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Contains fulltext : 286832.pdf (Publisher’s version ) (Open Access) BACKGROUND: Direct evaluation of vascular inflammation in patients with COVID-19 would facilitate more efficient trials of new treatments and identify patients at risk of long-term complications who might respond to treatment. We aimed to develop a novel artificial intelligence (AI)-assisted image analysis platform that quantifies cytokine-driven vascular inflammation from routine CT angiograms, and sought to validate its prognostic value in COVID-19. METHODS: For this prospective outcomes validation study, we developed a radiotranscriptomic platform that uses RNA sequencing data from human internal mammary artery biopsies to develop novel radiomic signatures of vascular inflammation from CT angiography images. We then used this platform to train a radiotranscriptomic signature (C19-RS), derived from the perivascular space around the aorta and the internal mammary artery, to best describe cytokine-driven vascular inflammation. The prognostic value of C19-RS was validated externally in 435 patients (331 from study arm 3 and 104 from study arm 4) admitted to hospital with or without COVID-19, undergoing clinically indicated pulmonary CT angiography, in three UK National Health Service (NHS) trusts (Oxford, Leicester, and Bath). We evaluated the diagnostic and prognostic value of C19-RS for death in hospital due to COVID-19, did sensitivity analyses based on dexamethasone treatment, and investigated the correlation of C19-RS with systemic transcriptomic changes. FINDINGS: Patients with COVID-19 had higher C19-RS than those without (adjusted odds ratio [OR] 2·97 [95% CI 1·43-6·27], p=0·0038), and those infected with the B.1.1.7 (alpha) SARS-CoV-2 variant had higher C19-RS values than those infected with the wild-type SARS-CoV-2 variant (adjusted OR 1·89 [95% CI 1·17-3·20] per SD, p=0·012). C19-RS had prognostic value for in-hospital mortality in COVID-19 in two testing cohorts (high [≥6·99] vs low [

Treatment of severe COVID-19 is currently limited by clinical heterogeneity and incomplete description of specific immune biomarkers. We present here a comprehensive multi-omic blood atlas for patients with varying COVID-19 severity in an integrated comparison with influenza and sepsis patients versus healthy volunteers. We identify immune signatures and correlates of host response. Hallmarks of disease severity involved cells, their inflammatory mediators and networks, including progenitor cells and specific myeloid and lymphocyte subsets, features of the immune repertoire, acute phase response, metabolism and coagulation. Persisting immune activation involving AP-1/p38MAPK was a specific feature of COVID-19. The plasma proteome enabled sub-phenotyping into patient clusters, predictive of severity and outcome. Systems-based integrative analyses including tensor and matrix decomposition of all modalities revealed feature groupings linked with severity and specificity compared to influenza and sepsis. Our approach and blood atlas will support future drug development, clinical trial design and personalized medicine approaches for COVID-19., Graphical Abstract, A multi-omic analysis of patient blood samples reveals both similarities and specific features of COVID-19 when compared with samples obtained from sepsis or influenza patients which could yield better targetted therapies for severe COVID-19.

Patients chronically infected with hepatitis C virus (HCV) frequently develop mixed cryoglobulinemia (MC), a monoclonal expansion of immunoglobulin M (IgM)+ autoreactive B cells, and also have an increased B-cell lymphoma risk. Whether HCV infection also impacts the B-cell compartment and the B-cell receptor repertoire in patients not affected by MC or lymphomas is poorly understood. Flow cytometric analysis of peripheral blood B cells of 30 MC-negative HCV-infected patients and 15 healthy controls revealed that frequencies of class-switched memory B cells were increased in the patients, whereas frequencies of transitional and naive B cells were decreased. For 22 HCV+ patients and 7 healthy controls, we performed high-throughput sequencing of immunoglobulin heavy chain VDJ rearrangements of naive, mature CD5+, IgM+ memory, and class-switched memory B cells. An increased usage of several IGHV genes, including IGHV1-69 and IGHV4-59, which are closely linked to MC and HCV-associated lymphomas, was specifically seen among IgM+ memory B cells of the patients. Moreover, many, and partly very large, expanded clones were seen predominantly among IgM+ memory B cells of all HCV-infected patients analyzed. Thus, chronic HCV infection massively disturbs the B-cell compartment even in patients without clinically detectable B-cell lymphoproliferation and generates many large B-cell clones, especially among non-class-switched memory B cells. Because B-cell clones in MC and lymphomas derive from this B-cell subset, this establishes IgM+ memory B cells as a general target of lymphoproliferation in HCV+ patients, affecting apparently all patients.

Mixed cryoglobulinemia (MC) is a lymphoproliferative disorder observed in ∼10 to 15% of hepatitis C virus (HCV)-infected patients. Circulating, nonenveloped HCV core protein, which has been detected in cryoprecipitable immune complexes, interacts with immunocytes through the receptor for the globular domain of C1q protein (gC1q-R). In this study, we have evaluated circulating gC1q-R levels in chronically HCV-infected patients, with and without MC. These levels were significantly higher in MC patients than in those without MC and in healthy controls and paralleled specific mRNA expression in PBL. Soluble gC1q-R circulates as a complexed form containing both C1q and HCV core proteins. Higher serum gC1q-R levels negatively correlated with circulating concentrations of the C4d fragment. The presence of sequestered C4d in the vascular bed of skin biopsies from MC patients was indicative of in situ complement activation. In vitro studies showed that release of soluble gC1q-R is regulated by HCV core-mediated inhibition of cell proliferation. Our results indicate that up-regulation of gC1q-R expression is a distinctive feature of MC, and that dysregulated shedding of C1q-R molecules contributes to vascular cryoglobulin-induced damage via the classic complement-mediated pathway.

Recognition of hepatitis C virus (HCV) as an etiological factor in mixed cryoglobulinemia (MC) has dramatically changed our point of view in its treatment. Emphasis is placed on abatement and clearance of viral load and deletion of clonal expansions of IgM molecules with rheumatoid factor activity-synthesising B cells. The purpose of this review is to discuss the underlying scientific rationale and results of clinical studies of new treatment approaches to MC, with a focus on cell-depleting therapies and chemokine blockade. Additional antiviral agents directed to several phases of HCV life cycle acting with different or alternate mechanisms are proposed with the goal to enhance response rates more broadly suitable for MC patients with vasculitis and peripheral neuropathies. The majority of the available data on these new treatment approaches stems from open-label studies, but controlled trials are under way. Therapy directed against chemokines and/or cytokines represents an interesting and promising future target.

Summary The relationship between the occurrence of cryoglobulins and hepatitis C virus (HCV) productive infection in peripheral blood and bone marrow-derived lymphocytes was explored. HCV minus strand RNA, the viral replicative intermediate, was searched for by a polyA+ tract strand-specific Tth-based reverse transcriptase–polymerase chain reaction (RT–PCR) in lymphoid cells of 46 patients with acute and chronic infection. The HCV minus strand was demonstrated in RNA extracted from six (13%) and five (11%) peripheral blood and bone marrow-derived lymphocytes, respectively. The HCV replicating form in lymphoid cells was associated strictly with mixed cryoglobulinaemia (MCG), in that it was found in six of 13 (46%) MCG patients, including two with B cell non-Hodgkin's lymphoma (NHL). No traces of HCV-negative strand RNA were found in four patients with acute hepatitis C, in 15 with chronic active hepatitis without extrahepatic disorders, in seven with monoclonal gammopathy of undetermined significance, and in seven with B-NHL without MCG. These results emphasize the direct role of the virus in the pathogenesis of MCG and support the contention that HCV is not specifically lymphotropic, its entry and replication in lymphoid cells being determined largely by selective interactions.

B cell repertoire in three biological compartments (liver, bone marrow and peripheral blood) of 30 unselected patients chronically infected with HCV has been characterized. Restriction of humoral immune response defined by enrichment of B cell clonal expansions occurred in the liver of 15 patients (50%), in the bone marrow and peripheral blood of 2 (6.7%) and 8 (26.7%) patients, respectively. An in situ hybridization technique was developed for the detection of dominant B cell clones in patients with monoclonal expansions. It was shown that morphologically distinct B cell expansion contributes to the formation of intraportal follicle-like structures. Sequence analyses of CDRH3 gene segments revealed a wide range of variations. Clones derived from the same founder were demonstrated simultaneously in the three compartments explored. The occurrence of B cell clonal expansions profoundly influenced the clinical expression of HCV infection, since it was associated with extrahepatic manifestations. In sharp contrast, no extrahepatic signs or disease occurred in patients without evidence of intrahepatic B cell clonalities. These findings emphasize the profound B cell function derangement in at least half of HCV-infected patients. Thus, the restriction of V gene usage has a direct impact on the clinical spectrum of HCV infection.

A controlled study has been carried out to assess the efficacy of rituximab, a chimeric antibody that binds to the B-cell surface antigen CD20, in 20 patients with mixed cryoglobulinemia (MC) and hepatitis C virus (HCV)–positive chronic active liver disease, resistant to interferon α (IFN-α) therapy. They received an intravenous infusion of 375 mg/m2 rituximab once a week for 4 consecutive weeks. Infusion of rituximab had a good safety profile and no severe side effects were reported. Sixteen patients (80%) showed a complete response (CR), characterized by rapid improvement of clinical signs (disappearance of purpura and weakness arthralgia and improvement of peripheral neuropathy), and decline of cryocrit. CR was associated with a significant reduction of rheumatoid factor (RF) activity and anti-HCV antibody titers. Decline of IgG anti-HCV titers in the cryoprecipitates was usually associated with a favorable response (r = 0.81; P

Cryoglobulins are cold-precipitable immunoglobulins associated with a number of infectious, autoimmune and neoplastic disorders. Their appearance along with rheumatoid factor (RF) can be considered a normal event in the clearance of immune complexes and rarely produces any symptoms. The association between hepatitis C virus (HCV) and mixed cryoglobulinemia (MC) has been rendered evident since the recognition of serological markers of HCV infection. There is thus every reason to suppose that direct or indirect involvement of B cells on the part of the HCV results in their persistent stimulation, clonal expansion and release of molecules with RF activity. The formation of RF/IgG immune complexes is the key pathogenetic mechanism. The close correlation between HCV infection and MC also throws new light on the interpretation of autoimmune phenomena in the course of viral infection and on the close link between autoimmune diseases and lymphoproliferative disorders. The higher risk of non-Hodgkin's lymphoma (NHL) displayed by HCV positive subjects, especially in the Mediterranean basin, suggests that the HCV's chronic lymphoproliferative drive may progress towards frank lymphoid neoplasia. The presence of MC does not represent an in situ or 'occult' NHL, because recent evidences indicate that none of the clones interpreted as predominant displays the molecular features of a true neoplastic process. The cryoglobulinemic syndrome is probably the consequence of pathogenic noxae that act upon the immune system of a host in which regulation of the peripheral T cell response appears to be in some way altered.

Chronic infection with hepatitis C virus (HCV) often affects the B-cell compartment, leading to the occurrence of autoimmunity and B-cell lymphoproliferation, in particular mixed cryoglobulinemia and B-cell lymphomas. HCV presumably causes these lymphoproliferations by chronic antigenic stimulation and/or direct mutagenic effects on B cells. It has been speculated that the interaction of HCV with B cells and the expansion of antigen-triggered B cells happens in germinal center-like structures in the livers of HCV carriers. We studied rearranged immunoglobulin V(H) genes from seven B-cell follicles microdissected from the livers of three unselected chronic HCV patients. The follicles consisted of polyclonal naive and memory B-cell populations with only rare indication of minor clonal expansions and no evidence for active somatic hypermutation. Frequent detection of V(H) rearrangements using the VH1-69 gene segment nevertheless indicated that at least a fraction of the B cells is HCV-specific and/or autoreactive. Thus, the typical intrahepatic B-cell follicles in chronic HCV carriers do not function as ectopic germinal centers for clonal expansion and affinity maturation of B cells. Hence, autoreactive and HCV-specific B-cell clones might either develop in secondary lymphoid organs or in intrahepatic follicles only under particular, yet undefined, circumstances.

Hepatitis C virus (HCV) is considered to have a causative role in B-cell lymphoproliferative diseases, including B-cell lymphomas, in chronic virus carriers. Previous data from in vitro HCV-infected B-cell lines and peripheral blood mononuclear cells from HCV-positive individuals suggested that HCV might have a direct mutagenic effect on B cells, inducing mutations in the tumor suppressor gene TP53 and the proto-oncogenes BCL6 and CTNNB1 (β-catenin). To clarify whether HCV indeed has a mutagenic effect on B cells in vivo , we analyzed naive and memory B cells from the peripheral blood of four chronic HCV carriers and intrahepatic B cells from the livers of two HCV-positive patients for mutations in the three reported target genes. However, no mutations were found in the TP53 and CTNNB1 genes. For BCL6, which is a physiological target of the somatic hypermutation process in germinal-center B cells, the mutation levels identified were not higher than those reported in the respective B-cell subsets in healthy individuals. Hence, we conclude that in chronic HCV carriers, the virus does not generally induce mutations in the cancer-related genes TP53, CTNNB1, and BCL6 in B cells. Based on these findings, new targets have to be investigated as potential mediators of HCV-associated B-cell lymphomagenesis.

This study illustrates the use and efficacy of a combination of pegylated interferon-α (Peg-IFN-α) and ribavirin (RBV), with or without rituximab (RTX), in hepatitis C virus (HCV)–related mixed cryoglobulinemia (MC). Twenty-two patients with HCV-related MC received Peg-IFN-α (2a: 180 μg or 2b: 1.5 μg/kg) weekly plus RBV (1000 or 1200 mg) daily for 48 weeks, and RTX (375 mg/m2) once a week for 1 month followed by two 5-monthly infusions (termed PIRR). Fifteen additional patients received Peg-IFN-α/RBV with the same modalities as the PIRR schedule. Complete response was achieved in 54.5% (12/22) and in 33.3% (5/15) of patients who received PIRR and Peg-IFN-α/RBV, respectively (P < .05). Clearance of HCV RNA and conversion of B-cell populations from oligoclonal to polyclonal in liver, bone marrow, and peripheral blood was maintained for up to 3 years in 10 of 12 (83.3%) and in 2 of 5 (40%) patients receiving PIRR and Peg-IFN-α/RBV, respectively (P < .01). Cryoproteins in 22.7% (5/22) of patients with PIRR and in 33.3% (5/15) with Peg-IFN-α/RBV persisted despite sustained HCV RNA clearance. No response occurred in remaining 5 patients of both groups. PIRR therapy is well tolerated and more effective than Peg-IFN-α/RBV combination in HCV-related MC. Its effect may last for more than 3 years.

Chemokine CXCL13, also known as BCA-1 (B cell–attracting chemokine-1) or BLC (B-lymphocyte chemoattractant), is a major regulator of B-cell trafficking. Hepatitis C virus (HCV) infection may be associated with B-cell dysfunction and lymphoproliferative disorders, including mixed cryoglobulinemia (MC). This study evaluates circulating levels of CXCL13 protein and specific mRNA expression in chronically HCV-infected patients with and without MC. Compared with healthy controls and HCV-infected patients without MC, CXCL13 serum levels were significantly higher in MC patients. The highest CXCL13 levels strongly correlated with active cutaneous vasculitis. CXCL13 gene expression in portal tracts, isolated from liver biopsy tissues with laser capture microdissection, showed enhanced levels of specific mRNA in MC patients with active cutaneous vasculitis. Specific CXCL13 gene mRNA expression was also up-regulated in skin tissue of these patients. These findings paralleled specific deposits of CXCL13 protein both in the liver and in the skin. Our results indicate that up-regulation of CXCL13 gene expression is a distinctive feature of HCV-infected patients. Higher levels of this chemokine in the liver as well as in the skin of patients with active MC vasculitis suggest a possible interrelation between these biologic compartments.

A controlled study has been carried out to assess the efficacy of rituximab (RTX), a chimeric antibody that binds to the B-cell surface antigen CD20, in twenty patients with mixed cryoglobulinemia (MC) and HCV-positive chronic active liver disease, resistant to interferon-alpha (IFN-alpha) therapy. They received an intravenous infusion of 375 mg/m(2) RTX once a week for 4 consecutive weeks. Infusion of RTX had a good safety profile, and no severe side-effects were reported. Sixteen patients (80%) had a complete response (CR), characterized by rapid improvement of clinical signs (disappearance of purpura, weakness, arthralgias and improvement of peripheral neuropathy), and decreased cryocrit. CR was associated with a significant reduction in rheumatoid factor (RF) activity and anti-HCV antibody titers. Decline of IgG anti-HCV titers in the cryoprecipitates was usually associated with a favorable response (r= 0.81; p

We demonstrate that in three cases of MC (two with immunocytoma), the IgM-RF+ component of their cryoprecipitated represents the circulating counterpart of the B-cell receptor (BCR) of the monoclonal overexpanded B-cell population. These IgMs were isolated and used to demonstrate a crossreactivity against both hepatitis C virus (HCV) NS3 antigen and the Fc portion of IgG. Epitopes were identified in a fraction of exemplary samples by using epitope excision approach (NS(31250-1334) and IgG Fc(345-355)). The same phenomenon of crossreactivity has been shown to occur in vivo after immunization of a mouse with the NS3(1251-1270) peptide. To verify if the same reaction was also present in MC samples characterized by an oligo/polyclonal B-cell proliferation, IgM crossreactivity was tested in 14 additional samples. Five out of the 14 were reactive against HCV NS3 and 11 out of 14 were reactive against IgG-Fc peptide. The data support the role of HCV NS3 antigen in a subset of patients with MC, whereas the high frequency of the IgG-Fc epitope suggests that these B cells originate from precursors strongly selected for auto-IgG specificity. We suggest that engagement of specific BCRs by NS3 (or NS3-immunocomplex) antigen could explain the prevalence of IgM cryoglobulins in these patients.

Objective. To identify and characterize rheumatoid factor (RF)-producing B-cells and cryoprecipitate immunoglobulin (Ig) M in hepatitis C virus (HCV)-positive patients. Methods. We purified and characterized, by peptide mass fingerprinting integrated with an NCBI IgBlast data bank search, the IgM component of cryoprecipitate and analysed the VDJ pattern of bone marrow B-cells by gene scan analysis of 17 HCV-positive patients with type II mixed-cryoglobulinaemia. Results. IgM purified from all of the patients presented an RF specificity. In three of these patients a high and predominant B-cell clone (¸30%) was found in the bone marrow. B-cell-receptor sequences were determined and immunophenotyping of these clones was performed. Peptide masses originating after tryptic digestion of the B-cell-receptor combinatory regions and those originating by tryptic digestion of the cryoprecipitated IgM from the same patient were comparable. In the remaining patients an oligoclonal/polyclonality was found. However, in some of these patients we were able to find peptides that matched with the B-cell-receptor sequences of overexpanded B cells, indicating that, even in the absence of a clear monoclonal expansion, a fraction of total cryoprecipated IgM may derive from overexpanded B-cell clones found in patients’ bone marrow. Conclusions. In the majority of mixed cryoglobulinaemia-HCV-positive patients, both in the serum and in B cells from the bone marrow, an oligoclonal pattern is the main molecular picture. When a monoclonal B-cell clone is found, its B-cell-receptor shows an antigen-binding fragment identical to that of cryoprecipitable RF-IgM. Phenotypically, B cells are CD20-positive but CD5-negative, suggesting that the B-1 B-cell subset is not likely to produce high-affinity IgM-RF molecules. The term cryoglobulinaemia refers to the presence in the serum of one (monoclonal cryoglobulinaemia) or more (mixed cryoglobulinaemia, MC) immunoglobulins (Ig), which precipitate at temperatures below 378C. This is an in vitro phenomenon; the real mechanism(s) of cryoprecipitation remains obscure. Cryoglobulins are classified according to Brouet’s criteria [1]. MC consists of polyclonal Ig G and either polyclonal (type III; MC-III) or monoclonal (type II; MC-II) IgM rheumatoid factors (RFs). MC-II is frequently associated with development of serious vascular, renal and neurological lesions; B-cell clonal expansions are also a frequent laboratory finding. Oligoclonal or monoclonal B-cell expansions are significant features of liver, peripheral blood and bone marrow, and are associated with clinical manifestations and laboratory data [2]. MC-II has been associated with higher risk of non-Hodgkin’s lymphoma (NHL) [3] and, although more controversial, with cirrhosis [4]. Ectopic lymphoid follicles generally express IgM and the limited number of family genes used to construct the antigen-binding fragment (Fab) suggest the possibility that chronic antigenic stimulation contributes to B-cell expansion [5]. Eighty per cent of the monoclonal IgMs found in hepatitis C virus positive patients with a type II mixed cryoglobulinaemia(HCV-MC) patients share a major complementary region named WA. This WA crossing idiotype has been long recognized to be associated with a high degree of RF activity. These antibodies almost invariably express an IgH variable heavy (VH) chain derived from the V1-69 germinal gene and an IgK variable light chain (VL) derived from the V3-20 germinal gene [6]. Approximately 25% of B-NHLs in patients with HCV type II cryoglobulinaemia appeared to arise from WA cross-reactive B cells, and about 70% of light chain of Ig are from V3-20 or V3-15 germline genes [7, 8]. Other VH/VK gene combinations frequently found in MC-associated NHLs were V3-7/V3-15 and V4-59/V3-20 [9]. All this evidence suggests that the malignant cells could derive from the RF-producing B-cells that sustain of the MC syndrome. However, a direct link between clonal B-cell proliferation and production of the IgM component of the cryoprecipitate still remains to be demonstrated. Clinical and epidemiological evidence and laboratory investigations have established the pathogenic role of HCV in MC-II. Furthermore, HCV is the most prevalent hepatotropic virus in

Infection with HCV can be associated with B-cell non-Hodgkin lymphoma. Polymerase chain reaction (PCR) amplification assays for Bcl-2/IgH rearrangement were performed on nucleic acids extracted from portal tract inflammatory infiltrates, isolated with laser capture microdissection (LCM), from liver biopsy sections of 16 hepatitis C virus (HCV)-infected patients with and without extrahepatic B cell–related disorders. Results were compared with total DNA extracted from core liver biopsy specimens and from peripheral blood mononuclear cells (PBMCs). We failed to demonstrate specific Bcl-2/IgH amplicons either in liver tissue or in PBMCs in all patients of the current series. Multiple PCR assays for variable diversity joining (VDJ) IgH gene rearrangements were also performed in the liver compartment. Selective amplification compatible with mono or oligoclonal B cell clonotypes was demonstrated in 80% (6/8) and 25% (2/8) of patients with and without clinical evidence of B-cell disorders. VH1 and VH3 were the most represented VH families. In situ expression of Bcl-2 protein was carried out by immunohistochemistry on liver biopsy sections. Bcl-2 protein was detected in 2 (12.5%) patients who did not associate extrahepatic disorders. In conclusion, current data support the concept that production of IgH gene rearrangements is not associated with Bcl-2/IgH chromosomal translocation in hepatic compartment. Liver overexpression of Bcl-2 protein may occur in at least a minor proportion of HCV-infected patients. (HEPATOLOGY 2005.)

In addition to cause acute and chronic liver disease, hepatitis C virus (HCV) infection is frequently associated to autoimmune disorders, such as mixed cryoglobulinemia, primary glomerulonephritis, monoclonal gammopathy of undetermined significance and post-transplant proliferative disorders. Progression to malignant phenotype of B cells may be the consequence of additional genetic events or abnormal conditions resulting from modification of host cell genes involved in the control of oncogenes and oncoproteins. In this review, we will address the potential immune disregulatory mechanism(s) underlying HCV persistence. In addition, HCV/B-cell interaction that might explain defects in humoral immunity in individuals who develop chronic virus carriage and lymphoproliferative disorders will be emphasized.

Conclusions: This study confirms the effectiveness and safety of Rituximab in MC and shows its safety also in patients with advanced cirrhosis. Moreover, the Rituximab-related depletion of CD20+B-cells was followed by cirrhosis improvement in spite of a moderate and inconstant increase of both viraemia and ALT values. The mechanisms involved are unknown. Interesting working hypotheses may implicate a role played by direct B-cell hepatotoxicity with the contribution of B-cell infiltrates in conditioning liver damage. The improvement of Kuppfer cell function due to the cryocrit value reduction might also play a role.

PCR DNA amplification of IgH genes was performed on liver biopsy samples of 42 unselected hepatitis C virus (HCV)-positive patients. Genotypic analysis and signal amplification by branched DNA were used to characterize and quantitate HCV RNA genomic sequences. Intraportal lymphoid follicle-like structures were isolated from surrounding hepatocytes by microdissection technique. IgH VDJ PCR products were cloned and sequenced. IgH VDJ gene rearrangements were detected in the liver of 26 (62%) patients. Unequivocal monoclonal or oligoclonal patterns of B cell expansions were found in 14 (33.3%) and 12 (28.6%) patients, respectively. Patients with intrahepatic B cell monoclonal expansions showed liver HCV RNA levels higher than those with oligoclonal or polyclonal features (1106.4 ± 593.5 vs 677.3 ± 424.3 vs 406.2 ± 354.3 pg HCV RNA/g tissue; p = 0.048 and p = 0.001, respectively). Although a single dominant band was obtained with total DNA, characterization of DNA recovered from intraportal inflammatory aggregates resulted in the detection of multiple IgH VDJ gene rearrangements, pointing to an oligoclonal pattern of lymphoproliferation. Cloning and sequence analyses showed that B cell clonalities were differently distributed in adjacent portal tracts of the same liver area. In addition, HCV RNA genomic sequences could be consistently amplified from each of the portal inflammatory aggregates examined. These data support the concept that in chronic HCV infection the intrahepatic B cell repertoire is frequently clonally restricted and that HCV may have a direct role in sustaining in situ B cell proliferation.