THE CHANGING FACE OF VIRAL

HEPATITISD. Robert Dufour, MD, FACB, FCAP

Consultant PathologistAttending, Liver ClinicVAMC, Washington DC

Emeritus Professorof Pathology

• Acute viral hepatitis has become an increasingly rare disease

• Reported incidences are at their lowest recorded values for all major viruses

• Childhood immunization has led to near universal immunity to HBV in USA

• From this standpoint, we are winning the war against viral hepatitis

SIGNIFICANCE

Source: CDC Viral Hepatitis Surveillance and Statistics

Source: CDC Viral Hepatitis Surveillance and Statistics

Source: CDC Viral Hepatitis Surveillance and Statistics

• Chronic HBV and HCV remain common• In US, chronic HCV affects at least 2% (2.7

million individuals), while chronic HBV affects approximately 1 million (85% born outside US)

• Both may lead to cirrhosis (20-30% after 20 yr), hepatocellular carcinoma (HCC) (3-5%/yr once cirrhosis present)

SIGNIFICANCE

SIGNIFICANCE• Symptoms of chronic infection minimal, most unaware

until complications develop• Cirrhosis expected to increase 4-fold over next 30 years• HCC incidence doubled over past 20 years, expected to

increase further 3x; at VAMC DC, have gone from 5-6/yr to 3-4/month

• Effective therapies available for HBV, HCV

HEPATITIS A, E

HEPATITIS A• Peak age incidence now 20-35

• Major risk factors injection drug use, males having sex with males

• IgM anti-HAV now largely (62%) false positive; CDC recommends use only in clinical setting of acute hepatitis (MMWR 2005;54:453)

HEPATITIS E• Recognized as an enteric virus in locations with poor hygiene;

anti-HEV < 5% in children, but 30-60% in young adults, men > women

• High mortality in pregnant women (30-50%); low mortality rate otherwise (as with HAV)

• As with HAV, thought not to have a chronic phase

• In developed countries, felt to not occur without travel to endemic areas

HEPATITIS E• HEV is endemic in pigs and rats worldwide• Link between pork ingestion, death from chronic liver

disease in 18 countries• Studies have shown high frequency (10-20%) anti-HEV in

blood donors in western countries• Has raised issue of zoonotic spread of HEV, but known cases

of HEV difficult to link to pork ingestion or pig exposure

HEPATITIS E• In past few years, well documented case series of HEV in

Europe with the same genotype as found in animals (J Med Virol 2008;80:646); age range similar but mortality higher (10%), esp. in those with chronic liver disease (70%)

• Anti-HEV more common in IV drug users; post-transfusion cases in several countries

• Recently, reports of chronic HEV in liver transplant recipients (Liv Transpl 2008;14:547)

HEV DIAGNOSIS• IgM anti-HEV best test for acute infection; as with HAV,

false positive possible, may be false negative in early stage

• IgG anti-HEV long-lasting (but probably not life-long); rise in titer can also be used for acute infection diagnosis

• HEV RNA viremia persists for an average of 4 weeks in acute infection; no commercial labs in US currently offer HEV RNA, however

HEPATITIS B

• Partially double-stranded DNA virus, belongs to family hepadnaviridae

• Peculiar pattern of coding, replication unique among viruses

• Virus is not hepatotoxic; damage occurs from T-cell response to the virus

• Virus may be carcinogenic (? Related to HBV X antigen)

HBV BIOLOGY

HBV Replication

Circulating HBV

Infection Reservoir

Replication HBV mRNA

ReverseTranscriptase

RNA-DNA Hybrid

Partially ds-DNA Pre-S

Free HBsAg

Free HBeAg

HBVparticle

RnaseDNA Polymerase

Partially ds-DNA

Covalently ClosedCircular (ccc) DNA

HBV core AgHBVpolymeraseHBV

mRNAHBVmRNA

HBV BIOLOGY• RNA replication leads to high rate of mutations (not as high as

HIV, though)• Certain sites of mutation more common - #1 is stop codon in

pre-core coding region, also commonly affect core promoter region; both decrease production of HBeAg (latter may also increase risk of HCC)

• Mutations commonly induced by some reverse transcriptase inhibitors used to treat virus

OUTCOME• Outcome mainly dependent on age at exposure, less affected

by immune status

• In infants, 95% chronically infected; in young children, 30-50% chronically infected

• In adults and adolescents, HBV is usually “cleared” after exposure, < 5% chronically infected (may be < 1%)

• In immunosuppressed adults and adolescents, 10-20% chronically infected

HBVExposure

HBV Outcomes in Infants and Children < 5

Immune Control

Loss of HBsAgImmune Tolerance

Immune Active

5%

1-2%/yr

95%

50-70% 30-50%

7-8%/yr

0.5-1%/yr

7-8%/yr1-2%/yr

HBVExposure

Outcomes of HBV exposure in Adults

Immune Control

Loss of HBsAgAcute

Hepatitis

Immune Active

10-20% (low immune status)

30-50%50-70%

7-8%/yr

1-2% (normal immune status)

? 0.5%

1%/yr

0.5%/yr

HBV SEROLOGIC TESTS• Complicated set of markers lead to confusing patterns

• Even more complicated by increased knowledge of biology of HBV

• Still most widely used tests for HBV diagnosis, becoming less widely used for monitoring of treatment

HBsAg• Responsible for genotypes of HBV; common “a” determinant in all

genotypes

• Vaccine response mainly to “a” determinant

• Mutants in “a” determinant may not be recognized by vaccine, HBsAg serologic tests

• Multiple mutants occur; none recognized by all current HBsAg test kits

• Little data, but mutants usually occur with wild-type virus, in low amounts, and rare as sole infection

ISOLATED ANTI-HBc• Early in viral clearance (“Core window” in acute hepatitis,

during recovery)

• Many years following infection; especially common in HCV infected

• Failure to develop anti-HBs (?especially in immune deficient)

• False positive result (post-influenza vaccine, other states)

• HBsAg mutants (recent study – 3%)

HBeAg• Produced along with viral particles, but not part of virus; not

needed for replication, function uncertain (? immune response)

• Correlates with replicating virus in untreated; loss usually = low level (or no) viremia

• Not produced by pre-core or core promoter mutants• During treatment, loss indicates likelihood of continued

response after discontinuation

HBV DNA in HBeAg Pos vs Neg

0%

20%

40%

60%

80%

100%

< 2 2 3 4 5 6 > 7

Log HBV DNA (IU/mL)

HBeAg Pos HBeAg neg

Source: VA Medical Center Washington DC

ANTI-HBe• Appears with loss of HBeAg, indicating loss of

circulating virus• Formerly used to indicate transition to carrier state• Also present if HBeAg lost due to development of pre-

core mutant strains• Usually persists for life, but some lose anti-HBe and re-

develop HBeAg (and re-activate HBV DNA production)

HBV DNA• Assays have marked difference in detection limit;

reported in pg/mL, copies/mL (1 pg = 285,000 copies)

• WHO standard now used for most assays (IU/mL), but correlation not linear (unresolved issue)

• Most with chronic hepatitis have > 105 copies/mL (often > 109); levels < 102 thought to have low transmission risk

Lower Detection Limits for HBV DNA

Method Detection Limit IU/mL pg/mL

Hybrid Capture 1.0 * 106 10.5

Branched DNA 2.0 1 * 105 2.5 Liquid Hybridization 4.0 * 103 0.02 Branched DNA 3.0 2.0 * 103 0.01 PCR 1-2 * 102 0.001 Real Time PCR 2-5 * 101 0.0001

HBV OUTCOMES & SEROLOGYState HBsAg Anti-

HBsAnti-HBc

HBeAg Anti-HBe

HBV* DNA

ALT

Acute hepatitis Pos Neg Pos‡ Pos Neg > 106

Immune tolerance

Pos Neg Pos Pos Neg > 106 Nl

Immune active Pos Neg Pos Pos Neg > 106

HBeAg + hepatitis

Pos Neg Pos Neg Pos < 106

Immune control Pos Neg Pos Neg Pos < 102† Nl

Occult Neg Pos Pos Neg Pos < 102† Nl

*In IU/mL; ‡ Typically IgM anti-HBc positive; †May be positive with very sensitive techniques in serum or liver biopsy

HBV REACTIVATION• Return of HBV replication where previously inactive• More common form: HBsAg positive but in immune

control phase, virus again replicative (often with return of HBeAg)

• Less common form: HBsAg negative, anti-HBc positive when viral replication returns (sometimes termed seroreversion)

HBV REACTIVATION• Usually occurs in setting of immune suppression (HIV,

transplant, steroids, cancer chemotherapy); frequency higher with more intense immune suppression

• While viral replication itself, immune response to virus often causes severe liver injury with recovery of immune function

• High morbidity and moratlity

ImmuneSuppression

HBV Reactivation

Immune Control

Anti-HBc posHBsAg neg

Acute Hepatitis

Acute liver failure

30-50%

1-2% 20%

10-20%Restore

Immunity

HBV REACTIVATION• Treatment of HBsAg positive pre-immune

suppression highly effective• Associated with reduced overall and liver-related

mortality• Recent guidelines suggest routine testing for HBsAg

and anti-HBc before immune suppression, treatment if HBsAg positive; less clear for anti-HBc positive

HEPATITIS C

HCV BIOLOGY• Single strand RNA virus, part of flaviridae family

(WNV, yellow fever, dengue)

• Relatively new virus (? Late 1880’s)

• High rate of spontaneous mutation leads to unique pattern of quasispecies in each individual after initial infection

• Virus not cytopathic, destroyed by T-cell response

• Major screening test for HCV, detects antibody to 1 of 4 HCV antigens

• Two basic versions (2nd, 3rd generation) in use; 2nd sl less sensitive, not positive till avg 12 wk after exposure, 3rd sl less specific, pos. avg 9 wk.

• EIA tests less specific than CA, MEIA versions for same generation, but false positive results relatively common with all

ANTI-HCV

ANTI-HCV• Most false positive are weakly positive

• Weak positive defined as 3.8 by EIA, 8 by Ortho, 10 by Abbott, < 11 by Siemens

• Majority of weakly positive are negative on other anti-HCV assays or on confirmatory tests

• CDC recommends performance of RIBA on all weakly positive before reporting

Positives defined by S/C ratio

OR

OR

RIBA for anti-HCV

Screening test for Anti-HCV ReportNegative

Report ReportReport

Positive IndeterminateNegative

HCV RNA

All positives

RIBA for anti-HCV

Report

ReportReport Report

Negative

Positive

IndeterminateNegativePositive

Positive

Report

Positives with high S/C ratio Positives with low S/C ratio

HCV RIBA Equivalent to western blot; uses purified HCV antigens from yeast recombinants

Positive: Ab to at least 2 Ag Indeterminate: Ab to one Ag, or to yeast marker (SOD) plus HCV Ags

Most patients with high titer anti-HCV have positive, usually used only when low titer anti-HCV (or in blood donors)

TREATMENT OF CHRONIC

HBV AND HCV

ACUTE HEPATITIS• No treatment is recommended for acute HBV (except in

rare cases with acute liver failure)• Acute HCV usually not recognized; when diagnosed

(e.g., post-needlestick) several studies suggest that treatment with interferon for 6 months can clear virus in 90-100% of cases, compared to 50% with no treatment

• Treatment effective in first 6 months

• Seven agents approved: interferon (std., pegylated), lamivudine, adefovir, telbivudine, entecavir, tenofovir; last two most used

• Combination treatment not currently used• Response rate to IFN low in those with normal ALT, or viral load <

105 or > 1010 copies/mL• “Ideal” response: nl ALT, loss of HBeAg and HBV DNA, and

development of anti-HBe• Rarely, HBsAg is also cleared

CHRONIC HEPATITIS B

• Histologic improvement usually seen with clearance• Relapses after treatment can occur• Success rate with 1 yr Rx about 30-40%• With oral agents, increasing treatment to 3-4 yrs increases

response to 70%, but resistant mutants also increase (28% with 5 yr treatment for adefovir, 70% for lamivudine, < 5% for entecavir, tenofovir [2 yr data only])

CHRONIC HEPATITIS B

• In HBeAg +, ALT (> 1.5 x nl), or advanced biopsy findings (mod or higher inflammation, stage II or higher fibrosis), esp if > 40 yrs old

• In HBeAg -, similar, but also based on VL (treatment not recommended if < 2000 IU/mL, or if < 20,000 IU/mL and biopsy shows minimal damage), esp. if > 40 yrs old

• Patients not treated should be monitored, as changes in status are common

TREATMENT INDICATIONS

Copyright restrictions may apply.Chen, C.-J. et al. JAMA 2006;295:65-73.

Cumulative Incidence of Hepatocellular Carcinoma by Serum HBV DNA Level at Study Entry

104-105

< 104

105-106

> 106HBsAg pos > 106

105-106

104-105

< 104

HBeAg neg

• In those with cirrhosis, reduces likelihood of complications (including HCC), can delay or eliminate need for transplant

• Histologic improvement (including decreased fibrosis) common with viral response

• Felt to have similar benefits in those with less advanced disease, but long term data lacking (although histologic improvement documented)

TREATMENT BENEFITS

• Loss of HBV DNA (< 100 IU/mL) is achieved in 70-80%; measurable HBV DNA indicates high rate of relapse

• Timing of measurements unclear; one study suggests response highest if < 100 at 12 wk

• If < 2 log decrease by 3 mo, we generally switch to another agent

• If viral load detectable but > 100, we usually continue treatment, re-evaluate at 6 mo

MONITORING Rx

• In HBeAg + with loss HBV DNA, serial monitoring of HBeAg status prognostic; if HBeAg lost (and anti-HBe develops), treatment can be D/C after 6-12 mo with 80% success

• In HBeAg – (or HBeAg + who do not convert), D/C treatment leads to rapid reactivation of HBV replication; treatment usually long-term in these patients

MONITORING Rx

CHRONIC HEPATITIS C• Current treatment of choice is pegylated interferon plus ribavirin

• Treatment usually for 24 wks with genotype 2 or 3, 48 wks for other genotypes

• Goal of treatment is clearance of virus that persists after therapy stopped

• Response rate is about 40% with genotype 1, 70-80% with genotypes 2, 3, 60-70% with genotype 4

CHRONIC HEPATITIS C• Effectiveness monitored at 12 wk; failure to clear virus or

fall by > 2 logs (early virologic response, EVR) indicates < 5% likelihood of success

• Success evaluated 6 mo post-Rx as absent HCV RNA by sensitive method (sustained virologic response, SVR)

• In those with SVR, likelihood of recurrent viremia < 1%; however, virus persists in mononuclear cells in most

CHRONIC HEPATITIS C• Intermediate time points provide additional data and can be used

to customize treatment duration• Rapid virologic response (RVR): absent HCV RNA after 4

weeks of treatment (~90% SVR)• In those still positive at 4 weeks but negative at 8 weeks, 70%

SVR rate• In those with EVR but viral load measurable at 8 wk, longer

treatment (72 wk G1, 48 wk G2/3) improves response rate

RECENT ARTICLES• HBV Guidelines:

– AASLD - Hepatology 2007;45:507– CDC Recommentations: MMWR 2008;57(RR-08)

• HCV Guidelines:– AASLD - Hepatology 2004;39:1147– CDC (on lab testing) MMWR 2003;52 RR-3

• Reactivation Review– Ann Intern Med 2008;148:519

• HEV Review– Lancet Infect Dis 2008;8:698