Viral pathogens

Viral dynamic modelling of Hepatitis C and resistance-associated variants in haemophiliacs

AIM

Chronic hepatitis C virus (HCV) infection is an important source of morbidity and mortality among haemophiliacs. Limited data are available regarding treatment intervention using direct-acting antivirals (DAAs) and theoretical concerns regarding accumulation of drug-associated resistance variants (RAVs) remain. We conducted a pilot study of treatment with telaprevir/pegylated interferon-alfa/ribavirin to evaluate treatment response and the role of lead-in DAA therapy on mutational selection of resistance variants.

METHODS

Ultra-deep sequence analysis was performed at baseline, 48 hours and 168 hours after treatment initiation.

RESULTS

No dominant RAVs were identified at baseline, but low-level RAVs were noted at baseline in all subjects. Viral dynamic models were used to assess treatment responses. The efficacy parameter (Ɛ) for lead-in ranged from 0 to 0.9745 (mean = 0.514). Subsequent addition of telaprevir resulted in a mean efficacy of more than 0.999. This was comparable to subjects who started all three medications simultaneously. A total of 80% achieved SVR. While rapid shifts in the RAV population following DAA initiation were observed, treatment failure associated with A156V was observed in only one patient. Adverse event profiles were similar to that observed in non-haemophilia cohorts. There was no evidence of factor inhibitor formation. There was no evidence that lead-in provided benefit in terms of response efficacy.

CONCLUSION

These data support DAA-based therapy in those with inherited bleeding disorders.

Current concepts in the prevention of pathogen transmission via blood/plasma-derived products for bleeding disorders

The pathogen safety of blood/plasma-derived products has historically been a subject of significant concern to the medical community. Measures such as donor selection and blood screening have contributed to increase the safety of these products, but pathogen transmission does still occur. Reasons for this include lack of sensitivity/specificity of current screening methods, lack of reliable screening tests for some pathogens (e.g. prions) and the fact that many potentially harmful infectious agents are not routinely screened for. Methods for the purification/inactivation of blood/plasma-derived products have been developed in order to further reduce the residual risk, but low concentrations of pathogens do not necessarily imply a low level of risk for the patient and so the overall challenge of minimising risk remains. This review aims to discuss the variable level of pathogenic risk and describes the current screening methods used to prevent/detect the presence of pathogens in blood/plasma-derived products.

Detection of Parvovirus B19 Infection in Thalasemic Patients in Isfahan Province, Iran

BACKGROUND

Parvovirus B19, a member of the Erythrovirus genus of Parvoviridae family, causes various clinical illnesses including infectious erythema, arthropathy, hydrops fetalis or congenital anemia, and transient aplastic crises. The B19 virus can be transmitted through respiratory secretions, blood products, and blood transfusion.

OBJECTIVES

The aim of this study was to detect the B19 virus in thalassemia patients in Isfahan, Iran.

PATIENTS AND METHODS

The prevalence of parvovirus B19 infection was compared between thalassemia major patients and healthy subjects. Plasma samples were collected from 30 thalassemia patients from Isfahan, Iran. Thirty patients without any blood complications were considered as the control group. After DNA extraction from the plasma samples, polymerase chain reaction was performed for parvovirus B19 detection.

RESULTS

The parvovirus B19-specific nucleotide sequence was detected in 6 patients (20%). None of the samples obtained from the 30 control subjects tested positive for B19.

CONCLUSIONS

In this study B19-Parvovirus infection were detected in patients with hematologic disorders in comparison with control subjects. Screening of patients with a high risk of parvovirus B19 infection can considerably reduce the incidence and prevalence of B19 infection.

Hepatitis C virus long-term persistence in peripheral blood mononuclear cells in patients with haemophilia. Detection of occult genotype 1

Peripheral blood mononuclear cells (PBMC) from chronic hepatitis C virus-infected persons can harbour viral variants that are not detected in plasma samples. We explored the presence and persistence of HCV genotypes in plasma and PBMC cultures from 25 HCV-monoinfected and 25 HIV/HCV-coinfected patients with haemophilia. Cell cultures were performed at different time points between 1993 and 2010-2011, and the HCV genome was examined in culture supernatants. Sequential plasma samples were studied during the same time period. Analysing sequential plasma samples, 21% of patients had mixed-genotype infections, while 50% had mixed infections determined from PBMC culture supernatants. HIV coinfection was significantly associated with the presence of mixed infections (OR = 4.57, P = 0.02; 95% CI = 1.38-15.1). In our previous study, genotype 1 was found in 72% of 288 patients of this cohort. Similar results were obtained with the sequential plasma samples included in this study, 69% had genotype 1. However, when taking into account plasma samples and the results from PBMC supernatants, genotype 1 was identified in 94% of the population. The PBMC-associated variants persisted for 10 years in some subjects, emphasizing their role as long-term reservoirs. The presence of genotype 1 in PBMC may be associated with therapeutic failure and should not be disregarded when treating haemophilic patients who have been infected by contaminated factor concentrates. The clinical implications of persistent lymphotropic HCV variants deserve further examination among multiple exposed groups of HCV-infected patients.

Biological therapies for inherited diseases: social and bioethical considerations. Hemophilia as an example

INTRODUCTION

In hemophilia, advanced therapies are warranted from a conceptual and methodological standpoint. Current advanced therapy strategies are centered on the use of adeno-associated viral vectors, although problems related to immunogenicity and hepatotoxicity still remain.

AREAS COVERED

Future clinical trials will have to scrupulously observe international bioethical standards in terms of patient selection, particularly children. Patient recruitment rates are likely to remain low due to the stringent exclusion criteria usually imposed on the trial population regarding their hepatic and immunological markers and the presence of viral coinfection; and to the existence of an optimal palliative treatment.

EXPERT OPINION

Accordingly, the results obtained are likely to be of low statistical significance, which could hinder their application to clinical practice. Another important issue is the degree to which society embraces these new emerging therapies. The unfamiliarity of society with these new methods, together with the many unresolved questions about them that remain, may threaten their acceptance not only by society at large but also by health-care professionals, which would limit their translational application to clinical practice.

The aging patient with hemophilia

The prospects for many boys born with hemophilia today include a normal life expectancy and minimal to no joint disease. However, despite the availability of safe replacement clotting factor concentrates and effective antiviral treatment, the aging patient with hemophilia today faces many challenges. These include management of their hemophilia as well as the same age-related health issues as experienced in the general population. While increasing, data on the prevalence of comorbidities and their management in the hemophilia population remain limited. This review will focus on issues related to management of hemophilia and complications of cardiovascular, musculoskeletal, hepatic, and renal disease. Available research is summarized and potential approaches to management are discussed.

Intrafamilial transmission of hepatitis C virus in patients with severe haemophilia A

The history behind the production of clotting factor concentrates produced differences in the prevalence of Hepatitis C Virus (HCV) and other blood-borne infections in haemophilic patients. Prevalence rates of HCV infection up to 100% were reported in patients treated with concentrates before 1985. Conversely, nowadays, viral inactivation and recombinant technologies have effectively prevented transfusion-transmitted viral pathogens. Recently, new HCV infections in three young brothers were observed. In the absence of any other risk of transmission, their HIV/HCV coinfected uncle, who was living in the same house, was subject to study. Plasma samples of the four relatives were investigated in order to test whether the infections have a common source. A phylogenetic approach using the most variable (E2) viral sequences was carried out using samples from the four family members. The HCV sequences from the study resulted highly related, being those obtained from the uncle the most ancestral ones. Because of the chronological order in which the infections occurred and the relatedness of the sequences, an infection from the uncle to his nephews is the most likely explanation. Special cares must be applied in the case of household contact among members of a family with inherited bleeding disorders.

Serological study on parvovirus B19 infection in multitransfused thalassemia major patients and its transmission through donor units

Background:

Human parvovirus B19 (B19) virus is a newly recognized agent for transfusion transmitted diseases. Beta-thalassemia major patients receive a hypertransfusion regimen, hence, are prone to acquire B19 infection; moreover, B19 escapes viral inactivation methods and donor units are not tested for B19, but there are just a couple of studies globally and none from the Asian continent. Hence, a study was designed to find the frequency of B19 infection and its transmission in multitransfused thalassemia patients.

Materials and Methods:

Ninety multitransfused beta-thalassemia major (thalassemia) patients, 32 controls (age, sex matched) without any history of transfusion were enrolled. Besides the donor units were tested in B19 un-infected patients. B19 specific IgG and IgM antibodies in the sera were analyzed by ELISA (in-house), using B19 VPI and VP2 recombinant and purified antigens; additionally HBsAg and anti-HIV and anti-HCV antibodies were tested for coexisting infections.

Results:

Seventy-three (81%) thalassemia patients tested positive for anti-B19 IgG antibodies as compared to seven (21%) in the controls group (P < 0.01), while anti-B19 IgM antibodies were detected in 37 (41.1%) compared to two (6.2%) in the controls (P < 0.01). Mean age of the thalassemia patient was eight years (range 2 – 18 years) and B19 infection was highest in the six-to-ten year range. Seropositivity increased with the number of transfusions. Two of the four HBsAg positive and five of the seven anti-HCV IgM antibody-positive patients also had anti-B19 IgM. After a six-month follow-up, four (25%) of the 16 seronegative patients seroconverted and anti-B19 IgM antibodies were detected in their donor units.

Conclusions:

Most of multitransfused thalassemics were B19 seropositive or had anti-B19 IgM; in the remaining uninfected group, B19 got transmitted through infected / IgM-positive donor units.

Impact of HIV on liver fibrosis in men with hepatitis C infection and haemophilia

Hepatitis C virus (HCV) is the major cause of liver disease in haemophilia. Few data exist on the proportion with liver fibrosis in this group after long-term HCV and HIV co-infection. We conducted a cross-sectional multi-centre study to determine the impact of HIV on the prevalence and risk factors for fibrosis in haemophilic men with chronic hepatitis C. Biopsies were independently scored by Ishak, Metavir and Knodell systems. Variables were tested for associations with fibrosis using logistic regression and receiver operating curves (ROC). Of 220 biopsied HCV(+) men, 23.6% had Metavir ≥ F3 fibrosis, with higher mean Metavir fibrosis scores among HIV/HCV co-infected than HCV mono-infected, 1.6 vs. 1.3 (P = 0.044). Variables significantly associated with fibrosis included AST, ALT, APRI score (AST/ULN × 100/platelet × 10(9) /L), alpha-fetoprotein (all P < 0.0001), platelets (P = 0.0003) and ferritin (P = 0.0008). In multiple logistic regression of serum markers, alpha-fetoprotein, APRI and ALT were significantly associated with ≥ F3 fibrosis [AUROC = 0.77 (95% CI 0.69, 0.86)]. Alpha-fetoprotein, APRI and ferritin were significant in HIV(-) [AUROC = 0.82 (95% CI 0.72, 0.92)], and alpha-fetoprotein and platelets in HIV(+) [AUROC = 0.77 (95% CI 0.65, 0.88]. In a multivariable model of demographic and clinical variables, transformed (natural logarithm) of alpha-fetoprotein (P = 0.0003), age (P = 0.006) and HCV treatment (P = 0.027) were significantly associated with fibrosis. Nearly one-fourth of haemophilic men have Metavir ≥ 3 fibrosis. The odds for developing fibrosis are increased in those with elevated alpha-fetoprotein, increasing age and past HCV treatment.

The Aging Patient with Hemophilia: Complications, Comorbidities, and Management Issues

Improvements in hemophilia care and antiviral treatments have resulted in increases in median life expectancy for persons with congenital hemophilia A and B. Currently, 2% of hemophilia A and B patients surveyed in US comprehensive hemophilia treatment centers are 65 years of age or older and 15% are 45 years or older. Many of the complications of hemophilia, including intracranial hemorrhage, joint disease, and inhibitor development, increase with increasing age. Hepatocellular carcinoma and end-stage liver disease are increasing in the older hemophilia population due to infection with hepatitis C (HCV) and HCV/HIV coinfection. Older hemophilia patients also now face the same medical conditions associated with aging in the general population, including cardiovascular disease and cancer. Complex hemostatic management, sometimes in conjunction with antithrombotic management, with extensive cross-specialty clinical and laboratory coordination may be required for the care of the older hemophilia patient. Because elderly hemophilia patients currently represent a small portion of the overall hemophilia population, there is little in the way of clinical data to guide recommendations. Registry databases and cooperative group studies are needed for the development of evidence-based guidelines for the older hemophilia population, which is anticipated to expand in the future.