antigenic drive in lymphomagenesis. First, both MC and B-NHL use a restricted V-gene repertoire shared by anti-HCV envelope antibodies.4,5 Second, elimination of HCV by antiviral therapies in patients with these B-cell diseases has been associated with their regression.6 Moreover, we previously identified an HCV-associated lymphoma whose BCR bound the HCV envelope protein E2.7 Normal B cells aimed at eliminating HCV would be expected to bind the virus via 2 receptors: the cognate BCR and the viral entry receptor CD81, which is a member of a costimulatory complex with CD19/CD21. Such B cells would receive dual stimulatory signals and might undergo unchecked proliferation during chronic HCV infection.Here we tested this hypothesis by expressing BCRs from lymphomas of HCV-infected patients as soluble IgGs, suggesting their importance, and as membrane IgMs. We included patients who had tumor regressions after antiviral therapies, 8 expecting that they would be more likely to express anti-HCV BCRs. We used several methods to test the reactivity of the rescued lymphoma BCRs with viral proteins and particles. However, we found no reactivity and therefore no evidence to support the hypothesis that viral antigens drive B-cell lymphomas. Methods PatientsBiopsy specimens of patients with B-NHL and chronic HCV infection were collected at Stanford University Medical Center, Sloan Kettering Memorial Cancer Center, and the University of Pavia Medical School. Patients' medical record numbers were de-identified and reassigned numbers. The institutional review boards at each center approved this study, and written informed consent was obtained from all patients in accordance with the Declaration of Helsinki.V-gene rescue mRNA was isolated using RNeasy (Qiagen, Valencia, CA), cDNA was amplified using SMARTer RACE (Clontech, Mountain View, CA), and The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to i...

Identification of a novel stereotypic IGHV4-59/IGHJ5-encoded B-cell receptor subset expressed by various B-cell lymphomas with high affinity rheumatoid factor activity

“…Using the NCBI Protein-BLAST algorithm and literature IGHV searching, in addition, we also identified an ocular adnexal MALT lymphoma 17 and a DLBCL, 18 expressing highly similar VHCDR3s, encoded by IGHV4-59/IGHJ5 rearrangements ( Figure 1B). The frequency of this new stereotypic BCR group is high in the HCV-related lymphoma series of Ng et al 16 (3/19 = 15.8%) but low in DLBCL (1/483 = 0.2%) and in ocular adnexal MALT lymphoma (1/199 = 0.5%), whereas it has as yet not been identified in other B-cell lymphoma entities. An overview of all IGHV sequences used to search for the new stereotypic VH-CDR3 is provided in the Online Supplementary Table S1.…”

“…Their binding characteristics are fully comparable with those of two stereotypic V1-69-RFs derived from Sjögren's syndrome-related lymphomas and contrast with the broad polyreactivity of an IgM derived from an IGV-unmutated CLL (Figure 2). Moreover, within the series of 19 HCV-related B-cell lymphomas described by Ng et al, 16 as many as eight lymphomas express stereotypic RFs, five of which belong to known stereotypic RF subsets, i.e. two WOL-RFs, one V1-69-RF and two V4-59-RFs, and three representing the novel stereotypic IGHV4-59/IGHJ5-encoded subset.…”

“…Recently, Ng et al 16 reported that the recombinantly produced BCRs, such as IgG1 antibodies, of 19 B-cell lymphomas of HCV-infected patients did not react with HCV proteins nor displayed RF reactivity. Prompted by this observation, we analyzed their published IGHVrearrangements for VH-CDR3 stereotypy, in particular for RF stereotypy.…”

Hepatitis C virus-associated B-cell non-Hodgkin’s lymphomas: what do we know?

“…The ability of HCV to stimulate B-cell proliferation finds confirmation in numerous reports [Weng and Levy, 2003;Rosa et al 2005;Ng et al 2014]. While some studies confirm that the double binding of CD19/CD21/CD81 complex (via HCV-E2 protein) and the B-cell receptor (BCR, by specific HCV antigens) results in a reduced threshold for B-cell activation and proliferation [Weng and Levy, 2003], others suggest that the engagement of CD81 may be sufficient to elicit the B-cell proliferation even in the absence of a BCR coligation and the BCR involvement in this context remains controversial [Rosa et al 2005].…”

“…A restricted combination of the IGHV gene repertoire expressed in the monoclonal rheumatoid factor-like IgM component of the type II MC and in monoclonal antibodies from patients with HCV infection has been detected, with high frequency of V regions encoded by IGHV1-69 and IGHVk3-A27 [Gorevic and Frangione, 1991;Allander et al 2000;Libra et al 2010]. Also HCVNHLs have been found to express analogue regions of the IgV genes [Ng et al 2014]. HCV-associated NHLs may derive from B-cell clones activated during HCV infection (the malignant counterpart of type II MC), which following additional genomic alterations can develop into overt lymphoma [Libra et al 2008].…”