VIRAL AND AUTOIMMUNE

Arthur M. Magun, M.D. Clinical Professor of Medicine

WHAT IS HEPATITIS ?

• Inflammation of the liver • Almost always, inflammation implies elevation in liver enzymes • AST and ALT are the key liver enzymes • Other Liver Function Tests (LFTs) which can be abnormal in hepatitis include: • Bilirubin, albumin, alkaline phosphatase, gamma glutamyl transpeptidase

1 CAUSES OF ACUTE HEPATITIS

• Viral hepatitis • Other infectious etiologies e.g. CMV, EBV, TB • Alcoholic hepatitis • Drug hepatitis • Ischemic hepatitis • Choledocholithiasis

Human Hepatitis Viruses HumanHuman HepatitisHepatitis VirusesViruses

VirusVirus Genome Genome Genome Genome Envelope Envelope Family Family // genusgenus sizesize (kb)(kb) HAVHAV RNA RNA 7.5 7.5 - - Picornaviridae Picornaviridae positivepositive sense,sense, hepatovirushepatovirus singlesingle stranded,stranded, linearlinear HBVHBV DNA DNA 3.2 3.2 + + Hepadnaviridae Hepadnaviridae partiallypartially doubledouble stranded,stranded, circularcircular HCVHCV RNA RNA 9.6 9.6 + + Flaviviridae Flaviviridae positivepositive sense,sense, hepacivirushepacivirus singlesingle stranded,stranded, linearlinear HDVHDV RNA RNA 1.7 1.7 ++ UnclassifiedUnclassified positivepositive sense,sense, (viroid),(viroid), deltadelta virusvirus singlesingle stranded,stranded, linearlinear HEVHEV RNA RNA 7.5 7.5 -- Unclassified,Unclassified, positivepositive sense,sense, singlesingle togavirustogavirus andand stranded,stranded, linearlinear alphaalpha virus-likevirus-like

2 OTHER INFECTIOUS ETIOLOGIES OF ACUTE HEPATITIS

• CMV - cytomegalovirus; immunocompromised host • EPSTEIN-BARR – mononuclesosis; lymphadenopathy; splenomegaly • TB and M. avium intracellurare (MAI)

SYMPTOMS OF ACUTE VIRAL HEPATITIS

• Fatigue, nausea, anorexia • Jaundice • Low-grade fever, abdominal pain • Arthralgia, myalgia, headache

3 SIGNS OF ACUTE VIRAL HEPATITS

• Fever – low grade • Jaundice • Hepatomegaly with RUQ tenderness • Splenomegaly - infrequent

LIVER BLOOD TEST ABNORMALITIES IN ACUTE VIRAL HEPATITIS

• AST AND ALT - 1000-5000 IU • Bilirubin – generally elevated – both conjugated and unconjugated • Alkaline Phosphatase – minimally elevated • Bilirubin and urobilinogen increased in urine

4 OUTCOMES OF VIRAL HEPATITIS

ACUTE ILLNESS

CHRONIC HEPATITIS CURE FULMINANT HEPATITIS

Hepatitis A Virus: Morphology and Characteristics

HepatitisHepatitis AA VirusVirus

•• NucleicNucleic Acid:Acid: 7.57.5 kbkb ssRNAssRNA 27 nm •• Classification:Classification: Picornaviridae,Picornaviridae, HepatovirusHepatovirus •• OneOne serotypeserotype andand multiplemultiple genotypesgenotypes •• Nonenveloped,Nonenveloped, acidacid andand heatheat stablestable •• InIn vitrovitro model:model: monkeymonkey andand humanhuman cellcell culturescultures •• InIn vivovivo replicatioreplication:n: inin cytoplasmcytoplasm ofof hepatocyte;hepatocyte; humanhuman andand otherother higherhigher primatesprimates

5 Global Prevalence of Hepatitis A HAV - Epidemiology GlobalGlobal PrevalencePrevalence ofof HepatitisHepatitis AA InfectionInfection

HAVHAV PrevalencePrevalence HighHigh IntermediateIntermediate LowLow VeryVery LowLow

HEPATITIS A

• Oral fecal route of transmission • Excreted in stool about 2 weeks prior to clinical illness • 1 month incubation period • Children often asymptomatic • Never causes chronic hepatitis

6 Serological Course of Acute Hepatitis A HAV TypicalTypical SerologicSerologic CourseCourse ofof AcuteAcute HepatitisHepatitis AA VirusVirus InfectionInfection

Symptoms

ALT ALT TotalTotal anti-HAVanti-HAV

FecalFecal HAVHAV IgMIgM anti-HAV anti-HAV

00 11 22 33 44 55 66 1212 2424 MonthsMonths afterafter exposureexposure

HEPATITIS A PREVENTION AND TREATMENT • No treatment of infection available • Passive immunity with gamma globulin can ameliorate disease in early stages of the infection • Gamma globulin can prevent disease pre- exposure • Vaccine available to induce active immunity

7 Virus: Morphology and Characteristics

HepatitisHepatitis BB VirusVirus

••NucleicNucleic Acid:Acid: 3.23.2 kbkb DNADNA •• Classification:Classification: HepadnaviridaeHepadnaviridae • Multiple serotypes and genotypes 42 nm • Multiple serotypes and genotypes 42 nm A-FA-F •• EnvelopedEnveloped 22 nm 22 nm •• InIn vitrovitro model:model: primaryprimary hepatocytehepatocyte culture culture andand HBsAg transfectiontransfection of of clonedcloned HBVHBV DNADNA

42 nm HBcAg •• InIn vivovivo replication:replication: inin cytoplasm,cytoplasm, cccDNAcccDNA in in nucleus;nucleus; hepatocytehepatocyte andand otherother tissues,tissues, humanhuman andand HBV DNA otherother primatesprimates

4

Hepatitis B Virus: . Pt. 1 - Replication

Viral entry

Nucleus

8 Hepatitis B Virus: Viral Replication. Pt. 2 Hepatitis B Virus - Replication

Viral entry

Uncoating

Nuclear import cccDNA

Repair Transcription

5’ 3’ 2.4/2.1 kb RNA 5’ 3’ 3.5 kb RNA

Hepatitis B Virus: Viral Replication. Pt. 3 Hepatitis B Virus - Replication

Viral entry

Uncoating Positive strand synthesis Nuclear import cccDNA Removal of pregenome Repair Transcription

5’ 3’ Negative 2.4/2.1 kb RNA strand 5’ 3’ Translation synthesis 3.5 kb RNA Encapsidation

9 Hepatitis B Virus: Viral Replication. Pt. 4 Hepatitis B Virus - Replication Export Viral entry

Uncoating Uncoating Assembly ER & budding Positive strand synthesis Nuclear HBsAg import cccDNA Removal of pregenome Repair Transcription

5’ 3’ Negative 2.4/2.1 kb RNA strand 5’ 3’ Translation synthesis 3.5 kb RNA Encapsidation

Hepatitis B Virus: Immune Responses and Pathogenesis, pt. 1 Hepatitis B Virus - Immunopathogenesis

HBV

HBV

Hepatocytes

10 Hepatitis B Virus: Immune Responses and Pathogenesis, pt. 2 Hepatitis B Virus - Immunopathogenesis

HBV TH CD4 Class II Ig Antigen presenting cells

B cell CD8 Class I

CTL

HBV

Hepatocytes

Hepatitis B Virus: Immune Responses and Pathogenesis, pt. 3 Hepatitis B Virus - Immunopathogenesis

HBV TH CD4 Ig Class II Antigen presenting cells Cytokines B cell CD8 Class I

CTL

HBV

Cytokines

Hepatocytes Nonspecific inflammatoryinflammatory Direct cells cytotoxicity ? NK, NKT cells

11 Hepatitis B Virus: Immune Responses and Pathogenesis, pt. 4 Hepatitis B Virus - Immunopathogenesis

HBV TH CD4 Ig Class II Antigen presenting cells Cytokines B cell CD8 Class I

CTL Apoptosis HBV

Cytokines

Hepatocytes Nonspecific inflammatoryinflammatory Clearance Direct cells cytotoxicity ? NK, NKT cells

HEPATITIS B CLINICAL

• Transmission – parenteral, secretions, sexual mother to child (vertical) • 6-8 week incubation • 20% pf patients have serum sickness prodrome • 4% of patients develop chronic hepatitis • Treatment and vaccine available

12 Clinical Significance of Serological Markers for HBV Infection HBV - Diagnosis SerologicalSerological ClinicalClinical MarkersMarkers SignificanceSignificance HBsAgHBsAg Acute/Chronic Acute/Chronic infectioninfection Anti-HBcAnti-HBc IgMIgM Acute Acute infectioninfection HBeAgHBeAg High High infectivityinfectivity Anti-HBeAnti-HBe LowLow infectivityinfectivity Anti-HBsAnti-HBs Immunity Immunity Anti-HBcAnti-HBc IgGIgG and and HBsAgHBsAg Chronic Chronic infectioninfection Anti-HBcAnti-HBc IgGIgG and and anti-Hanti-HBsBs Resolved Resolved infectioninfection

Serological Markers of Acute HBV Infection HBV - Diagnosis AcuteAcute HBVHBV InfectionInfection

HBV DNA

HBeAg Anti-HBeAnti-HBe Anti-HBsAnti-HBs Anti-HBcAnti-HBc

HBsAg Anti-HBcAnti-HBc IgMIgM

00 22 44 6 6 MonthsMonths Years Years

13 Virus: Morphology and Characteristics

HepatitisHepatitis CC VirusVirus ••NucleicNucleic Acid:Acid: 9.69.6 kbkb ssRNAssRNA •• Classification:Classification: Flaviviridae,Flaviviridae, HepacivirusHepacivirus

40-60 nm •• Genotypes:Genotypes: 11 toto 66 •• EnvelopedEnveloped •• InIn vitrovitro model:model: primaryprimary hepatocytehepatocyte and and TT cellcell cultures;cultures; repliconreplicon system system •• InIn vivovivo replicatioreplication:n: inin cytoplasm,cytoplasm, hepatocytehepatocyte and and lymphocyte;lymphocyte; humanhuman andand otherother primatesprimates

Hepatitis C Virus: Genome and Gene Products, pt.2 Hepatitis C Virus GenomeGenome andand GeneGene ProductsProducts CC E1E1 E2E2 NS2NS2 NS3NS3 NS4BNS4B NS5ANS5A NS5BNS5B 5’ UTR 5’ UTR P7P7 NS4ANS4A 3’3’ UTRUTR

StructuralStructural proteinprotein NonstructuralNonstructural proteinprotein codingcoding regionregion codingcoding regionregion

CC E1E1 E2E2 NS2NS2 NS3NS3 AA NS4NS4 BB NS5ANS5A NS5BNS5B ProteaseProtease CoreCore ProteaseProtease CofactorCofactor

Serine EnvelopeEnvelope Serine HelicaseHelicase RNARNA polymerasepolymerase proteaseprotease

14 Hepatitis C Virus: The Functions of Gene Products Hepatitis C Virus GeneGene ProductsProducts andand FunctionsFunctions

CoreCore (C)(C)Nucleocapsid Nucleocapsid E1E1 andand E2E2Envelope Envelope proteinsproteins hypervariablehypervariable region region inin E2E2 p7p7Nonstructural, Nonstructural, ionion channelchannel (?)(?) NSNS 22NS NS 2-32-3 proteaseprotease NSNS 33Protease, Protease, nucleotidnucleotidee triphosphatase,triphosphatase, andand RNARNA helicasehelicase NSNS 44Cofactor Cofactor forfor NSNS 33 proteaseprotease activityactivity NSNS 4B4BFormation ofof membranousmembranous webweb NSNS 5A5AInterferon sensitivitysensitivity sequencesequence NSNS 5B5BRNA-dependent RNA-dependent RNARNA polymerasepolymerase

Hepatitis C Virus: Viral Replication, pt. 1 Hepatitis C Virus - Replication

Lipoproteins

Entry

15 Hepatitis C Virus: Viral Replication, pt. 2 Hepatitis C Virus - Replication

Lipoproteins

Entry

NS5B NS4B NS5A NS3/4A ER C NS2 E1 Uncoating E2 Chaperones ER E1-E2 Translation Nucleus

Hepatitis C Virus: Viral Replication, pt. 3 Hepatitis C Virus - Replication

Lipoproteins

Progeny genome Entry Replication +

NS5B NS4B NS5A NS3/4A ER C NS2 E1 Uncoating E2 Chaperones ER E1-E2 Translation Nucleus

16 Hepatitis C Virus: Viral Replication, pt. 4 Hepatitis C Virus - Replication

Lipoproteins

Export Progeny genome Entry Replication Assembly + E1-E2

NS5B NS4B Golgi NS5A NS3/4A ER C NS2 E1 Uncoating E2 Chaperones ER E1-E2 Translation Nucleus

Hepatitis C Virus: Immune Responses and Pathogenesis, pt. 1 Hepatitis C Virus - Immunopathogenesis

HCV

HCV

Hepatocytes

17 Hepatitis C Virus: Immune Responses and Pathogenesis, pt. 2 Hepatitis C Virus - Immunopathogenesis Antigen presenting cells

Ig CD4 Class II TH HCV B cell Cytokines CD8 Class I CTL

HCV

Hepatocytes

Hepatitis C Virus: Immune Responses and Pathogenesis, pt. 3 Hepatitis C Virus - Immunopathogenesis Antigen presenting cells

Ig CD4 Class II TH HCV B cell Cytokines CD8 Class I CTL

HCV

Cytokines Nonspecific inflammatoryinflammatory cells Hepatocytes

18 Hepatitis C Virus: Immune Responses and Pathogenesis, pt. 4 Hepatitis C Virus - Immunopathogenesis Antigen presenting cells

Ig CD4 Class II TH HCV B cell Cytokines CD8 Class I CTL

Apoptosis HCV or cytopathic Steatosis replication Cytokines Nonspecific inflammatoryinflammatory Viral cells Clearance Hepatocytes

Hepatitis C Virus: Immune Responses and Pathogenesis, pt. 5 Hepatitis C Virus - Immunopathogenesis

Cryoglobulins Autoimmunity Antigen presenting ImmuneImmune cells Lympho- modulation proliferative Ig disorders Lymphoid CD4 Class II cells TH HCV B cell Cytokines CD8 Class I CTL

Apoptosis HCV or cytopathic Steatosis replication Cytokines Nonspecific inflammatoryinflammatory Viral cells Clearance NK, Hepatocytes NKT cells

19 HEPATITIS C CLINICAL

• Most common cause of chronic hepatitis in USA • 1.5% of population in USA carries the virus • Parenteral transmission – blood, sexual • 6-8 week incubation period • Acute infection generally mild • 80% of acute develop chronic disease • No vaccine available • Treatment – 40-80% cure rate

Acute hepatitis C infection HCV - Diagnosis AcuteAcute HCVHCV InfectionInfection 1000 HCV RNA positive 800 Anti-HCV 600 ALTALT 600 (IU/L) (IU/L) Symptoms 400

200

NormalNormal 0 ALTALT 0 2 4 6 8 10 12 24 1 2 3 4 5 6 7 WeeksWeeks MonthsMonths TimeTime AfterAfter ExposureExposure

HoofnagleHoofnagleJH, JH, HepatologyHepatology 1997;1997; 26:15S26:15S

20 Outcome Following Hepatitis C Infection HCV - Natural History OutcomeOutcome FollowingFollowing HepatitisHepatitis CC InfectionInfection Acute hepatitis C 80%80% Chronic infection

70%70% Chronic hepatitis 11 - 4%/yr 20%20% HCC Cirrhosis Decompensation 4 - 5%/yr TimeTime 4 - 5%/yr (yr)(yr) 10 20 30

HEPATITIS D AND E

• HEPATITIS D – Also known as delta agent – Uses the HBsAg protein coat – Hepatitis B must be present – coinfection or preexist

• HEPATITIS E – Water borne virus resembling hepatitis A – Rarely seen in USA

21 CHRONIC HEPATITIS

• Fatty liver • Viral – B and C • Autoimmune •Drugs • Alcohol • Metabolic • Others – CHF, hemochromatosis, vasculitis, IBD, celiac disease, neoplasia, etc.

CHRONIC HEPATITIS B AND C

• Cirrhosis develops in 20% of patients • Liver failure and hepatoma develop in about ½ of cirrhotics • Diagnosis of chronic hepatitis made on basis of: – chronic AST and ALT elevations – positive serology – positive DNA or RNA in blood – some patients have normal liver enzymes • Treatment available with varying success rates

22 Serological Markers of Chronic HBV Infection HBV - Diagnosis ChronicChronic HBVHBV InfectionInfection HBV DNA

HBeAg Anti-HBeAnti-HBe

HBsAgHBsAg

Anti-HBc IgG

Anti-HBc IgM

MonthsMonths YearsYears

Serologic events in HBV infection

anti- Anti- Anti-HBc anti-HBc HBV HBsAg HBs HBeAg Hbe IgG IgM DNA ALT

Acute HBV Infection + - + - + + + ↑↑

Vaccine Responder - + - - - - - Normal Exposure with Immunity - + - +/- + - - Normal Chronic HBV (Wild Type) + - + - + - + ↑ / N Chronic HBV (Precore Mutant) + - - + + - + ↑ /N

Inactive Carrier + - - + + - -/+ Normal

23 Acute hepatitis C infection HCV - Diagnosis ChronicChronic HCVHCV InfectionInfection 1000 HCV RNA positive 800 Anti-HCV 600 ALTALT 600 (IU/L) (IU/L) Symptoms 400

200

NormalNormal 0 ALTALT 0 2 4 6 8 10 12 24 1 2 3 4 5 6 7 WeeksWeeks YearsYears TimeTime AfterAfter ExposureExposure

HoofnagleHoofnagleJH, JH, HepatologyHepatology 1997;1997; 26:15S26:15S

AUTOIMMUNE HEPATITIS

• Genetically predisposed host exposed to an environmental agent triggering an autoimmune response directed at liver antigens leading to a necroinflammatory response

• Associated with other autoimmune diseases - thyroid disease, colitis, hemolytic anemia, ITP, diabetes, celiac disease, polymyositis, pericarditis, SLE, MCTD

24 AUTOIMMUNE HEPATITIS

• Clinical presentation – generally female, fatigue, jaundice, hypergammaglobulinemia, elevated AST and ALT • Presence of associated autoantibodies – ANA, thyroid antiboides, LKM, smooth muscle • Diagnostic liver biopsy – interface hepatitis and plasma cell infiltration • Treatment - steroids and immunosuppressants

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