B-cell activating factor (BAFF), BAFF promoter and BAFF receptor allelic variants in hepatitis C virus related Cryoglobulinemic Vasculitis and Non-Hodgkin's Lymphoma.

Cryoglobulinemic Vasculitis (CV) is an autoimmune/lymphoproliferative disorder associated with HCV infection that in 5%-10% of cases evolves into a B cell Non-Hodgkin's Lymphoma (NHL). B-cell activating factor (BAFF) is a key regulator in B-cell development and survival. Particular genetic variants are responsible for BAFF signaling impairment in autoimmune and neoplastic diseases. We evaluated BAFF and BAFF-receptor (BAFF-R) polymorphisms in order to determine if they predispose to HCV-related CV and NHL. The analysis was performed on 416 HCV-chronically infected patients: 136 HCV without signs/symptoms of lymphoproliferations/autoimmunity (HCV), 166 HCV with CV (HCV-CV) and 114 HCV with NHL (HCV-NHL). Rs9514828 SNP on BAFF promoter, rs61756766 on BAFF-R and rs12428930 on the BAFF gene were evaluated by Real-Time PCR. Concerning rs9514828, the frequency of C/T genotype was significantly higher in HCV-CV than in HCV. The difference in the distribution of the T/T mutant genotype in HCV-CV compared to HCV was significant as well as the distribution of C/T and T/T genotype in HCV-NHL versus HCV. T minor allele was more frequent in HCV-NHL and HCV-CV than in HCV. The distribution of C/T + T/T (for the dominant model of penetrance C/T + T/T vs. C/C) was significantly higher in HCV-CV and HCV-NHL than in HCV. Genotyping of rs61756766 on BAFF-R coding gene, revealed C/T heterozygosis at a frequency of 11% in HCV-NHL versus 3% in HCV. The T minor allele frequency was higher in HCV-NHL than in HCV. No differences emerged by genotyping rs12428930 SNP on BAFF coding gene. Our results reinforce the hypothesis that BAFF/BAFF-R genetic pattern has a role in the pathogenesis of HCV-related lymphoproliferations. BAFF/BAFF-R variants could identify a risk haplotype for HCV related CV and NHL and a BAFF/BAFF-R genetic profile assessment could potentially contribute to tailoring anti-BAFF therapy by identifying patients with BAFF alterations in which the treatment could be more beneficial.

Genetic Association of Hepatitis C-Related Mixed Cryoglobulinemia: A 10-Year Prospective Study of Asians Treated with Antivirals.

Genetic profiles of hepatitis C virus (HCV)-associated mixed cryoglobulinemia (MC) in Asians remain elusive. A 10-year prospective cohort study was conducted with 1043 consecutive HCV Ab-positive Taiwanese surveyed with 13 single nucleotide polymorphisms (SNPs). Of 1043, 589 (56.5%) had baseline MC, 934 (89.5%) had positive HCV RNA, 796 completed anti-HCV therapy, and 715 had sustained virological responses (SVRs). SNP associations were surveyed withgenotypic, allelic, trend, permutation and multivariate analyses. At baseline, higher male sex and MC rates were noted in HCV RNA-positive than RNA-negative patients; higher female sex and positive HCV RNA rates but lower HCV RNA levels were noted in patients with than those without MC. Baseline associations were: HLA II-rs9461776 A allele, IFNL3-rs12979860 T allele, SERPINE1-rs6976053 C allele and MC with HCV RNA positivity; IFNL3-rs12979860 C allele, ARNTL-rs6486122 T allele and HCV RNA positivity with baseline MC. In SVR patients, RETN-rs1423096 C allele and SERPINE1-rs6976053 T allele were associated with 24-week and 10-year post-therapy MC, respectively. Conclusions: HCV RNA, IFNL3-rs12979860 and ARNTL-rs6486122 were associated with baseline MC; RETN-rs1423096 and SERPINE1-rs6976053 were associated with short- and long-term post-therapy MC in SVR patients, respectively. Links with HCV RNA and immune-associated SNPs suggest MC an immune reaction to expel HCV.

Hematological and Genetic Markers in the Rational Approach to Patients With HCV Sustained Virological Response With or Without Persisting Cryoglobulinemic Vasculitis.

BACKGROUND AND AIMS: Direct-acting antivirals (DAAs) usually lead to improvement/remission of cryoglobulinemic vasculitis (CV), although symptoms may persist/recur after a sustained virological response (SVR). We evaluated hematological and genetic markers in patients with HCV-SVR vasculitis with and without persisting/recurring symptoms to early predict the CV outcome. APPROACH AND RESULTS: Ninety-eight patients with HCV-CV were prospectively enrolled after a DAA-induced SVR: Group A: 52 with complete clinical response; Group B: 46 with symptom maintenance/recurrence. Monoclonal B-cell lymphocytosis, t(14;18) translocation, and abnormal free light chains κ/λ ratios were detected by flow cytometry or nested-PCR or nephelometry in 4% Group A versus 17% Group B (P = 0.04) patients, 17% Group A versus 40% Group B patients (P = 0.02), and 17% Group A versus 47% Group B (P = 0.003) patients, respectively. At least 1 out of 3 clonality markers was altered/positive in 29% of Group A versus 70% of Group B patients (P < 0.0001). When available, pretherapy samples were also tested for t(14;18) translocation (detected in 12/37 [32%] Group A and 21/38 [55%] Group B) and κ/λ ratios (abnormal in 5/35 [14%] Group A and 20/38 [53%] Group B) (P = 0.0006), whereas at least one clonality marker was detected/altered in 16/37 (43%) Group A and 30/38 (79%) Group B (P = 0.002). CV-associated single-nucleotide polymorphisms were tested by real-time PCR. Among them, notch4 rs2071286 T minor allele and TT genotype showed a higher frequency in Group B versus Group A (46% vs. 29%, P = 0.01, and 17% vs. 2%, P = 0.006, respectively). CONCLUSIONS: Hematological or genetic analyses could be used to foresee the CV clinical response after DAA therapy and could be valuable to assess a rational flowchart to manage CV during follow-up.

Direct-acting antiviral agents for hepatitis C virus-mixed cryoglobulinaemia: dissociated virological and haematological responses.

The hepatitis C virus-positive (HCV+) mixed cryoglobulinaemia (MC) is associated with haematological alterations such as monoclonal B-cell lymphocytosis or non-Hodgkin lymphomas (NHLs). Antiviral therapy for MC, based on interferon and ribavirin, has been shown to be able to eliminate the viral replication as well as the B-cell monoclonal alterations. Many studies have reported the efficacy of direct-acting antivirals (DAAs) in the treatment of HCV+ MC. However, some authors noticed the persistence of haematological diseases despite HCV eradication. To verify the effects of DAAs on B-cell proliferation, we evaluated 67 patients with HCV+ MC. Six patients had an overt NHL and 30% had monoclonal B-lymphocytosis. In 20% of the patients, the mutation L265P of the myeloid differentiation factor 88 (MYD88) gene was detected in peripheral blood. All patients had negative HCV viraemia at week 12; one had a breakthrough, while two cases relapsed. A complete clinical response of vasculitis was seen in 60% of the patients. Among the six patients with NHL, one showed a complete response, whereas in the others there were no changes in the number and size of the nodes. Among the patients carrying a clonal population in peripheral blood, only 22% became negative. These data indicate that DAAs are not able to eliminate the clonal alterations induced by HCV in a large proportion of cases.

TREX-1-Related Disease Associated with the Presence of Cryofibrinogenemia.

PURPOSE: Cryofibrinogenemia is a rare cryopathy presenting as acrocyanosis following exposure to cold. Familial presentation has been described but the underlying molecular cause remained undetermined. METHODS: Forty (40) members from a large family with an initial diagnosis of familial cryofibrinogenemia were interviewed and examined to determine affected status and collect DNA. Exome sequencing was performed on three affected individuals from distinct branches of the pedigree. RESULTS: Seventeen (17) family members reported a history of acrocyanosis with cold exposure. None reported symptoms were suggestive of lupus. Exome sequencing of three subjects identified the heterozygous mutation D18N in the TREX1 gene which was then confirmed by Sanger sequencing in all affected as well as 2 unaffected family members. The mutation is already being associated with familial chilblain lupus erythematosus (CHLE), and a systematic review of literature was undertaken to compare reports of familial CHLE and cryofibrinogenemia. Both entities were found to share highly similar clinical presentations suggesting they are part of a same syndrome in which cryofibrinogenemia and lupus manifestations have variable penetrance. CONCLUSIONS: Familial cryofibrinogenemia without lupus should be added to the spectrum of TREX1-related disease.

DEC1/STRA13 is a key negative regulator of activation-induced proliferation of human B cells highly expressed in anergic cells.

The transcription factor DEC1/STRA13 (also known as BHLHE40 and SHARP2) is involved in a number of processes including inhibition of cell proliferation and delay of cell cycle, and is a negative regulator of B cell activation and development in mice. We show here that, unlike in mice, DEC1/STRA13 expression is induced in human naïve and memory resting B cells by activation through the B-cell receptor (BCR) or Toll-like receptor 9 (TLR9). siRNA silencing of DEC1/STRA13 increases the capacity of activated B cells to perform a high number of divisions after TLR9 ligation. This identifies DEC1/STRA13 as a critical negative regulator of clonal expansion of activated human B cells. We also show that DEC1/STRA13 is upregulated in human anergic CD21low B cells clonally expanded in patients with HCV-associated mixed cryoglobulinemia, which fail to proliferate in response to BCR or TLR9 ligation. siRNA knockdown of DEC1/STRA13, however, fails to restore responsiveness to stimuli in these cells, although it might improve the proliferative capacity in a subset of anergic cells with less pronounced proliferative defect.

[Cryoglobulinemic vasculitis in chronic hepatitis C: Genetic aspects]. / Geneticheskie aspekty krioglobulinemicheskogo vaskulita pri khronicheskom gepatite S.

Cryoglobulinemia (CG) is detected in more than 50% of patients with chronic hepatitis C (CHC); however, only 15-25% of them develop cryoglobulinemic vasculitis (CV) that is a systemic vasculitis due to the formation of immune deposits, which affects small (less than medium-sized) vessels and which is frequently fatal for the patient. The causes of CG only in some patients with CHC and the pathogenesis of CV remain unstudied; however, the accumulated data allow one to identify the special contribution of the patient's genetic factors to the development of the disease. The paper considers the genetic aspects of the development of CG and CV in CHC.

Pharmacogenetic analysis of hepatitis C virus related mixed cryoglobulinemia.

AIM: Mixed cryoglobulinemia (MC) is an extra hepatic hepatitis C virus related problem and different studies suggested genetics' role in predicting this complication. We evaluated the influence of SNPs in IL-28B, SLC29A1, SLC28A2, NT5C2, HNF4 and ABCB1 genes in MC prediction. PATIENTS & METHODS: SNPs were evaluated through real-time PCR. RESULTS:  ABCB1 (gene encoding P-glycoprotein) 3435C>T SNP was associated with MC presence (p = 0.034): related to T allele carriers (CC vs CT/TT), we reached a p-value of 0.013. In the logistic regression analysis baseline viral load >600.000 IU/ml (p < 001), IL28B rs8099917/rs12979860 TT/CC (p < 0.001), NT5 (gene encoding for 5' nucleotidase) 153 TC (p = 0.012) and ABCB1 3435 CT/TT (p = 0.034) genotypes predicted MC presence. CONCLUSION: These data could help clinicians to identify patients with higher probability to show MC extra hepatic complication.

Immunogenetics of complement in mixed cryoglobulinaemia.

OBJECTIVES: A low C4 level is one of the hallmarks of mixed cryoglobulinaemia (MC). However, several reports suggest that other factors may be involved in C4 depletion. The C4 gene is located in a multiallelic CNV locus in the human MHC region. We studied the C4 gene copy number (GCN) and both C4A and C4B isotypes, as well as the presence of the hypofunctional C4A6 allotype (rs41315824) and C4A0 allotype (rs367709216) in 41 MC patients, 16 SLE patients and 78 healthy controls. METHODS: GCN of the C4 gene were evaluated by real time PCR. C4A6 allotype (p.Arg458Trp) and ins 2-bp mutation in exon 29 were screened by primer extension. Correlation with clinical signs of the disease (cutaneous ulcers, peripheral neuropathy, GN, purpura, hepatitis) have been performed by cluster analysis, (K-means algorithm). RESULTS: C4 GCN analysis showed that fewer MC patients had more than 2 copies of the C4A gene as well as a lower C4A gene-copy index (1.90 ± 0.54 vs. 2.21 ± 0.78) as compared to healthy controls. SNP rs41315824 analysis showed a significant increase in the frequency of the p.Arg458Trp (C4A6) variant in cryoglobulinaemic patients. Lastly, cluster analysis allowed us to identify two separate clusters of patients. The cluster that included patients with three or less C4 gene copies was found to have a greater prevalence of the most severe complications such as glomerulonephritis, neuropathy and severe cutaneous ulcers. CONCLUSIONS: These data suggest there may be a relationship between polymorphisms of the C4 gene and clinical presentation.

The role of molecular mimicry and other factors in the association of Human Endogenous Retroviruses and autoimmunity.

Human Endogenous Retroviruses (HERVs) have been implicated in autoimmune and other diseases. Molecular mimicry has been postulated as a potential mechanism of autoimmunity. Exogenous viruses have also been reported to be associated with the same diseases, as have genetic and environmental factors. If molecular mimicry were to be shown to be an initiating mechanism of some autoimmune diseases, then therapeutic options of blocking antibodies and peptides might be of benefit in halting diseases at the outset. Bioinformatic and molecular modelling techniques have been employed to investigate molecular mimicry and the evidence for the association of HERVs and autoimmunity is reviewed. The most convincing evidence for molecular mimicry is in rheumatoid arthritis, where HERV K-10 shares amino acid sequences with IgG1Fc, a target for rheumatoid factor. Systemic lupus erythematosus is an example of a condition associated with several autoantibodies, and several endogenous and exogenous viruses have been reported to be associated with the disease. The lack of a clear link between one virus and this condition, and the spectrum of clinical manifestations, suggests that genetic, environmental and the inflammatory response to a virus or viruses might also be major factors in the pathogenesis of lupus and other autoimmune conditions. Where there are strong associations between a virus and an autoimmune condition, such as in hepatitis C and cryoglobulinaemia, the use of bioinformatics and molecular modelling can also be utilized to help to understand the role of molecular mimicry in how HERVs might trigger disease.

Genome-Wide Association Studies and Hepatitis C: Harvesting the Benefits of the Genomic Revolution.

Utilizing genome-wide association studies (GWASs) to examine the variation in hepatitis C virus (HCV) phenotypes has led to quantum improvements in our understanding of both the genetic basis and the underlying pathogenesis of HCV infection. In this context, the discovery of interferon lambda polymorphisms is unique with far reaching implications that extend well beyond HCV to various other liver and extrahepatic diseases. In this review, we summarize the data on the impact of GWASs on our understanding of HCV disease.

Role of IL28B genotyping in patients with hepatitis C virus-associated mixed cryoglobulinemia and response to PEG-IFN and ribavirin treatment.

The role of interleukin (IL) 28B in the treatment of chronic hepatitis C (CHC) has recently been examined in many studies, while a possible relationship between IL28B and the presence of mixed cryoglobulinemia (MC) remains to be clarified. In this study, we analyzed the influence of IL28B rs8099917/rs12979860 on the presence of MC and the role in treatment with PEG-IFN. We retrospectively examined 541 patients affected by CHC who were treated with pegylated interferon (PEG-IFN) and ribavirin from 2003 to 2012. We included all treatment-naïve patients without other viral co-infections or major contraindications to the PEG-IFN and ribavirin standard of care. One hundred seventy-five patients (32.3 %) had MC; 49 of these (33.3 %) had symptomatic MC. The IL28B rs8099917/rs12979860 TT/CC genotype was the most frequent in MC-positive patients with sustained virological response (SVR) (p < 0.001), while the TG/TC genotype was most frequent in non-SVR (p < 0.001). The TT/CC genotype was found to be the main positive predictive factor of MC in HCV patients (OR = 11.914; IQR = 7.092-18.776; p < 0.001); HCV genotype 2/3 was the strongest positive predictive factor of SVR (OR = 10.448; IQR = 8.352-21.561; p < 0.001); IL28B rs8099917/rs12979860 TT/CC was a better predictive factor than rs12979860 CC alone (OR = 9.829 vs. 2.663). Negative predictive factors were Metavir score F3-F4 (OR = 0.625; IQR = 0.416-0.779; p = 0.008), insulin-resistance (OR = 0.315; IQR = 0.224-0.585; p < 0.001) and presence of symptoms (OR = 0.716; IQR = 0.492-0.855; p < 0.001). IL28B rs8099917/rs12979860 is useful in the treatment of MC-positive HCV patients with PEG-IFN and ribavirin; the TT/CC genotype is associated with SVR, the TG/TC with non-SVR; TT/CC is also predictive of MC in HCV patients.

Thymic stromal lymphopoietin in hepatitis C virus-related cryoglobulinemic vasculitis: gene expression level and protein distribution.

INTRODUCTION: Hepatitis C virus (HCV) infection can be detected in virtually all patients with cryoglobulinemic vasculitis (CV). Among its many effects, the virus is able to stimulate the production of thymic stromal lymphopoietin (TSLP) by infected hepatocytes. In this study, we assessed the systemic levels and tissue distribution of TSLP in 60 chronically HCV-infected patients, 36 with and 24 without CV. METHODS: Serum TSLP levels were measured by an enzyme-linked immunosorbent assay (ELISA) method. TSLP mRNA was assessed in patient samples by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). TSLP protein in liver and skin biopsy samples was revealed by indirect immunofluorescence. All other methods were carried out according to standardized procedures. RESULTS: Serum TSLP levels were significantly higher in patients with than in those without CV and in healthy individuals. Higher TSLP levels paralleled specific mRNA expression and the up-regulation of TSLP protein in liver tissue. Compared with non-CV patients, higher TSLP levels in CV were accompanied by a higher frequency of circulating mono/oligoclonal B-cell expansions (8% vs. 92%, p<0.0001) and a higher number of peripheral CD20+ B-cells (10.3% vs. 15.5% p=0.04). In addition, TSLP mRNA expression in the liver of CV patients was lower than in their correspondent skin tissue and paralleled specific immune deposits of TSLP protein in keratinocytes. CONCLUSION: Overall, this study shows that TSLP secreted by hepatocytes and keratinocytes of HCV-infected patients with CV is involved in the pathogenesis of vasculitis and may possibly support the therapeutic use of TSLP-targeted monoclonal antibodies.

Genome-wide association study of hepatitis C virus- and cryoglobulin-related vasculitis.

The host genetic basis of mixed cryoglobulin vasculitis is not well understood and has not been studied in large cohorts. A genome-wide association study was conducted among 356 hepatitis C virus (HCV) RNA-positive individuals with cryoglobulin-related vasculitis and 447 ethnically matched, HCV RNA-positive controls. All cases had both serum cryoglobulins and a vasculitis syndrome. A total of 899 641 markers from the Illumina HumanOmni1-Quad chip were analyzed using logistic regression adjusted for sex, as well as genetically determined ancestry. Replication of select single-nucleotide polymorphisms (SNPs) was conducted using 91 cases and 180 controls, adjusting for sex and country of origin. The most significant associations were identified on chromosome 6 near the NOTCH4 and MHC class II genes. A genome-wide significant association was detected on chromosome 6 at SNP rs9461776 (odds ratio=2.16, P=1.16E-07) between HLA-DRB1 and DQA1: this association was further replicated in additional independent samples (meta-analysis P=7.1 × 10(-9)). A genome-wide significant association with cryoglobulin-related vasculitis was identified with SNPs near NOTCH4 and MHC Class II genes. The two regions are correlated and it is difficult to disentangle which gene is responsible for the association with mixed cryoglobulinemia vasculitis in this extended major histocompatibility complex region.

Interleukin 28B gene polymorphisms in hepatitis C virus-related cryoglobulinemic vasculitis.

OBJECTIVE: Single-nucleotide polymorphisms (SNP) in the interleukin 28B (IL-28B) gene region are strongly predictive of the response of infected patients to antiviral therapy for hepatitis C virus (HCV). We sought to determine the prevalence of SNP IL-28B rs12979860 C/C and non-C/C (C/T plus T/T) genotypes in HCV-related cryoglobulinemic vasculitis (CV), as compared with HCV-positive patients without CV. We also searched for their association with peculiar clinical manifestations of CV and potential influence on the complete response (virological, molecular, and immunological) to the therapy. METHODS: The study cohort comprised 159 and 172 HCV-infected patients with and without CV, respectively, prospectively followed starting from 1990. SNP rs12979860 genotyping was performed by Taq-Man allelic discrimination. In 106 patients (66.6%) with CV, the profile of circulating B cell clonalities was determined as well. All patients with CV were treated with pegylated interferon-α/ribavirin-based antiviral therapy. RESULTS: The T/T IL-28B genotype was more common in patients with CV than in those without (17% vs 8.1%, p = 0.02). In patients with CV, compared with non-C/C variants, the IL-28B C/C genotype was associated with a higher rate of complete response (52.6% vs 39.2%, p = 0.13), whereas a treatment response of 61.4% was demonstrated when solely virological response was considered (p = 0.008). A higher frequency of expanded B cell clonalities in the circulation (84.2% vs 55.9%; p = 0.005), kidney involvement (21% vs 2.9%; p = 0.003), and B cell non-Hodgkin lymphoma (17.5% vs 6.8%; p = 0.048), were also observed. CONCLUSION: In HCV-positive patients with CV, the IL-28B C/C genotype is distinguished biologically by a higher frequency of restriction of B cell response and clinically by a higher risk of cryoglobulinemic nephropathy and B cell malignancies, while acting as an independent predictor of a sustained virological response to antiviral therapy. In addition, we found that IL-28B T/T variant was more prevalent in patients with CV than in those without.

Somatic hypermutations confer rheumatoid factor activity in hepatitis C virus-associated mixed cryoglobulinemia.

OBJECTIVE: Hepatitis C virus (HCV) is the most frequent cause of mixed cryoglobulinemia (MC), which is characterized by endothelial deposition of rheumatoid factor (RF)-containing immune complexes and end-organ vasculitis. MC is a lymphoproliferative disorder in which B cells express RF-like Ig, yet its precise antigenic stimulus is unknown. We have proposed that IgG-HCV immune complexes stimulate B cell expansion and somatic hypermutation (SHM)-induced affinity maturation in part via engagement of an RF-like B cell receptor. This study was undertaken to test the hypothesis that SHM augments RF activity. METHODS: RFs cloned from single B cells from 4 patients with HCV-associated MC (HCV-MC) were expressed as IgM, IgG, or IgG Fab. Selected Ig were reverted to germline. RF activity of somatically mutated Ig and germline-reverted Ig was determined by enzyme-linked immunosorbent assay. RESULTS: Ig with SHM had RF activity, with the preference for binding being highest for IgG1, followed by IgG2 and IgG4, and lowest for IgG3, where there was no detectable binding. In contrast, reverted germline IgG exhibited markedly diminished RF activity. Competition with 1 µg/ml of protein A abrogated RF activity, suggesting specificity for IgG Fc. Swapping of mutated heavy-chain pairs and light-chain pairs also abrogated RF activity, suggesting that context-specific pairing of appropriate IgH and Igκ, in addition to SHM, is necessary for RF activity. CONCLUSION: SHM significantly contributes to RF activity in HCV-MC patients, suggesting that autoreactivity in these patients arises through antigen-dependent SHM, as opposed to nondeletion of autoreactive germline Ig.

Role of microRNA profile modifications in hepatitis C virus-related mixed cryoglobulinemia.

Hepatitis C virus infection is closely related to lymphoproliferative disorders (LPDs), including mixed cryoglobulinemia (MC) and some lymphomas. Modification of the expression of specific microRNAs (miRNAs) has been associated with different autoimmune diseases and/or LPDs. No data exist about the modifications in miRNA expression in HCV-associated LPDs. The aim of this study was to analyze the expression levels of a panel of miRNAs previously associated with autoimmune/LPDs in a large population of HCV patients with and without MC or non-Hodgkin's lymphoma (NHL), to identify potential markers of evolution of HCV infection. PBMC expression of miR-Let-7d, miR-16, miR-21, miR-26b, miR-146a and miR-155 was evaluated by real-time PCR in 167 HCV patients (75 with MC [MC-HCV], 11 with HCV-associated NHL [NHL-HCV], 81 without LPD [HCV]) and in 35 healthy subjects (HS). A significant increase in miR-21 (p<0.001), miR-16 (p<0.01) and miR-155 (p<0.01) expression was detected in PBMCs from only NHL patients whereas a significant decrease in miR-26b was detected in both MC and NHL subjects (p<0.01) when compared to HS and HCV groups. A restoration of miR-26b levels was observed in the post-treatment PBMCs of 35 HCV-MC patients experiencing complete virological and clinical response following antiviral therapy. This study, for the first time, shows that specific microRNAs in PBMC from HCV patients who developed MC and/or NHL are modulated differently. The specific, reversible downregulation of miR-26b strongly suggests the key role it plays in the pathogenesis of HCV-related LPDs and its usefulness as a biomarker of the evolution of HCV infection to these disorders.