Persistence of hepatitis C virus in a human megakaryoblastic leukaemia cell line

Abstract

Thrombocytopenia is a frequent clinical finding in patients with hepatitis C virus (HCV) infection. Platelets from patients with HCV infection have been identified as carriers of HCV RNA in our previous studies. The present study was designed to further investigate the possibility of HCV replication in megakaryoblasts from which platelets are eventually released. A megakaryoblastic cell line (MEG-01), established from a chronic myelogenous leukaemia patient 13 years ago, was used for this study. The MEG-01 cells were inoculated with fresh serum from a patient with HCV infection and renamed MEG-01-I cells. Surprisingly, both MEG-01 and MEG-01-I were positive by HCV reverse transcription-polymerase chain reaction (RT-PCR) for the existence of HCV RNA and minus-strand HCV RNA, regardless of inoculation. This was further confirmed by in situ RT-PCR. The HCV antigens, such as core, envelope, and non-structural (NS)3 and NS4, were also present in both cell lines, as identified by Western blotting and indirect immunofluorescence staining. In addition, virus-like particles were observed by electron microscopy in the MEG-01 cell line as well as in the MEG-01-I cell line. These findings indicate that the megakaryoblasts are vulnerable to HCV infection and that replication of HCV can occur in these cells. This may help us to better understand the pathogenesis of thrombocytopenia in patients with HCV infection. The MEG-01 cell line, which may have been continuously shedding HCV for years, should be a useful model for experimental research into HCV.

Platelets and viruses: an ambivalent relationship

“…It seems that the endocytic pathway is relevant in human pathology since ultrastructural images of intact viruses were found in bone marrow MKs from HIV infected patients [7]. Viral replication in MKs has been demonstrated for several viruses like HIV-1 [33], HCV [34], and human CMV (HCMV) [29]. For example, in purified marrow MKs from HIV-seropositive patients with immune thrombocytopenic purpura, viral transcripts, and small amounts of HIV glycoproteins were detected although heterogeneity among MK was observed [35].…”

Risk of Immune Thrombocytopenic Purpura and Autoimmune Hemolytic Anemia Among 120 908 US Veterans With Hepatitis C Virus Infection

“…[36, 37] Third, there has been evidence that HCV can infect and replicate in megakaryocytes, leading to their depletion. [38, 39] The fact that AIHA and ITP are both autoimmune cytopenias, but HCV infection appears to be associated with only ITP, supports the hypothesis that beyond a mechanism of generalized autoimmunity, chronic HCV infection may also cause ITP through a platelet specific mechanism. Of note, ITP is formally defined by the presence of isolated thrombocytopenia without another identifiable etiology or associated condition.…”

HCV infective virions can be carried by human platelets

“…However, remembering that HCV possesses the ability to infect haematopoietic progenitor cells as has been demonstrated by Sansonno et al, 19 we think that the same phenomenon could also explain this type of HCV-correlated pathology. In fact Li et al 20 demonstrated that HCV can infect megakaryoblastic cells.…”