8. PATHOGENESIS
Determinants of persistence of HCV include
(1) Evasion of immune responses through several viral mechanisms
(2) Inadequate induction of the innate immune response
(3) Insufficient induction or maintenance of an adaptive immune response
(4) Production of viral quasispecies
(5) Induction of immunologic tolerance or exhaustion
9. Entry into the cell
Identification by the host cell and differentiates from self
Activation of cytokines and interferons
CD4 T helper cell
HCV specific CD8+ cytotoxic t cell
Cell injury
10. • In chronic infection – Defect in cd4 proliferation
Decrease cd4 response
Mutation of cd8+ cytotoxic t cell
Upregulation of the inhibitory receptor of functionally exhausted
T cell
• Inhibition of type IFN – Inhibition of IFN signaling and effector cascade
• Intrahepatic and Peripheral NK cell cytotoxicity – Dysfunctional
• C protein, NS 4B, NS 5B – Suppress immunoregulatory NF kappa B – increase TNF
mediated cell death
• Autoimmune hepatitis in subset – cross reactivity between viral antigen and autoantigen
host cell
16. Whom To Test
These focus or priority populations for testing will include but not limited to:
1. People who inject drugs ( PWID)
2. Men who have sex with men
3. Female sex workers
4. People who received blood transfusion before routine testing for hepatitis C
5. People who need frequent blood transfusion, such as, thalassemic and dialysis patients
6. People living with HIV
7. Inmates of prisons and other closed settings
17.
18. • Screening : Detection of antibodies against the antigen
• Most specific : HCV RNA
Detect up to 5 IU/ml
• Probe assay : Detect HCV virus in the peripheral lymphocyte
• Liver enzymes
• Antibodies : anti LKM 1
• Biopsy : paucity of inflammation, marked increase in the sinusoidal lining cells,
lymphoid aggregates , the presence of fat, occasionally bile duct lesion in which biliary
epithelial cell appears to pile up without interruption of basement membrane
19. HCV Genotype
• Identifying the genotype and subtype of HCV is important because some DAA
regimens are only recommended for certain HCV genotypes and subtypes.
• Sofosbuvir/Ledipasvir – ineffective against genotype 2 and 3
• Genotype 1-6 – major
• Minor Genotype 7
• Most common world – 1 subtype a
• Most common in India – 3
21. DRUGS
• Interferon – pegylated interferon alpha 2b and alpha 2a
• Nucleoside analogue
• Protease Inhibitors
• DAA – Direct Acting Antiviral combination therapy
a) Contemporary
b) Future directed
22.
23.
24.
25.
26.
27. Management of Cirrhotic Patients after HCV clearance in
SVR 12
• HCV infection can be considered cured in non-cirrhotic patients who have
achieved a SVR 12 after 12 weeks of completing the treatment. Thus no follow-up
is required.
• Patients with a history of excessive alcohol drinking, obesity, type 2 diabetes,
hypertension etc. should be periodically subjected to a thorough clinical assessment
as needed.
• In patients with cirrhosis who have achieved cured (successful treatment), there is a
persistence of risk of developing HCC Thus, HCC surveillance in these patients
must be indefinite.
28. • These patients with liver cirrhosis who have achieved SVR should remain under
surveillance for HCC every 6 months by ultrasound, and for oesophageal varices by
endoscopy if varices were present at pre-treatment endoscopy.
29. Persons with HIV/HCV Co-infection
• Rapid progression of liver fibrosis, especially those with a CD4 cell count of <200
cells/mm3.
• Patients in whom ART leads to successful control of HIV infection (i.e. undetectable
HIV viral load), the risk of hepatic decompensation among co-infected patients is higher
than among patients with HCV mono infection.
• For these reasons, all persons with HIV/HCV co-infection should be considered for HCV
treatment.
30. Treatment of HIV and HCV Co-infection
• In the past, treatment of HIV and HCV co-infected persons with interferon and
ribavirin combination therapy was difficult, as many patients had to discontinue
treatment due to side-effects such as depression or weight loss as well as severe
anaemia, thrombocytopenia and neutropenia.
• DAA therapy has substantially simplified the treatment of persons with HIV and HCV
co-infection.
• There are fewer Drug-Drug Interactions (DDIs) between DAAs and ARV medicines,
and SVR rates with DAAbased therapy among persons with HIV co-infection are
higher than 95%, even for those with prior HCV treatment failure or advanced
fibrosis.
31. • It is advisable to first initiate treatment for HIV and achieve HIV suppression before
starting HCV treatment, although there are some circumstances where it may make sense
to treat
• HCV infection first and then initiate therapy for HIV -- This could include persons with
moderate-to-severe fibrosis at risk of rapid liver disease progression if the HIV infection is
not associated with significant immunosuppression at the time of treatment.
• ALT and AST should be monitored at 1 month after ART initiation and then every 3–6
months. A significant elevation of AST/ALT should prompt careful evaluation for other
causes of liver function impairment (e.g. alcoholic hepatitis, hepatobiliary disease), and
may require short-term interruption of the ART regimen or specific drug suspected of
causing the elevation
32.
33. Persons with chronic kidney disease
• There is an unmet need for DAA treatment in patients with severe renal disease (eGFR
<30 mL/min/1.73 m2) and those requiring haemodialysis.
• Sofosbuvir, which is used in many approved regimens, does not have the safety and
efficacy data to support its use in these situations.
• Patients receiving ARV drugs in combination with tenofovir and sofosbuvir may require
enhanced renal monitoring.
• Elbasvir/grazoperavir and paritaprevir/ritonavir and dasabuvir – promising results
34. Persons with HBV/HCV co-infection
• Check for the presence of HBV infection before starting HCV treatment.
• HBV and HCV co-infection may result in an accelerated disease course; HCV is
considered to be the main driver of disease.
• Persons co-infected with HBV and HCV can be treated with antiviral therapy for
HCV; SVR rates are likely to be similar to those in HCV-mono infected persons.
• During treatment and after HCV clearance, there is a risk of reactivation of
HBV, and this may require treatment with concurrent anti-HBV antiviral
therapy.
35. Persons with TB/HCV co-infection
• People at increased risk of infection with HCV are also often at increased risk of
infection with TB. Therefore, screening for active TB should be part of the clinical
evaluation of patients being considered for HCV treatment.
• Most of the DAAs interact with metabolic pathways in the liver, which increases
and/or decreases the drug level of DAAs when co-administered with antimicrobial
medicines such as rifabutin, rifampin and rifapentine.
• Therefore, concurrent treatment of HCV infection and TB should be avoided.
• Active TB should generally be treated before commencing therapy for HCV.
36. • Concurrent treatment of HCV infection and multidrug-resistant TB is particularly
complicated because of many DDIs between DAAs and second-line antimicrobials.
37. Women of child-bearing age
• None of the DAAs have been evaluated among pregnant women.
• Thus, women with childbearing potential should be counseled that they require effective
contraception during treatment and for six months after completion of therapy.
• Safety of DAAs in pregnancy has not been established.
• Ribavirin - fetal abnormalities.
• DAAs are thus contraindicated in pregnant women and those with child bearing
potential unless effective contraception (i.e. two forms of contraception) can be
guaranteed during treatment and, for women taking ribavirin, for 6months after
completing therapy.
• Pre-treatment pregnancy tests should be conducted prior to treatment initiation.