Peripheral B-cell CD5 expansion and CD81 overexpression and their association with disease severity and autoimmune markers in chronic hepatitis C virus infection

Carcinogenic mechanisms of virus-associated lymphoma

The development of lymphoma is a complex multistep process that integrates numerous experimental findings and clinical data that have not yet yielded a definitive explanation. Studies of oncogenic viruses can help to deepen insight into the pathogenesis of lymphoma, and identifying associations between lymphoma and viruses that are established and unidentified should lead to cellular and pharmacologically targeted antiviral strategies for treating malignant lymphoma. This review focuses on the pathogenesis of lymphomas associated with hepatitis B and C, Epstein-Barr, and human immunodeficiency viruses as well as Kaposi sarcoma-associated herpesvirus to clarify the current status of basic information and recent advances in the development of virus-associated lymphomas.

A juggernaut of innate & adaptive immune cells in chronic hepatitis C

Hepatitis C virus (HCV) is a small positive-sense, single-stranded RNA virus, the causal organism for chronic hepatitis. Chronic hepatitis leads to inflammation of liver, causing cirrhosis, fibrosis and steatosis, which may ultimately lead to liver cancer in a few cases. Innate and adaptive immune responses play an important role in the pathogenesis of HCV infection, thus acting as an important component in deciding the fate of the disease. Numerous studies have indicated that the derangement of these immune responses results in the persistence of infection leading to chronic state of the disease. Interactions between virus and host immune system generally result in the elimination of virus, but as the virus evolves with different evading mechanisms, it makes environment favourable for its survival and replication. It has been reported that HCV impairs the immune system by functional modulation of the cells of innate as well as adaptive immune responses, resulting in chronic state of the disease, influencing the response to antiviral therapy in these patients. These defects in the immune system lead to suboptimal immune responses and therefore, impaired effector functions. This review highlights the involvement or association of different immune cells such as natural killer cells, B cells, dendritic cells and T cells in HCV infection and how the virus plays a role in manipulating certain regulatory mechanisms to make these cells dysfunctional for its own persistence and survival.

Anti-rods/rings autoantibody and IMPDH filaments: an update after fifteen years of discovery

Autoantibodies to unknown subcellular rod and ring-shaped structures were first discovered in sera from hepatitis C patients in 2005. Early studies showed a strong association between these anti-rods/rings antibodies (anti-RR) and the standard of care interferon-α plus ribavirin combination therapy (IFN/RBV), suggesting that anti-RR are drug-induced autoantibodies. In the context of hepatitis C, anti-RR have been linked with relapse from or lack of response to IFN/RBV in some patient cohorts. However, examples of anti-RR in other diseases and healthy individuals have also been reported over the years, although anti-RR remains a rare autoantibody response in general. The advent of new direct-acting antiviral drugs for chronic hepatitis C and studies of anti-RR from different parts of the world are also beginning to change the perception of anti-RR. The nucleotide biosynthetic enzyme inosine monophosphate dehydrogenase (IMPDH) has been identified as the major autoantigen recognized by anti-RR. Coincidentally, the assembly of IMPDH into micron-scale rod and ring-shaped structures was discovered around the same time as anti-RR. Knowledge of the fundamental biological properties and cellular functions of these structures, referred to as "IMPDH filaments" by cell biologists, has advanced in parallel to anti-RR antibodies. Recent studies have revealed that IMPDH filament assembly is a mechanism to prevent feedback inhibition of IMPDH and is therefore important for the increased nucleotide production required in hyperproliferating cells, like activated T cells. Fifteen years later, we review the history and current knowledge in both the anti-RR autoantibody and IMPDH filament fields. TAKE-HOME MESSAGE: Anti-rods/rings are recognized as an example of a drug-induced autoantibody in hepatitis C patients treated with interferon and ribavirin, although new studies suggest anti-rods/rings may be detected in other contexts and may depend on unknown environmental or genetic factors in different populations. Recent data suggest that the assembly of IMPDH into rod and ring structures, the targets of anti-rods/rings autoantibody, is a mechanism for hyperproliferating cells, like activated T cells, to maintain increased guanine nucleotide levels to support rapid cell division.

Polyclonal CD5+/CD19+ B1a lymphocytes after allogeneic stem cell transplantation: a potential diagnostic pitfall

In adults, B-lymphocytes comprise approximately 10% of circulating lymphocytes. The majority of peripheral B cells are B2 cells (“Mature” B-cells), which function as part of the humoral adaptive immune system. B1 cells (“Innate-like” B cells) are another sub-class of B lymphocytes, considered as innate immune cells with a characteristic phenotype (CD20+, CD27+, CD43+, CD70-, CD11b+, sIgM++, sIgD+) which can be divided into two subtypes; B1a (CD5+): spontaneously produce broadly reactive natural IgM, and B1b (CD5-): can generate T-cell independent, long-lasting IgM. There is very limited data available, indicating a correlation between allogeneic bone marrow transplantation and an increase in B1a cells. Here we present a case of a 17-year-old female with homozygous sickle cell disease (HbSS disease) who underwent hematopoietic stem cell transplant (HSCT). Approximately seven months post-transplant, she was found to have 16% immature mononuclear cells on complete blood count (CBC)-differential report. A follow-up peripheral blood flow cytometry showed that these cells were polyclonal CD5+/CD20+ B-cells, and comprised 66% of lymphocytes. Further workup and follow up failed to reveal any lymphoproliferative disorders. It is important not to misdiagnose these cells as an atypical CD5+ lymphoproliferative disorder. The presence of B1a cells has not been widely reported in non-neoplastic post-stem cell transplanted patients. This case also adds to and expands our knowledge regarding the presence of increased circulating B1a cells after stem cell transplant in a patient with no history of hematological malignancy.

CD5/CD20 expression on circulating B cells in HCV-related chronic hepatitis and mixed cryoglobulinemia

The role of CD5⁺ B cells in patients with HCV infection and HCV-related disorders, including mixed cryoglobulinemia (MC), has been addressed in previous reports with conflicting results. We established a correlation between CD5/CD20 expression on circulating B lymphocytes, characterizing monoclonal B cell lymphocytosis (MBL), and clinical features in a cohort of 45 patients with chronic HCV hepatitis [without MC: 23 patients (MC- group); with MC: 22 patients (MC+ group)], and 45 HCV-negative healthy subjects as controls. By flow cytometry analysis, three B cells phenotypes were singled out: 1) CD5⁺CD20^dim (CLL-like phenotype); 2) CD5⁺CD20^bright (atypical phenotype); and 3) CD5^-CD20⁺ phenotype. CD5⁺CD20^bright cells were reduced in MC- patients (p=0.049). CD5⁺CD20^dim B cells were significantly higher in group B than in the control group (p=0.003). ROC curve analysis in MC+ patients showed the highest positive likelihood ratio at ≥7.35% (p=0.008) for CLL-like phenotype and at ≤63.6% (p=0.03) for the CD5^-CD20⁺ B cell phenotype. HCV infection was associated with a higher frequency of CLL-like (odds ratio=16, p=0.002) and a lower frequency of atypical (odds ratio: 3.1, p=0.02) and CD5^-CD20⁺ (odds ratio: 11, p=0.01) phenotypes. The association with higher levels of CLL-like phenotype progressively increased from group of MC- patients (odds ratio: 9.3, p=0.04) to the group of MC+ patients (odds ratio: 25.1, p=0.0003). CONCLUSIONS: The occurrence of a CLL-like pattern may allow to identify HCV-infected patients at risk of developing MC and eventually non-Hodgkin lymphoma, who should require a closer surveillance and a longer follow-up.

Association of C-type lectin 18 levels with extrahepatic manifestations in chronic HCV infection

Mixed cryobulinemia (MC) is the most common chronic hepatitis C virus (HCV)-associated extrahepatic manifestation. C-type lectin 18 (CLEC18) is a novel secretory lectin that is abundantly expressed in hepatocytes and peripheral blood cells (PBCs). We investigated the associations between CLEC18 expression during HCV infection and the presence of extrahepatic manifestations. A total of 41 rheumatic patients with HCV infection (including 28 patients with MC syndrome), 45 rheumatic patients without infection, and 14 healthy subjects were enrolled. The CLEC18 levels in PBCs and serum were determined by using flow cytometry and enzyme-linked immunosorbent assay, respectively. Significantly higher CLEC18 levels were observed in patients with HCV infection (P < 0.001) and were positively correlated with HCV viral loads (γ = 0.56, P < 0.05). Among patients with HCV infection, significantly increased CLEC18 levels were observed in patients with MC syndrome, particularly in those with type II MC (P < 0.05). CLEC18 levels were associated with cryoglobulin and C4 levels (P < 0.05). CLEC18 was significantly associated with HCV infection, particularly in those with HCV-associated MC. CLEC18 levels were also positively correlated with MC disease activity, suggesting its involvement in MC pathogenesis. CLEC18 may be a novel indicator of HCV infection and a potential therapeutic target in rheumatic patients.

The Role of BAFF System Molecules in Host Response to Pathogens

The two ligands B cell-activating factor of the tumor necrosis factor family (BAFF) and a proliferation-inducing ligand (APRIL) and the three receptors BAFF receptor (BAFF-R), transmembrane activator and calcium-modulating cyclophilin ligand interactor (TACI), and B cell maturation antigen (BCMA) are members of the "BAFF system molecules." BAFF system molecules are primarily involved in B cell homeostasis. The relevance of BAFF system molecules in host responses to microbial assaults has been investigated in clinical studies and in mice deficient for each of these molecules. Many microbial products modulate the expression of these molecules. Data from clinical studies suggest a correlation between increased expression levels of BAFF system molecules and elevated B cell responses. Depending on the pathogen, heightened B cell responses may strengthen the host response or promote susceptibility. Whereas pathogen-mediated increases in the expression levels of the ligands and/or the receptors appear to promote microbial clearance, certain pathogens have evolved to ablate B cell responses by suppressing the expression of TACI and/or BAFF-R on B cells. Other than its well-established role in B cell responses, the TACI-mediated activation of macrophages is also implicated in resistance to intracellular pathogens. An improved understanding of the role that BAFF system molecules play in infection may assist in devising novel strategies for vaccine development.

Vasculitic syndromes in hepatitis C virus: A review

Vasculitis is a remarkable presentation of the extrahepatic manifestations of HCV. According to the presence or absence of cryoglobulins it is subdivided into two main types: cryoglobulinemic vasculitis and non cryoglobulinemic vasculitis based on the attribution of vasculitis to serum cryoglobulins as a pathogenic factor. The attribution of cryoglobulinemia to HCV represents a success story in the history of immunology, microbiology, and clinical medicine. HCV can bind to and invade lymphocytes, consequently triggering an immune response through different mechanisms. The epidemiology of the disease is well described and the clinical picture describes cutaneous, pulmonary, musculoskeletal, neurological, renal, endocrine, gastrointestinal, hepatic and cardiovascular manifestations. It may also be associated with sicca symptoms, an increased risk of lymphoma and serious catastrophic events. The pathology is well characterized. A classification criteria of the syndrome that was validated in 2014 is discussed. Management of CV is decided according to the presence and severity of its clinical presentation. It is divided into asymptomatic, mild, moderate, severe and life threatening disease. Recently introduced direct antiviral agents are proving safe and effective in the management of cryoglobulinemic vasculitis, and it is advocated that the two types of vasculitis be given prioritization in the Egyptian mass campaign to eradicate HCV.

Pre-stimulation of CD81 expression by resting B cells increases proliferation following EBV infection, but the overexpression of CD81 induces the apoptosis of EBV-transformed B cells

Hepatitis C virus (HCV) E2 protein binds to CD81, which is a component of the B cell co-stimulatory complex. The E2-CD81 interaction leads to B cell proliferation, protein tyrosine phosphorylation and to the hypermutation of immunoglobulin genes. Epidemiological studies have reported a high prevalence of B cell non-Hodgkin lymphoma (NHL) in HCV-positive patients, suggesting a potential association between HCV and Epstein-Barr virus (EBV) in the genesis of B lymphocyte proliferative disorders. In the present study, in order to investigate the association between EBV and HCV in B cells, we created an in vitro EBV-induced B cell transformation model. CD81 was gradually overexpressed during transformation by EBV. B cells isolated from HCV-positive patients grew more rapidly and clumped together earlier than B cells isolated from healthy donors following EBV infection. Pre-stimulation of CD81 expressed by resting B cells with anti-CD81 monoclonal antibody (mAb) or HCV E2 accelerated the generation of lymphoblastoid cell lines (LCLs) by EBV infection. These cells proliferated prominently through the early expression of interleukin-10 and intracellular latent membrane protein (LMP)-l. By contrast, the overexpression of CD81 on EBV-transformed B cells by anti-CD81 mAb or HCV E2 protein induced apoptosis through reactive oxygen species (ROS)-mediated mitochondrial dysfunction. These results suggest that the engagement of CD81 expressed by B cells has differential effects on B cell fate (proliferation or apoptosis) according to EBV infection and the expression level of CD81.

Virus-driven autoimmunity and lymphoproliferation: the example of HCV infection

HCV chronic infection is characterized by possible development of both hepatic and extrahepatic manifestations. The infection by this both hepatotropic and lymphotropic virus is responsible for polyoligoclonal B-lymphocyte expansion, leading to several immune-mediated disorders. Mixed cryoglobulinemia syndrome that in some cases may evolve to frank B-cell non-Hodgkin's lymphoma is the prototype of HCV-driven autoimmune and lymphoproliferative disorders. The HCV oncogenic potential has been suggested by several clinicoepidemiological and laboratory studies; it includes hepatocellular carcinoma, B-cell non-Hodgkin's lymphoma and papillary thyroid cancer. The definition HCV syndrome refers to the complex of HCV-driven diseases; these latter are characterized by heterogeneous geographical distribution, suggesting a role of other important genetic and/or environmental cofactors. The natural history of HCV syndrome is the result of a multifactorial and multistep pathogenetic process, which may evolve from mild manifestations to systemic autoimmune disorders, and less frequently to malignant neoplasias. The present updated review analyzes the clinical and pathogenetic aspects of the main HCV-associated diseases.

CD100 up-regulation induced by interferon-α on B cells is related to hepatitis C virus infection

Objectives

CD100, also known as Sema4D, is a member of the semaphorin family and has important regulatory functions that promote immune cell activation and responses. The role of CD100 expression on B cells in immune regulation during chronic hepatitis C virus (HCV) infection remains unclear.

Materials and Methods

We longitudinally investigated the altered expression of CD100, its receptor CD72, and other activation markers CD69 and CD86 on B cells in 20 chronic HCV-infected patients before and after treatment with pegylated interferon-alpha (Peg-IFN-α) and ribavirin (RBV) by flow cytometry.

Results

The frequency of CD5⁺ B cells as well as the expression levels of CD100, CD69 and CD86 was significantly increased in chronic HCV patients and returned to normal in patients with sustained virological response after discontinuation of IFN-α/RBV therapy. Upon IFN-α treatment, CD100 expression on B cells and the two subsets was further up-regulated in patients who achieved early virological response, and this was confirmed by in vitro experiments. Moreover, the increased CD100 expression via IFN-α was inversely correlated with the decline of the HCV-RNA titer during early-phase treatment.

Conclusions

Peripheral B cells show an activated phenotype during chronic HCV infection. Moreover, IFN-α therapy facilitates the reversion of disrupted B cell homeostasis, and up-regulated expression of CD100 may be indirectly related to HCV clearance.

Antiviral treatment improves disrupted peripheral B lymphocyte homeostasis in chronic hepatitis B virus-infected patients

Disruption of peripheral blood B-cell homeostasis and variation of surface receptors occur with certain infections and autoimmune diseases. However, the impact of antiviral therapy on B-cell alteration during chronic hepatitis B (CHB) infection remains unclear. Our study aims to document the effects of B-cell alteration in CHB patients treated with tenofovir or adefovir. A total of 21 CHB patients and 10 healthy donors were recruited into the study. We identified B-cell subsets by flow cytometry and observed changes in the B-cell repertoire of CHB patients upon tenofovir or adefovir antiviral treatment. The total and percent of B cells and CD5 + B-cell subsets were significantly increased in CHB patients compared to healthy donors. Total and percent of CD5 + B cells gradually decreased following the diminution of the HBV DNA load after tenofovir and adefovir treatment. Upon tenofovir treatment, the percent of memory CD27 + B cells was increased but the absolute number declined, whereas naïve CD27- B cells declined in both percent and absolute number. In the adefovir treatment group, neither naïve nor memory B cells were altered by the treatment. Furthermore, CHB patients displayed higher levels of activation markers (CD69 and CD24) and trended towards restored B-cell homeostasis after antiviral treatment. In conclusion, disrupted B-cell homeostasis is an important feature of CHB patients and is partially restored after control of viral replication by antiviral treatment. B-cell antiviral immunity is improved by restoring B-cell homeostasis and activation.

Hepatitis C-associated B-cell non-Hodgkin lymphomas. Epidemiology, molecular signature and clinical management

There is ample epidemiologic evidence for an association of chronic hepatitis C virus (HCV) infection with B-cell non-Hodgkin lymphoma (B-NHL). B-NHL subtypes most frequently associated with HCV are marginal zone lymphoma and diffuse large B-cell lymphoma. The most convincing evidence for a causal relationship between HCV infection and lymphoma development is the observation of B-NHL regression after HCV eradication by antiviral therapy (AVT). In fact, for indolent HCV-associated B-NHL, first-line AVT instead of standard immune-chemotherapy might be considered. Molecular mechanisms of HCV-NHL development are still poorly understood. Three general theories have emerged to understand the HCV-induced lymphomagenesis: (1) continuous external stimulation of lymphocyte receptors by viral antigens and consecutive proliferation; (2) HCV replication in B cells with oncogenic effect mediated by intracellular viral proteins; (3) permanent B-cell damage, e.g., mutation of tumor suppressor genes, caused by a transiently intracellular virus ("hit and run" theory). This review systematically summarizes the data on epidemiology, interventional studies, and molecular mechanisms of HCV-associated B-NHL.

Early-stage splenic diffuse large B-cell lymphoma is highly associated with hepatitis C virus infection

Splenic marginal zone lymphoma (SMZL) and splenic diffuse large B-cell lymphoma (DLBCL) are the most common types of lymphomas involving the spleen. Geographic variation in hepatitis C virus (HCV) seroprevalence is characteristic of splenic lymphomas. In Italy, HCV seroprevalence was higher in patients with SMZL and splenic DLBCL than in patients with all types of lymphoma. In Japan, HCV seroprevalence was higher in patients with splenic DLBCL than in patients with all types of lymphoma; however, HCV seroprevalence in patients with SMZL was similar to that in patients with all types of lymphoma. In this study, clinicopathological data of 74 splenic lymphoma cases between 1988 and 2011 collected from the Department of Pathology at National Taiwan University Hospital were analyzed. Serology for HCV infection was available for 41 cases. Splenic DLBCL and SMZL accounted for 36% (n = 27) and 42% (n = 31) of splenic lymphomas, respectively. Microscopically, most cases of DLBCL (26/27) presented with circumscribed tumor and most cases of SMZL (28/31) presented with white pulp expansion. HCV seroprevalence in patients with DLBCL and SMZL was 44% and 10%, respectively (7/16 vs. 2/20, p = 0.020). The pattern identified in this study is closer to that in Japan than in Italy. HCV seroprevalence in patients with early-stage (I/II) and late-stage (III/IV) DLBCL was 100% and 10%, respectively (6/6 vs. 1/10, p < 0.001). Early-stage DLBCL is clinically considered a form of primary splenic lymphoma rather than a systemic lymphoma with splenic involvement. High HCV seroprevalence in patients with early-stage DLBCL suggests a role of HCV in the pathogenesis of primary DLBCL.

Hepatitis C virus entry: role of host and viral factors

Hepatitis C virus (HCV) has been considered to be a significant risk factor in developing liver associated diseases including hepatocellular carcinoma all over the world. HCV is an enveloped positive strand virus comprising a complex between genomic RNA and viral envelope glycoproteins (E1 and E2), which are anchored within host derived double-layered lipid membrane surrounding the nucleocapsid composed of several copies of core protein. HCV cell entry is the first step in infection and viral replication into host cells mainly hepatocytes. HCV cell entry is a complex process involving both the viral (envelope glycoproteins E1/E2) and host factors (cellular receptors and associated factors i.e. CD81, SR-BI, LDL-R, CLDN1, Occludin, DC-SIGN, L-SIGN and Glycosaminoglycans). Besides these the expression of certain other conditions such as polarization and EWI-2 expression inhibits the viral cell entry. Exploring the mechanism of HCV entry will help to better understand the viral life cycle and possible therapeutic targets against HCV infection including viral and host factors involved in this process. New strategies such as RNAi represents a new option for targeting the host or viral factors for prevention and therapeutic against HCV infection. In the current review we try to summarize the current knowledge about mechanism and interaction of cellular and viral factors involved in HCV cell entry and its implication as therapeutic target to inhibit HCV infection.

Early lesions in lymphoid neoplasia: Conclusions based on the Workshop of the XV. Meeting of the European Association of Hematopathology and the Society of Hematopathology, in Uppsala, Sweden

The increasing use of immunophenotypic and molecular techniques on lymphoid tissue samples without obvious involvement by malignant lymphoma has resulted in the increased detection of "early" lymphoid proliferations, which show some, but not all the criteria necessary for a diagnosis of malignant lymphoma. In most instances, these are incidental findings in asymptomatic individuals, and their biological behaviour is uncertain. In order to better characterize these premalignant conditions and to establish diagnostic criteria, a joint workshop of the European Association for Haematopathology and the Society of Hematopathology was held in Uppsala, Sweden, in September 2010. The panel reviewed and discussed more than 130 submitted cases and reached consensus diagnoses. Cases representing the nodal equivalent of monoclonal B-cell lymphocytosis (MBL) were discussed, as well as the "in situ" counterparts of follicular lymphoma (FL) and mantle cell lymphoma (MCL), topics that also stimulated discussions concerning the best terminology for these lesions. The workshop also addressed the borderland between reactive hyperplasia, and clonal proliferations such as pediatric marginal zone lymphoma and pediatric FL, which may have very limited capacity for progression. Virus-driven lymphoproliferations in the grey zone between reactive lesions and manifest malignant lymphoma were covered. Finally, early manifestations of T-cell lymphoma, both nodal and extranodal, and their mimics were addressed. This workshop report summarizes the most important conclusions concerning diagnostic features, as well as proposals for terminology and classification of early lymphoproliferations and tries to give some practical guidelines for diagnosis and reporting.

Hepatitis C and non-Hodgkin lymphoma: the clinical perspective

Hepatitis C virus (HCV) is a commonly transmitted infection that has both hepatic and extrahepatic repercussions. These range from the inflammatory to the oncologic with an undisputed link to hepatitis, liver cirrhosis, and hepatocellular carcinoma. Its role in the development of B cell non-Hodgkin lymphoma (B-NHL) is becoming better understood, leading to opportunities for research, therapy, and even prevention. Research in the field has progressed significantly over the last decade, with the number of patients diagnosed with HCV and B-NHL rising incrementally. It is therefore becoming crucial to fully understand the pathobiologic link of HCV in B cell lymphomagenesis and its optimal management in the oncologic setting.

Hepatitis C and autoimmunity: a therapeutic challenge

Hepatitis C virus (HCV) infection causes not only acute and chronic liver disease, but also extrahepatic symptoms. To our knowledge, this is the first case report of a patient who developed simultaneously subacute cutaneous lupus erythematosus and a small CD20+ B-cell clone because of chronic HCV infection and relapse after standard of care therapy (pegylated interferon plus ribavirin). Treatment with rituximab, a chimeric anti-CD20 monoclonal antibody, was successful.

The lymphocyte immunophenotypical pattern in chronic lymphocytic leukemia associated with hepatitis viral infections

BACKGROUND

Chronic lymphoproliferative disorders (CLD) are frequently found in patients with hepatitis viral infections, which can lead to changes in pathogenesis. Hepatitis viruses are hepatotrope viruses, potentially lymphotrope and also potentially oncogenic (hepatocellular carcinoma) viruses. HBV and HCV are involved in autoimmune disorders and in the ethiopathogeny of chronic lymphoproliferative disorders.

AIM

Detection of immunophenotype changes of malignant lymphocytes in CLD--especially CLL--associated with hepatitis viral infections.

MATERIALS AND METHODS

Bone marrow aspirate, peripheral blood samples on EDTA were available for analysis from 58 patients from a follow-up schedule of the Department of Hematology SUUB from March 2008 until June 2009. The patients were diagnosed with chronic lymphoproliferative disorders associated with hepatitis virus B/C/D infections. A group of 28 consecutive unselected patients with CLL who met the diagnostic criteria of the National Cancer Institute-Working Group (NCI NCIWG), and associated hepatitis viral infection (v-CLL) were studied for the expression of several immunophenotypical markers, in comparison to CLL patients without viral infection (control group). Immunophenotyping analysis was performed on a FACS Calibur flowcytometer with a large panel according to EGIL/WHO recommendations. The diagnosis was completed after the histological and immunochemical analysis from tumoral lesions.

RESULTS

Demographics characteristics--male/female ratio 1/2, average age 64 years. Disease type: 90% B-CLD, 5% T-CLD, 5% Hodgkin's disease. The viral infections: 58.53% HCV, 34.41% HBV, 2.43% HBV+HDV, 2.43% HCV+HDV, 2.43% HBV+HCV+HDV. We found in CLL with viral coinfection (v-CLL) cases an elevated expression of B-cell markers--CD19 (Md95/92), CD20 (Md 90/39), CD79b (Md58/31), CD23 (Md67/37). Poor prognosis markers have a higher expression in v-CLL: CD38 (Md49/24), Bcl2 (Md 46/5), cyclin D19 (Md 11/0.5). No change in ZAP-70 expression was observed: Md 59.5/59.1.

DISCUSSIONS

Hepatitis viruses could be involved in the pathogenesis of CLD, but as a trigger for a more aggressive outcome. Higher expression of B-cell markers CD19, CD20 in CLL with viral infection suggests a change to atypical CLL, sustained by elevated expression of known poor prognosis markers bcl-2, cyclin D1 and CD38. Lack of ZAP-70 expression could be explained by a strong correlation with a basic unmutated IgVH status, not related to the viral infection. We found a higher frequency of HCV infection in patients with CLD and especially in CLL patients, which were analyzed extensively for immunophenotypical changes. In the present study, we demonstrated that this CD5+ B cell population with clonal expansion, defining CLL patients, has a different immunophenotype, probably related to the hepatitis viral infection.

A prospective study of T- and B-lymphocyte subpopulations, CD81 expression levels on B cells and regulatory CD4(+) CD25(+) CD127(low/-) FoxP3(+) T cells in patients with chronic HCV infection during pegylated interferon-alpha2a plus ribavirin treatment

Resolution of hepatitis C virus (HCV) infection requires a complex interplay between innate and adaptative immune responses. The role of lymphocyte subpopulations during combined antiviral treatment remains to be defined. This study was conducted to assess the effect of pegylated interferon-alpha2a (pegIFN-α2a) and ribavirin treatment on peripheral blood lymphocytes, mainly on CD81 expression on B cells and CD4(+) CD25(+) CD127(low/-) FoxP3(+) regulatory T cells (Tregs) in patients with chronic HCV infection. Thirty-five patients with chronic HCV infection who started pegIFN-α2a and ribavirin treatment were enrolled. Peripheral blood mononuclear cells (PBMC) were obtained at baseline before treatment (BT), mid-treatment (MT), the end of treatment (ET) and 24weeks post-treatment (PT). During combined antiviral treatment, a significant decrease in the percentage of CD3(+) , CD8(+) , CD3(+) gamma/delta (γδ)(+) , CD19(+) lymphocyte subpopulations and Tregs was observed. There was also a significant increase in the percentage of the CD4(+) lymphocyte subpopulation and in CD81 expression levels on CD19(+) B cells when BT was compared with ET (all P<0.05). Seventeen patients were nonresponders (NR) and 18 had a sustained virological response (SVR). At baseline, NR patients had higher CD81 expression levels on CD19(+) B cells (P=0.017) and a higher Tregs percentage (P=0.025) than SVR patients. Our results suggest that immunomodulation fluctuates during antiviral treatment and that percentage CD81 expression levels on B cells and Tregs might be useful as an immunological prognostic factor for pegIFN-α2a and ribavirin treatment response in chronic HCV infection.

Hepatitis C virus protects human B lymphocytes from Fas-mediated apoptosis via E2-CD81 engagement

HCV infection is often associated with B-cell regulatory control disturbance and delayed appearance of neutralizing antibodies. CD81 is a cellular receptor for HCV and can bind to HCV envelope protein 2 (E2). CD81 also participates to form a B cell costimulatory complex. To investigate whether HCV influences B cell activation and immune function through E2 -CD81 engagement, here, human Burkitt's lymphoma cell line Raji cells and primary human B lymphocytes (PHB) were treated with HCV E2 protein and cell culture produced HCV particles (HCVcc), and then the related cell phenotypes were assayed. The results showed that both E2 and HCVcc triggered phosphorylation of IκBα, enhanced the expression of anti-apoptosis Bcl-2 family proteins, and protected Raji cells and PHB cells from Fas-mediated death. In addition, both E2 protein and HCVcc increased the expression of costimulatory molecules CD80, CD86 and CD81 itself, and decreased the expression of complement receptor CD21. The effects were dependent on E2-CD81 interaction on the cell surface, since CD81-silenced Raji cells did not respond to both treatments; and an E2 mutant that lose the CD81 binding activity, could not trigger the responses of both Raji cells and PHB cells. The effects were not associated with HCV replication in cells, for HCV pseudoparticle (HCVpp) and HCVcc failed to infect Raji cells. Hence, E2-CD81 engagement may contribute to HCV-associated B cell lymphoproliferative disorders and insufficient neutralizing antibody production.

Increased polyclonal CD5+ B1a lymphocytes in a haploidentical stem cell transplant recipient

BACKGROUND

Atypical lymphocyte populations may be seen in the peritransplant setting. In this case report, we describe an unusually high number of CD5+ B-cells (B1a cells) following transplant.

METHODS

B1a cells identified during routine follow-up by immunophenotypic analysis in a middle-aged man who had a haploidentical stem cell transplant for acute myeloid leukemia were compared with a reference set of post-transplant samples.

RESULTS

Increased but polyclonal B1a cells were identified with 100% donor chimerism.

CONCLUSIONS

Our case demonstrates that a high absolute number of B1a cells may be seen post-transplant and should not be confused with an atypical CD5+ lymphoproliferative disorder. Furthermore, the population of polyclonal CD5+ B lymphocytes from the patient's donor is prominent 7 months post-transplant. This suggests that the maintenance of CD5+ B1 cells prior to conversion to adult-type CD5⁻ B2 cells is not hindered by the recipient adult stromal environment.

Prolonged infections associated with antineutrophil cytoplasmic antibodies specific to proteinase 3 and myeloperoxidase: diagnostic and therapeutic challenge

Chronic infections may mimic antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV). We investigated which markers may help in the diagnosis and the prognosis of infections associated with proteinase 3 (PR3) and myeloperoxidase (MPO)-ANCA. In this study (1993-2008)--with an average follow-up of 5.1 years--we compared 66 AAV patients with 17 PR3 and/or MPO-ANCA-positive patients with protracted bacterial (11/17) or viral (6/17) infections. Seven of 17 patients had subacute bacterial endocarditis (SBE), while six of 17 patients had various autoimmune manifestations of chronic hepatitis C virus (HCV) infection. We determined ANCA, antinuclear antibodies, anti-PR3, anti-MPO, anticardiolipin (aCL), antibeta 2 glycoprotein I (beta2-GP I), cryoglobulins, C3, and C4. Patients with infections were younger than AAV patients (p < 0.01). There was no difference in frequency of renal and skin lesions. AAV patients more frequently had pulmonary and nervous system manifestations (p < 0.01). Patients with infections more frequently had dual ANCA (high PR3, low MPO), aCL, anti-beta2-GP I, cryoglobulins, and hypocomplementemia (p < 0.001). Immunosuppressive therapy (IST) was used in five 17 patients who had persistently high ANCA, cryoglobulinemia, and hypocomplementemia. There was no difference in frequency of lethality and renal failure in the two study groups. In patients who are PR3- and/or MPO-ANCA positive, SBE and HCV infection should be excluded. Although similar in renal and skin manifestations in comparison to AAV, only patients with infections developed multiple serological abnormalities. In patients with infections, concomitant presence of ANCA, cryoglobulins, and hypocomplementemia was associated with severe glomerulonephritis. The serological profile should be repeated after specific antimicrobial or surgical therapy, since some cases might require IST.

The 1F7 idiotype is selectively expressed on CD5+ B cells and elevated in chronic hepatitis C virus infection

Antibodies against different chronic viruses, including hepatitis C virus (HCV), express a public cross-reactive idiotype (Id) designated as 1F7. The prominence of this Id may reflect selective engagement of B1 B cells by chronic pathogens. We investigated this by comparing 1F7 Id expression on CD5(+) and CD5(-) B cells, total IgG, total IgM and anti-HCV core antibodies in different HCV exposure settings. By flow cytometry, we observed a selective increase in 1F7 Id(+)CD5(+) B cells in chronic HCV infection. 1F7 Id levels in different immunoglobulin compartments were measured by enzyme-linked immunosorbent assay. 1F7 Id expression was prominent in anti-HCV core antibodies of approximately 90% of 141 HCV-exposed individuals tested. In the Canadian and Armenian study groups, participants who spontaneously cleared HCV infection had lower median 1F7 Id levels on total plasma IgG and anti-HCV core antibodies. Armenian spontaneous clearers, who were younger and more recently infected than their Canadian counterparts, also had had lower median 1F7 Id levels on total plasma IgM. Engagement by HCV of B-cell receptors within, or overlapping with the CD5(+) B1 B-cell repertoire is reflected in the production of 1F7 Id(+) anti-HCV antibodies and expansion of 1F7 Id(+)CD5(+) B cells. Higher 1F7 Id expression levels are associated with chronic infection.

Immune responses in hepatitis C virus infection and mechanisms of hepatitis C virus persistence

Immune responses against hepatitis C virus (HCV) play a crucial role in the pathogenesis of chronic hepatitis C. HCV infection often persists and leads to chronic hepatitis and eventually cirrhosis. Accumulated data suggest that HCV proteins suppress host immune responses through the suppression of functions of immune cells, such as cytotoxic T lymphocytes, natural killer cells, and dendritic cells. They also suppress the type 1 interferon signaling system. The resulting insufficient immune responses against HCV lead to the sustained infection. The appropriate control of immune responses would contribute to the eradication of HCV and the improvement of hepatitis, but there are still many issues to be clarified. This review describes the scientific evidence to support these emerging concepts, and will touch on the implications for improving antiviral therapy.

Clonal expansion of immunoglobulin M+CD27+ B cells in HCV-associated mixed cryoglobulinemia

Hepatitis C virus (HCV) is associated with B-cell lymphoproliferative disorders such as mixed cryoglobulinemia (MC) and B-cell non-Hodgkin lymphoma (B-NHL). The pathogenesis of these disorders remains unclear, and it has been proposed that HCV drives the pro-liferation of B cells. Here we demonstrate that certain HCV(+)MC(+) subjects have clonal expansions of immunoglobulin M (IgM)(+)kappa(+)IgD(low/-)CD21(low)CD27(+) B cells. Using RT-PCR to amplify Ig from these singly sorted cells, we show that these predominantly rheumatoid factor-encoding V(H)1-69/J(H)4 and V(kappa)3-20 gene segment-restricted cells have low to moderate levels of somatic hypermutations. Ig sequence analysis suggests that antigen selection drives the generation of mutated clones. These findings lend further support to the notion that specific antigenic stimulation leads to B-cell proliferation in HCV MC and that chronic B-cell stimulation may set the stage for malignant transformation and the development of B-NHL. The finding that these hypermutated, marginal zone-like IgM(+)CD27(+) B cells are clonally expanded in certain subjects with MC offers insight into mechanisms of HCV-associated MC and B-cell malignancy. This study was registered at www.clinicaltrials.gov as NCT00219999.

The pathophysiology of HCV induced B-cell clonal disorders

Hepatitis C virus (HCV) has been shown in epidemiologic studies to be associated with immune system disorders. Primarily disorders that stem from B-cell regulatory control disturbance, such as mixed cryoglobulinemia (MC) and non-Hodgkin's lymphoma (NHL). The causative role of HCV in these disorders is supported by the response to anti-viral treatment. The understanding of the pathophysiological process leading from HCV infection to B-cell clonal expansion has improved significantly. Data supports an antigen-driven indirect stimulation of clonal expansion model, leading from oligoclonal to monoclonal expansion and in some instances to frank malignancy. HCV-E2 antigen has been suggested as a candidate antigen as well as NS3. Binding of the B-cell receptor by viral antigens coupled with direct binding of CD-81 by HCV-E2 has been shown to provide a strong proliferative signal. Additional regulatory elements are also affected in HCV-related B-cell clonal expansion, including the Fas and BLyS signaling mechanisms. Finally, genetic events such as bcl-2 rearrangement may also be involved in clonal expansion. In this review, evidence linking HCV with MC and NHL, as well as known events in the pathophysiological process are described.

Novel serum biomarker candidates for liver fibrosis in hepatitis C patients

BACKGROUND

Liver biopsy is currently the gold standard for assessing liver fibrosis, and no reliable noninvasive diagnostic approach is available. Therefore a suitable serologic biomarker of liver fibrosis is urgently needed.

METHODS

We used a proteomics method based on 2-dimensional gel electrophoresis to identify potential fibrosis biomarkers. Serum samples from patients with varying degrees of hepatic scarring induced by infection with the hepatitis C virus (HCV) were analyzed and compared with serum from healthy controls.

RESULTS

We observed the most prominent differences when we compared serum samples from cirrhotic patients with healthy control serum. Inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4) fragments, alpha1 antichymotrypsin, apolipoprotein L1 (Apo L1), prealbumin, albumin, paraoxonase/arylesterase 1, and zinc-alpha2-glycoprotein were decreased in cirrhotic serum, whereas CD5 antigen-like protein (CD5L) and beta2 glycoprotein I (beta2GPI) were increased. In general, alpha2 macroglobulin (a2M) and immunoglobulin components increased with hepatic fibrosis, whereas haptoglobin and complement components (C3, C4, and factor H-related protein 1) decreased. Novel proteins associated with HCV-induced fibrosis included ITIH4 fragments, complement factor H-related protein 1, CD5L, Apo L1, beta2GPI, and thioester-cleaved products of a2M.

CONCLUSIONS

Assessment of hepatic scarring may be performed with a combination of these novel fibrosis biomarkers, thus eliminating the need for liver biopsy. Further evaluation of these candidate markers needs to be performed in larger patient populations. Diagnosis of fibrosis during early stages will allow early treatment, thereby preventing fibrosis progression.

Polyclonal B cell activation in infections: infectious agents' devilry or defense mechanism of the host?

Polyclonal B cell activation is not a peculiar characteristic to a particular infection, as many viruses, bacteria, and parasites induce a strong polyclonal B cell response resulting in hyper-gamma-globulinemia. Here, we discuss the different roles proposed for polyclonal B cell activation, which can be crucial for early host defense against rapidly dividing microorganisms by contributing antibodies specific for a spectrum of conserved structures present in the pathogens. In addition, polyclonal B cell activation can be responsible for maintenance of memory B cell responses because of the continuous, unrestricted stimulation of memory B cells whose antibody production may be sustained in the absence of the antigens binding-specific BCR. Conversely, polyclonal activation can be triggered by microorganisms to avoid the host-specific, immune response by activating B cell clones, which produce nonmicroorganism-specific antibodies. Finally, some reports suggest a deleterious role for polyclonal activation, arguing that it could potentially turn on anti-self-responses and lead to autoimmune manifestations during chronic infections.

Altered expression of the tetraspanin CD81 on B and T lymphocytes during HIV-1 infection

CD81 is a member of the tetraspan superfamily and plays a role in immune responses and in hepatitis C virus (HCV) pathogenesis. We analysed CD81 cell surface and mRNA expression in different lymphocytic subpopulations in human immunodeficiency virus (HIV)-1, HCV and dually infected subjects. CD81 cell surface expression was evaluated with fluorescence activated cell sorter (FACS) analysis; mRNA quantification was performed with semiquantitative polymerase chain reaction (PCR). CD81 cell surface expression on CD4(+) T lymphocytes was significantly different by analysis of variance (anova) test (P < 0.001), with reduced expression in HIV-1(+) patients. In B lymphocytes, higher cell surface expression was present in HIV-1, in HCV and in dually infected subjects compared to healthy controls. CD81 expression on B lymphocytes showed a positive correlation with plasma HIV-RNA. CD81 mRNA levels in B lymphocytes were significantly higher in HIV-1(+) patients compared to healthy controls. The potential consequence of the down-regulation of CD81 in CD4(+) cells during HIV-1 infection in conjunction with diverted CD28, CD4 and CD3 expression is the disruption of T cell function. Increased CD81 expression on B lymphocytes might explain the higher prevalence of lymphoproliferative disorders in HIV-1 and HCV infection. Up-regulation of CD81 mRNA on CD4(+) T cells indicates that down-regulation of CD81 occurs at the post-transcriptional/translational level.

Elevated serum B-Lymphocyte activating factor (BAFF) in chronic hepatitis C virus infection: association with autoimmunity

In this study we aimed to determine whether serum B-lymphocyte activating factor (BAFF) level is increased in patients with chronic hepatitis C virus (HCV) infection, and to assess its association with HCV-related autoimmunity. Sixty-five patients with chronic HCV infection were compared with two disease control groups [57 patients with systemic lupus erythematosus (SLE) and 15 with chronic hepatitis B virus (HBV) infection] and a healthy control group of 35 individuals. A special attention was given to HCV-related arthralgia and or vasculitis. Serum BAFF was assessed in all studied individuals, whereas rheumatoid factor (RF), anti-cardiolipin antibodies (aCL), and cryoglobulins were determined in HCV and HBV infected patients, and anti-dsDNA antibodies and aCL were assessed in patients with SLE. Mean serum BAFF was increased in patients with HCV infection and SLE (2.4+/-0.8 ng/ml and 3.1+/-1.34 ng/ml respectively) compared to 1.1+/-0.14 ng/ml in patients with HBV; and to 1.1+/-0.27 in healthy controls (all, p<0.0001). The elevation in serum BAFF was associated with HCV-related arthralgia and or vasculitis (p<0.0001), and with the presence of aCL and of cryoglobulins. HBV patients lacked features suggestive of autoimmunity. In SLE patients, elevated serum BAFF was in association with the presence of anti-dsDNA (p=0.002). As in other autoimmune diseases, increased serum BAFF was also found in patients with chronic HCV infection. Elevated serum BAFF levels were associated with clinical and laboratory features of autoimmunity, suggesting that BAFF may play a role in HCV-related autoimmunity.

Hepatitis C virus drives the unconstrained monoclonal expansion of VH1-69-expressing memory B cells in type II cryoglobulinemia: a model of infection-driven lymphomagenesis

Chronic hepatitis C virus infection causes B cell lymphoproliferative disorders that include type II mixed cryoglobulinemia and lymphoma. This virus drives the monoclonal expansion and, occasionally, the malignant transformation of B cells producing a polyreactive natural Ab commonly encoded by the V(H)1-69 variable gene. Owing to their property of producing natural Ab, these cells are reminiscent of murine B-1 and marginal zone B cells. We used anti-Id Abs to track the stages of differentiation and clonal expansion of V(H)1-69(+) cells in patients with type II mixed cryoglobulinemia. By immunophenotyping and cell size analysis, we could define three discrete stages of differentiation of V(H)1-69(+) B cells: naive (small, IgM(high)IgD(high)CD38(+)CD27(-)CD21(high)CD95(-)CD5(-)), "early memory" (medium-sized, IgM(high)IgD(low)CD38(-)CD27(+)CD21(low)CD95(+)CD5(+)), and "late memory" (large-sized, IgM(low)IgD(low-neg)CD38(-)CD27(low)CD21(low-neg)CD5(-)CD95(-)). The B cells expanded in cryoglobulinemia patients have a "memory" phenotype; this fact, together with the evidence for intraclonal variation, suggests that antigenic stimulation by hepatitis C virus causes the unconstrained expansion of activated V(H)1-69(+) B cells. In some cases, these cells replace the entire pool of circulating B cells, although the absolute B cell number remains within normal limits. Absolute monoclonal V(H)1-69(+) B lymphocytosis was seen in three patients with cryoglobulinemia and splenic lymphoma; in two of these patients, expanded cells carried trisomy 3q. The data presented here indicate that the hepatitis C virus-driven clonal expansion of memory B cells producing a V(H)1-69(+) natural Ab escapes control mechanisms and subverts B cell homeostasis. Genetic alterations may provide a further growth advantage leading to an overt lymphoproliferative disorder.

The CD5+ B-cell

In the last two decades, many efforts have been made to better understand the biology of B-lymphoproliferative disorders through the knowledge of physiology and function of the postulated normal counterpart. The follicular mantle B-cells express a typical CD23+ IgM+ IgD+ phenotype and surround the germinal center area in secondary lymphoid organs. CD5+ B-cells with FM phenotype can be isolated from different sources and all share similar morphologic, phenotypic and functional features (small cells, scanty nucleus/cytoplasm ratio, unmutated VH genes, response to polyclonal activators but not to T independent antigens, production of "natural" antibodies). While the CD5+ B-cells predominate in fetal life, their number decreases with age. However, the CD5+ B-cells have been demonstrated to increase again in elderly both in man and mouse. This finding may explain the incidence of B-CLL and of MCL that are believed to represent the malignant transformation of the normal CD5+ B-cells, among elderly and middle aged individuals, respectively.

Enhanced apoptosis of peripheral CD5-negative B lymphocytes from chronically hepatitis C virus-infected patients: reversal after antiviral treatment

Whereas enhanced peripheral T-cell apoptosis and its association with autoimmunity have recently been reported, the apoptotic status of peripheral B cells in chronic hepatitis C virus (HCV) infection remains ambiguous. We therefore sought to investigate the sensitivity of peripheral B cells to apoptosis and to assess the possible benefits of antiviral treatment in mitigating these effects. Spontaneous apoptosis, the extent of apoptosis rescue, and NF-kappaB expression in peripheral B cells were studied in patients with chronic HCV infections (group 1), in sustained responders after antiviral treatment (group 2), and in healthy controls (group 3). For group 1, spontaneous B-cell apoptosis was increased (26% +/- 4.6%) and apoptosis rescue was altered (39%) compared to group 3 (18% +/- 5% and 50%, respectively; P = 0.001). In contrast, apoptosis and apoptosis rescue were similar for groups 2 and 3. Enhanced B-cell apoptosis was associated with decreased NF-kappaB expression and was found only in CD5-negative (CD5(neg)) B cells, whereas CD5(pos) cells were apoptosis resistant. Chronic HCV infection is associated with enhanced peripheral B-cell apoptosis and decreased apoptosis rescue. Successful antiviral treatment reverses these abnormalities to the levels seen in healthy individuals. The relative resistance of the CD5(pos) B-cell subpopulation to apoptosis may play a role in HCV-related autoimmunity and lymphoproliferation.

Mutations in the putative HCV-E2 CD81 binding regions and correlation with cell surface CD81 expression

The hepatitis C virus (HCV) envelope (E)2 protein interacts with the cellular receptor CD81 leading to modulation of B and T cell function. Recently, a higher binding affinity of subtype 1a in comparison with 1b derived E2 proteins for CD81 in vitro was described. The importance of mutations within the putative CD81 binding regions of different HCV geno-/subtypes in correlation with CD81 expression is unknown. In the present study, CD81 expression on blood lymphocytes of patients with chronic hepatitis C infected with different HCV geno-/subtypes were analysed by fluorescence activated cell sorter analyses. In addition, the putative CD81 binding regions on the E2 gene comprising the hypervariable region (HVR)2 were analysed by direct sequencing. CD81 expression on CD8(+) T-lymphocytes from patients infected with subtype 1a (n = 6) was significantly higher in comparison with subtype 1b (n = 12) and 3 (n = 5) infected patients before and during antiviral therapy (P = 0.006; P = 0.021, respectively). Sequencing of the putative CD81 binding regions in the E2 protein comprising the HVR2 (codon 474-495 and 522-552 according to the HCV-1a prototype HCV-H) showed a highly conserved motif within HVR2 for subtype 1a isolates and an overall low number of mutations within the putative CD81 binding regions, whereas numerous mutations were detected for subtype 1b isolates (12.0 vs 23.6%). HCV-3 isolates showed an intermediate number of mutations within the putative binding sites (19.2%; P = 0.022). In conclusion, the highly conserved sequence within HVR2 and putative CD81 binding sites of subtype 1a isolates previously associated with a high CD81 binding affinity in vitro is correlated with high CD81 expression on CD8(+) T-lymphocytes in vivo.

Helicobacter pylori and Malignant Lymphoma in Spain

Helicobacter pylori has been associated with gastric adenocarcinoma and gastric lymphoma. We report on the systematic evaluation of serologic detection of H. pylori in a lymphoma case-control study. Methods: Cases (N = 536) were consecutive patients newly diagnosed with a lymphoid malignancy between 1998 and 2002 in four centers in Spain. Lymphomas were diagnosed and classified using the WHO Classification. Controls (N = 603) were hospitalized patients frequency-matched to the cases by 5-year age group, sex, and study center. Severe immunocompromised patients were excluded as controls. Patients underwent a personal interview and blood sampling. H. pylori infection was evaluated by the presence of IgG antibodies using the Premier enzyme immunoassay kit (Meridian Diagnostics Inc., Cincinnati, OH). Logistic regression analysis was used to estimate the odds ratios and 95% confidence intervals (OR, 95% CI) for lymphoma categories. Results: Anti-H. pylori antibodies were detected in 68.5% of the cases and 71.3% of the controls (P = 0.29) H. pylori was associated with a 3-fold excess risk of splenic marginal B-cell lymphoma (OR = 3.97, 95% CI = 0.92-17.16). H. pylori was not associated with an overall increased risk of extranodal lymphomas (OR = 0.73, 95% CI = 0.44-1.22) but when specific sites were explored, the four mucosa-associated lymphoid tissue and the six diffuse large B-cell lymphomas primary localized in the stomach were all H. pylori seropositive. Conclusion: Persistent infection with H. pylori may be implicated in the development of lymphomas of the gastric mucosa and of the spleen. These results could have clinical implications in the management of splenic marginal zone lymphomas.

Antiviral treatment down-regulates peripheral B-cell CD81 expression and CD5 expansion in chronic hepatitis C virus infection

Hepatitis C virus (HCV) infection is associated with immune-mediated abnormalities and B-cell lymphoproliferation. Recently, CD81 was identified as an HCV receptor on B lymphocytes, providing a mechanism by which B cells are infected and activated by the virus. It has recently been shown that peripheral B-cell CD81 overexpression and CD5(+) subpopulation expansion correlate with HCV viral load and are associated with the development of HCV-related autoimmunity. In the present study, we assessed the effects of combination antiviral therapy (alfa interferon and ribavirin) on peripheral B-cell CD81 expression and CD5 expansion and the presence of autoimmune markers. Peripheral B-cell CD5 expression and the mean fluorescence intensity of CD81 were assessed by flow cytometry before and after treatment in 15 HCV-infected patients, in 10 untreated patients, and in 25 healthy controls. A significant posttreatment decrease in peripheral B-cell CD81 expression and disappearance of CD5(+) B-cell expansion were observed in all nine patients in whom a complete and sustained virological response was achieved (P < 0.01) (comparable to those for healthy controls). The decrease in CD81 overexpression and CD5 expansion in these patients was associated with a decrease and/or disappearance of autoimmune markers. In contrast, in nonresponders overexpression of CD81 and expansion of the CD5(+) B-cell subpopulation were not significantly changed and were comparable to those for untreated patients. In conclusion, antiviral therapy down-regulates peripheral B-cell CD81 expression and the CD5(+) population, either directly or by its effect on HCV RNA load. The overexpression of CD81 and the expansion of the population of CD5(+) peripheral B cells in HCV-infected patients may possibly play a role in the development of HCV-associated autoimmunity and lymphoproliferation.

Effect of antiviral treatment in patients with chronic HCV infection and t(14;18) translocation

Hepatitis C virus (HCV) may be associated with the mixed cryoglobulinemia syndrome and other B-cell lymphoproliferative disorders (LPDs). The t(14;18) translocation may play a pathogenetic role. Limited data are available regarding the effects of antiviral therapy on rearranged B-cell clones. We evaluated the effects of interferon and ribavirin on serum, B-lymphocyte HCV RNA, and t(14; 18) in 30 HCV+, t(14;18)+ patients without either mixed cryoglobulinemia syndrome or other LPDs. The t(14;18) translocation was analyzed by both bcl-2/JH polymerase chain reaction and bcl-2/JH junction sequencing in peripheral blood mononuclear cells in all patients. Fifteen untreated patients with comparable characteristics served as controls. Throughout the study, the presence or absence of both t(14;18) and HCV RNA sequences were, in most cases, associated in the same cell samples. At the end of treatment, t(14;18) was no longer detected in 15 patients (50%) with complete or partial virologic response, whereas it was persistently detected in nonresponders (P <.05), as well as in 14 of 15 control patients. In 4 responder patients, t(14;18) and HCV RNA sequences were no longer detected in blood cells after treatment, but were again detected after viral relapse; the same B-cell clones were involved in the pretreatment and posttreatment periods. In conclusion, this study suggests that antiviral therapy may induce regression of t(14;18)-bearing B-cell clones in HCV+ patients and that this phenomenon may be related, at least in part, to the antiviral effect of therapy. This in turn suggests that antiviral treatment may help prevent or treat HCV-related LPDs.

Expansion of innate CD5pos B cells expressing high levels of CD81 in hepatitis C virus infected liver

BACKGROUND/AIMS

Association of hepatitis C virus (HCV) with increased autoantibodies, mixed cryoglobulinaemia, non-Hodgkin's B-cell lymphoma and increased peripheral innate (CD5(pos)) B cells suggests a role for B-lymphocytes in the pathogenesis of HCV-infection.

METHODS

Flow cytometry was used to estimate CD5(pos) B cell levels and CD81 co-expression in chronic HCV infection. Viral load was assessed using PCR.

RESULTS

We demonstrate expansion of innate B cells in HCV-infected liver from patients with fibrosis score less than stage II (39%, % of total B cells, P=0.002) and end stage HCV cirrhosis (20%, P<0.05) compared with normal liver (8%). Expression of CD81, a signal transducing molecule and putative HCV receptor, was significantly increased on peripheral blood CD5(pos) B cells compared with conventional B cells (P=0.0001). Higher levels of CD81 on CD5(pos) B cells were more dramatic in the liver of HCV-infected individuals. However, no significant difference was observed in the viral load of CD5(pos)CD81(High) B cells and CD5(neg)CD81(Low) B cells.

CONCLUSIONS

Increased expression of CD81 on innate B cells, a population that is expanded in the livers and peripheral blood of chronic HCV-infected patients, suggests a role in viral specific activation and clonal proliferation in chronic HCV infection.

Accumulation of B lymphocytes with a naive, resting phenotype in a subset of hepatitis C patients

Chronic infection with hepatitis C virus (HCV) is associated with disturbances of B lymphocyte activation and function: autoantibody production, mixed cryoglobulinemia, and B cell lymphomas. It has been proposed that these abnormalities reflect chronic antigenic stimulation or aberrant signaling through the B cell coreceptor, the latter mediated by binding of the HCV E2 glycoprotein to CD81. To test this hypothesis, we measured expression of activation and differentiation markers on peripheral blood B cells from patients with chronic HCV infection. Thirty-six HCV patients with and without mixed cryoglobulinemia were compared with 18 healthy control volunteers and 17 sustained virologic responders who had cleared HCV infection. Ten of the 36 HCV patient samples showed increased B cell frequencies; B cell frequency was higher in patients with more severe hepatic fibrosis. However, these samples lacked evidence of Ag-driven activation or proliferation. The expanded cells were low in the activation markers CD25, CD69, CD71, CD80, and CD86. Proliferation of circulating B cells was unchanged in HCV patients. These cells did not express the differentiation marker CD27, suggesting that they were not enriched in memory B cells. Furthermore, the expanded B cells expressed both IgD and IgM, suggesting that they were antigenically naive. Together, these results indicate that B cell expansion in the peripheral blood of HCV patients is not associated with Ag-mediated activation and differentiation. Instead, factors other than antigenic stimulation may promote the accumulation of peripheral blood B cells with a naive phenotype in a subset of HCV patients.