Hepatitis B virus differentially suppresses myelopoiesis and displays tropism for immature hematopoietic cells

Assessment of the performance of haematological and non-invasive fibrotic indices for the monitoring of chronic HBV infection: a pilot study in a Ghanaian population

OBJECTIVE

Haematological and liver fibrotic markers could be appreciably utilized for effective monitoring of Chronic Hepatitis B viral (HBV) infection, thereby increasing patient's treatment outcome. The objective of this study was to assess the applicability of complete blood count (CBC) and non-invasive liver-fibrotic indices as markers of prognostic outcome and monitoring in HBV infections.

RESULTS

Significant differences in levels of white cell and differentials counts, red blood cell count, hemoglobin indices, and platelet indices were observed between HBV-infected patients (cases) and uninfected persons (controls). Levels of haemoglobin (Hb), total white blood cells (tWBC), neutrophils, monocytes, platelets, and Platelet Distribution width (PDW) were significantly lower (p < 0.05) in the cases compared to the controls. Total and indirect bilirubin; De-Ritis ratio, Aspartate transaminase to platelet ratio index (APRI) and RDW-to-platelet ratio (RPR) were elevated in cases compared with controls (p-value < 0.05). In a multivariate adjusted model to test the significance of markers, Hemoglobin Index (beta coefficient = - 0.876, p-value < 0.001), NLR (beta coefficient = - 0.839, p-value < 0.001), MPV_10000 (beta coefficient = - 0.333, p-value < 0.001) and Albumin (beta coefficient = - 0.059, p-value = 0.014), were associated with HBV infection status. Receiver operative characteristics curve analysis showed Hemoglobin Index (AUC = 0.744) and MPV_10000 (AUC = 0.730) as better prognostic markers for HBV-infection.

Hemolytic Anemia after Acute Hepatitis B Virus Infection: A Case Report and Systematic Review

Hemolytic anemia and pure red cell aplasia are rare hematological complications of hepatitis B virus infection. We herein report a 24-year-old man who was diagnosed with hemolytic anemia and possible transient pure red cell anemia eight weeks after a severe episode of acute hepatitis B virus infection. Rapid recovery was observed with conservative management. Hemoglobin returned to baseline within three months. As the clinical features of hemolytic anemia associated with hepatitis B virus have not yet been elucidated, we conducted a systematic review and present an analysis of the 20 reported cases, including our present case.

Relationship between Hepatitis B virus infection and platelet production and dysfunction

Hepatitis B virus (HBV) is a kind of hepatotropic DNA virus. The main target organ is liver, except for liver, HBV has been found in a variety of extrahepatic tissues, such as kidney, thyroid, pancreas, bone marrow, etc. HBV can cause severe complications by invading these tissues. Among them, pancytopenia is one of the common complications, especially thrombocytopenia that causes life-threatening bleeding. However, the mechanism of thrombocytopenia is unclear and the treatment is extremely difficult. It has been confirmed that HBV has a close relationship with platelets. HBV can directly infect bone marrow, inhibit platelet production, and accelerate platelet destruction by activating monocyte-macrophage system and immune system. While platelets act as a double-edged sword to HBV. On one hand, the activated platelets can degranulate and release inflammatory mediators to help clear the viruses. Furthermore, platelets can provide anti-fibrotic molecules to improve liver functions and reduce hepatic fibrosis. On the other hand, platelets can also cause negative effects. The infected platelets collect HBV-specific CD8⁺ T cells and nonspecific inflammatory cells into liver parenchyma, inducing chronic inflammation, liver fibrosis and hepatic carcinoma. This article explores the interaction between HBV infection and platelets, providing a theoretical basis for clinical treatment of thrombocytopenia and severe hemorrhage caused by HBV infection.

Hepatitis B Virus Replication in CD34+ Hematopoietic Stem Cells From Umbilical Cord Blood

BACKGROUND Hepatitis B virus (HBV) is a hepatotropic virus that can infect extrahepatic tissue. Whether hematopoietic stem cells (HSCs) can be infected by HBV and serve as a potential virus reservoir is still unknown. In this study, the susceptibility of CD34+ HSCs to HBV was investigated. MATERIAL AND METHODS Cord blood-derived CD34+ HSCs were exposed to HBV in vitro, and immunocytochemistry, transmission electron microscopy, and RT-PCR were used to identify viral-related proteins and specific viral genomic sequences. Then, CD34+ HSCs were challenged by different titers of HBV, and intracellular and supernatant HBV DNA, and hepatitis B surface antigen (HBsAg) levels, were examined. In addition, CD34+ peripheral blood stem cells (PBSCs) from chronic HBV carriers were isolated and cultured, and HBV DNA levels were measured. RESULTS HBV-infected CD34+ cells showed positive signals for HBsAg by DAB staining and TRITC staining, and HBV particles were identified. RT-PCR results showed that the 403 bp PCR products corresponding to the amplified hepatitis B S gene fragment were observed in CD34+ HSCs infected by HBV. In addition, supernatant and intracellular HBV DNA increased with the proliferation of CD34+ HSCs. Similar results were obtained from intracellular HBsAg quantification tests. In addition, HBV DNA levels both in cells and in supernatants of CD34+ PBSCs increased proportionally, and the increments of HBV DNA in the supernatants paralleled those found in cells. CONCLUSIONS HBV can replicate in CD34+ HSCs in cord blood or peripheral blood of chronic HBV carriers.

Possible Involvement of Hepatitis B Virus Infection of Hepatocytes in the Attenuation of Apoptosis in Hepatic Stellate Cells

Background

The induction of apoptosis in hepatic stellate cells (HSCs) is a promising therapeutic strategy against hepatitis B virus (HBV)-related hepatic fibrosis. The underlying mechanisms of apoptosis in HSCs, however, are unknown under consideration of HBV infection. In this study, the effects of HBV on apoptosis and endoplasmic reticulum (ER) stress signaling in HSCs were examined.

Methods

The effects of conditioned media (CM) from HepG2.2.15 on apoptosis induced by the proteasome inhibitor MG132 in LX-2 and HHSteC were studied in regard to c-Jun. In combination with c-Fos, c-Jun forms the AP-1 early response transcription factor, leading to AP-1 activation, signal transduction, endoplasmic reticulum (ER) stress and apoptosis.

Results

In LX-2 cells, MG132 treatment was associated with the phosphorylation of c-Jun, activation of AP-1 and apoptosis. However, in the presence of CM from HepG2.2.15, these phenomena were attenuated. In HHSteC cells, similar results were observed. HBV genomic DNA is not involved in the process of HSC apoptosis. It is possible that HBeAg has an inhibitory effect on MG132-induced apoptosis in LX-2. We also observed the upregulation of several ER stress-associated genes, such as cAMP responsive element binding protein 3-like 3, inhibin-beta A and solute carrier family 17-member 2, in the presence of CM from HepG2.2.15, or CM from PXB cells infected with HBV.

Conclusions

HBV inhibits the activation of c-Jun/AP-1 in HSCs, contributing to the attenuation of apoptosis and resulting in hepatic fibrosis. HBV also up-regulated several ER stress genes associated with cell growth and fibrosis. These mechanistic insights might shed new light on a treatment strategy for HBV-associated hepatic fibrosis.

Erythrocytosis after liver transplantation: the experience of a university hospital

The prevalence and causes of erythrocytosis after liver transplantation have never been studied, even though this condition is known to predispose patients to thrombosis leading to graft failure or death. Erythrocytosis after orthotopic liver transplantation (OLT) can be defined as an increase in the red cell mass >125% in patients without a pre-OLT history of this condition. The study population was composed of 96 patients: 33 had undergone transplantation for a hepatitis B virus (HBV) infection (18 had a hepatitis D virus coinfection), 43 had undergone transplantation for a hepatitis C virus infection, 9 had undergone transplantation for alcohol abuse, and 11 had undergone transplantation for other causes [autoimmune liver disease (6), Wilson's syndrome (1), or cryptogenetic liver cirrhosis (4)]. Idiopathic erythrocytosis was reported in 11 male patients with a history of HBV infection. Patients with the diagnosis of erythrocytosis underwent phlebotomy every 3 weeks until the hematocrit level reached 45%, and this was repeated if the level exceeded 49%, so no patient presented with cardiovascular accidents during the follow-up. In conclusion, a history of HBV infection, male sex, and hepatitis B immune globulin therapy are all possible cofactors for an increased risk of erythrocytosis in OLT patients.

Correlation of viral load with bone marrow and hematological changes in pale patients with chronic hepatitis C virus

Liver is considered the target of hepatitis C virus (HCV), which has marked tropism for hepatocytes. In this study, we investigated changes in bone marrow (BM) and blood and their correlation with viremia level in 30 pale patients with chronic HCV who were selected before antiviral therapy. Patients with BM positive for HCV RNA (53.33 %) showed moderate to high viremia, while patients with BM negative for RNA (46.67 %) had low viremia. There was no significant difference in the liver histopathology between patients with HCV-RNA-negative and positive BM. Patients with BM positive for HCV RNA showed significant changes in BM cells, including the degree of immune complex deposition and alterations in peripheral blood counts compared to patients with BM negative for RNA and healthy controls, suggesting that BM changes could be a sequel or a reservoir for HCV viremia.

Biological and clinical implications of HBV infection in peripheral blood mononuclear cells

The liver is the main site of HBV replication, however extrahepatic organs, such as the lymphoid system, are an important reservoir of the virus. Viral DNA into different mononuclear cell subsets has been mainly detected in monocytes and B lymphocytes. The attachment site of the virus has been identified in the preS1 encoded protein of the virus envelope, the same involved in hepatocyte infection. The risk of HBV transmission by infected lymphocytes has been clearly documented in the setting of liver transplantation where de novo HBV infection has been found in up to about 80% of liver grafts from HBsAg negative but anti-HBc positive donors. In the hemodialysis setting the percentage of HBV DNA detection in mononuclear cells of HBsAg negative patients has been described in up to 54% of the cases. Vertical transmission studies indicate that HBV-infected mononuclear cells of the mother may result in viral infection of mononuclear cells of the newborns and possible HBV vaccine response failure. HBV can also infect bone marrow cells and in vitro studies demonstrate a block of hematopoiesis by HBV, supporting clinical observations of isolate cases of aplastic anemia associated to the infection.

Bone marrow-derived mesenchymal stem cells are capable of mediating hepatitis B virus infection in injured tissues

We have previously showed that endothelial progenitor cells (EPCs) through uptake of hepatitis B virus (HBV) may play a critical role in mediating extrahepatic HBV diseases. However, it remains to be elucidated whether mesenchymal stem cells (MSCs) are capable of mediating HBV trans-infection into extrahepatic tissues.

METHODS AND RESULTS

In this study, we showed that HBV antigens, HBV DNA and the viral particles were detected in MSCs after 3 days virus challenge. Neither HBV covalently closed circular DNA nor pregenomic RNA were detected in MSCs. Intravenously transplantation of HBV-exposed MSCs into myocardial infarction mouse model resulted in incorporation of HBV into injured heart and other damaged tissues.

CONCLUSION

These results indicate that MSCs could serve as an additional extrahepatic virus reservoir, which may play a role at least in part in mediating HBV trans-infection into the injured tissues through the process of MSCs recruitment.

Infection of hepatitis B virus in extrahepatic endothelial tissues mediated by endothelial progenitor cells

Background

Hepatitis B virus (HBV) replication has been reported to be involved in many extrahepatic viral disorders; however, the mechanism by which HBV is trans-infected into extrahepatic tissues such as HBV associated myocarditis remains largely unknown.

Results

In this study, we showed that human cord blood endothelial progenitor cells (EPCs), but not human umbilical vein endothelial cells (HUVECs) could be effectively infected by uptake of HBV in vitro. Exposure of EPCs with HBV resulted in HBV DNA and viral particles were detected in EPCs at day 3 after HBV challenge, which were peaked around day 7 and declined in 3 weeks. Consistently, HBV envelope surface and core antigens were first detected in EPCs at day 3 after virus challenge and were retained to be detectable for 3 weeks. In contrast, HBV covalently closed circular DNA was not detected in EPCs at any time after virus challenge. Intravenous transplantation of HBV-treated EPCs into myocardial infarction and acute renal ischemia mouse model resulted in incorporation of HBV into injured heart, lung, and renal capillary endothelial tissues.

Conclusion

These results strongly support that EPCs serve as virus carrier mediating HBV trans-infection into the injured endothelial tissues. The findings might provide a novel mechanism for HBV-associated myocarditis and other HBV-related extrahepatic diseases as well.

Hepatitis A virus suppresses monocyte-to-macrophage maturation in vitro

To analyze the pathogenetic mechanism of hematopoietic dysregulation associated with hepatitis A virus (HAV) infections, we studied the influence of HAV on monocyte (MO)-to-macrophage (MAC) maturation in vitro. Exposure of peripheral blood-derived mononuclear cells (MNC) to HAV led to diminished adherence of MO to plastic. Furthermore, HAV inhibited the ability of peripheral blood MO to differentiate toward MAC. Freshly isolated and 14-day-old MO cultures demonstrated reduced differentiation and decreased phagocytic capacity after challenge with HAV. Viral replication in MO/MAC cultures was confirmed by titration of infectious virus. We also determined the influence of HAV on the MO/MAC population in human long-term bone marrow cultures (LTBMCs). Inoculation of bone marrow MNC with HAV suppressed the establishment of an adherent stromal layer containing a reduced number of MAC. Furthermore, increased MO numbers in the nonadherent fraction of HAV-challenged LTBMCs are indicative of the disturbance of MO adherence. These findings suggest that HAV infection leads to a disorder of the mononuclear phagocytic system which may contribute to functional abnormalities of the bone marrow stroma.

Hepatitis B virus infection associated with hematopoietic tumors

Hepatitis B virus (HBV) infection and replication have been linked to the development of hepatocellular carcinoma. Bone marrow-derived cells, as well as mesenchymal and epithelial cells, were recently shown to support HBV replication. We hypothesize that the mechanism that links HBV infection and liver tumors might also promote tumor development in tissues permissive for HBV replication. Between 1980 and 1993 we retrospectively identified 22 patients who were hepatitis B surface antigen (HBsAg) carriers and had extra-hepatic malignancies. These patients had 25 tumors, of which 22 were bone marrow derived. HBsAg was detected by immunohistochemistry in bone marrow cells of leukemia patient and of 3 of 10 lymphoma patients. In addition, in 4 of 10 patients with lymphoma, including 2 patients in which HBsAg stained bone marrow cells, HBsAg was also detected in the endothelial cells of blood vessels of the tumor tissue. These results suggest that the identification of an HBV gene product in endothelial cells might point to a role of HBV infection in the development of certain hematopoietic tumors, possibly through activation of cytokines or growth factors, which may eventually lead to bone marrow cell proliferation.