Enhanced Activation of Memory, but Not Naïve, B Cells in Chronic Hepatitis C Virus-Infected Patients with Cryoglobulinemia and Advanced Liver Fibrosis

Abstract

Mixed cryoglobulinemia is the most common extrahepatic disease manifestation of chronic hepatitis C virus (HCV) infection, where immunoglobulins precipitate at low temperatures and cause symptoms such as vasculitis, glomerulonephritis and arthralgia. HCV-associated cryoglobulinemia is also strongly linked with the development of B cell non-Hodgkin lymphoma. Abnormal B cell function in HCV infections can lead to the formation of HCV cryoglobulin complexes that usually comprise monoclonal rheumatoid factor and HCV-specific immune complexes. The aim of this study was to characterize the activation phenotype of B cells from patients with chronic HCV infection in comparison to healthy controls using flow cytometry. In addition, we determined how the activation status varies depending on the presence of cryoglobulinemia and advanced liver fibrosis. We found that only memory B cells, not naïve cells, were significantly activated in chronic HCV infection when compared with healthy controls. We also identified markers of memory B cell activation that were specific for HCV patients with cryoglobulinemia (CD86, CD71, HLA-DR) and advanced liver disease (CD86). Our results demonstrate that HCV infection has differential effects on B cells depending on the severity of hepatic and extrahepatic disease.

A Small Molecule Inhibits Virion Attachment to Heparan Sulfate- or Sialic Acid-Containing Glycans

“…Viral RNA from each fraction was eluted using the Roche High Pure viral nucleic acid kit (Roche, Laval, QC, Canada), according to the manufacturer's instructions. The RNA was transcribed to cDNA using Superscript III reverse transcriptase (Invitrogen, Burlington, ON, Canada) and an HCV-specific primer (5=-GTG TTT CTT TTG GTT TTT CTT TGA GGT TTA GG-3=) (43). Quantitative real-time PCR was performed using the 7900HT Fast real-time PCR system (Applied Biosystems) and TaqMan universal PCR master mix (Applied Biosystems).…”

“…Quantitative real-time PCR was performed using the 7900HT Fast real-time PCR system (Applied Biosystems) and TaqMan universal PCR master mix (Applied Biosystems). We used primers amplifying the conserved 5=-untranslated region of the HCV genome (5=-TCT GCG GAA CCG GTG AGT A-3= and 5=-GTG TTT CTT TTG GTT TTT CTT TGA GGT TTA GG-3=) and 5=-6-carboxyfluorescein (6-FAM)-CAC GGT CTA CGA GAC CTC CCG GGG CAC-6-carboxytetramethylrhodamine (TAMRA)-3= as the HCV-specific detection probe (43,44). Ten-fold dilutions from 10 1 to 10 6 copies of a linearized plasmid containing the sequence of HCV JFH-1 were used to generate a standard curve for quantitation.…”

Chronic hepatitis C virus infection and lymphoproliferative disorders: Mixed cryoglobulinemia syndrome, monoclonal gammopathy of undetermined significance, and B‐cell non‐Hodgkin lymphoma

“…The supernatant was incubated at 4°C for 7 days and examined for cryoprecipitate. MCS was diagnosed on the basis of serological findings (mixed cryoglobulins with rheumatoid factor activity) and clinical features such as purpura, arthralgia, fatigue, and vasculitis …”

Skewed B cells in chronic hepatitis C virus infection maintain their ability to respond to virus‐induced activation

“…In line with this, chronic hepatitis C virus (HCV) infection may be associated with extrahepatic manifestations caused by continuous antigenic stimulation, including lymphoproliferative disorders, such as mixed cryoglobulinemia and low‐grade non‐Hodgkin B‐cell lymphomas (NHL), as well as autoimmunity . Several lines of evidence indicate that both naïve and memory B cells are activated during HCV infection with or without concomitant pathological lymphoproliferation and that considerable B‐cell subset skewing is present, with immature transitional and activated memory B cell subset frequencies being increased in HCV‐infected subjects . Abnormalities of B‐cell phenotype were associated with altered cell cycling (immature transitional B cells) and an intrinsic resistance to apoptosis (activated memory B cells), suggesting that altered B‐cell function was restricted to selected B‐cell subsets in chronic hepatitis C .…”