VIRAL AND AUTOIMMUNE HEPATITIS WHAT IS HEPATITIS? CAUSES OF ACUTE HEPATITIS SYMPTOMS OF ACUTE VIRAL HEPATITIS

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1 VIRAL AND AUTOIMMUNE Arthur M. Magun, M.D. linical Professor of Medicine Human Hepatitis Viruses Human Hepatitis Viruses Virus Genome Genome Envelope Family / genus size (kb) HAV RNA Picornaviridae positive sense, hepatovirus single stranded, linear DNA Hepadnaviridae partially double stranded, d circular RNA Flaviviridae positive sense, hepacivirus single stranded, linear HDV RNA Unclassified positive sense, (viroid), delta virus single stranded, linear HEV RNA Unclassified, positive sense, single togavirus and stranded, linear alpha virus-like WHAT IS? Inflammation of the liver Almost always, inflammation implies elevation in liver enzymes AST and are the key liver enzymes Other Liver Function Tests (LFTs) which can be abnormal in hepatitis include: Bilirubin, albumin, alkaline phosphatase, gamma glutamyl transpeptidase O INFETIOUS ETIOLOGIES OF AUTE MV - cytomegalovirus; immunocompromised host EPSTEIN-BARR mononuclesosis; lymphadenopathy; splenomegaly TB and M. avium intracellurare (MAI) AUSES OF AUTE Viral hepatitis Other infectious etiologies e.g. MV, EBV, TB Alcoholic hepatitis Drug hepatitis Ischemic hepatitis holedocholithiasis SYMPTOMS OF AUTE VIRAL Fatigue, nausea, anorexia Jaundice Low-grade fever, abdominal pain Arthralgia, myalgia, headache 1

2 Hepatitis A Virus: Morphology and haracteristics Global Prevalence of Hepatitis A SIGNS OF AUTE VIRAL Jaundice Hepatomegaly with RUQ tenderness Fever low grade Splenomegaly infrequent 27 nm Hepatitis A Virus Nucleic Acid: 7.5 kb ssrna lassification: Picornaviridae, Hepatovirus One serotype and multiple genotypes Nonenveloped, acid and heat stable In vitro model: monkey and human cell cultures In vivo replication: in cytoplasm of hepatocyte; human and other higher primates LIV BLOOD TEST ABNORMALITIES IN AUTE VIRAL AST AND IU Bilirubin generally elevated both conjugated and unconjugated Alkaline Phosphatase minimally elevated Bilirubin and urobilinogen increased in urine HAV - Epidemiology Global Prevalence of Hepatitis A Infection HAV Prevalence High Intermediate Low Very Low OUTOMES OF VIRAL AUTE ILLNESS HRONI URE FULMINANT A Oral fecal route of transmission Excreted in stool about 2 weeks prior to clinical illness 1 month incubation period hildren often asymptomatic Never causes chronic hepatitis 2

3 HAV Typical Serologic ourse of Acute Hepatitis A Virus Infection Symptoms Serological ourse of Acute Hepatitis A Hepatitis B Virus - Replication Viral entry Hepatitis B Virus: Viral Replication. Pt. 1 Total anti-hav Fecal HAV M anti-hav Nucleus Months after exposure 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 preexposure Vaccine available to induce active immunity Hepatitis B Virus - Replication Viral entry Nuclear import Repair 3.5 kb RNA Hepatitis B Virus: Viral Replication. Pt. 2 cccdna Transcription 2.4/2.1 kb RNA 42 nm 42 nm 22 nm DNA Hepatitis B Virus: Morphology and haracteristics Hepatitis B Virus HBcAg Nucleic Acid: 3.2 kb DNA lassification: Hepadnaviridae Multiple serotypes and genotypes A-F Enveloped In vitro model: primary hepatocyte culture and transfection of cloned DNA In vivo replication: in cytoplasm, cccdna in nucleus; hepatocyte and other tissues, human and other primates Hepatitis B Virus - Replication Viral entry Nuclear import Repair 3.5 kb RNA Hepatitis B Virus: Viral Replication. Pt. 3 cccdna Transcription Positive strand synthesis Removal of pregenome Negative 2.4/2.1 kb RNA strand synthesis Encapsidation 4 3

4 Hepatitis B Virus - Replication Viral entry Nuclear import Repair Hepatitis B Virus: Viral Replication. Pt. 4 Assembly & budding 3.5 kb RNA cccdna Transcription Export Positive strand synthesis Removal of pregenome Negative 2.4/2.1 kb RNA strand synthesis Encapsidation Hepatitis B Virus - Immunopathogenesis Hepatitis B Virus: Immune Responses and Pathogenesis, pt. 3 I Direct cytotoxicity? NK, NKT Hepatitis B Virus: Immune Responses and Pathogenesis, pt. 1 Hepatitis B Virus - Immunopathogenesis Hepatitis B Virus: Immune Responses and Pathogenesis, pt. 4 Hepatitis B Virus - Immunopathogenesis I Apoptosis learance Direct cytotoxicity? NK, NKT Hepatitis B Virus: Immune Responses and Pathogenesis, pt. 2 Hepatitis B Virus - Immunopathogenesis I B VIRUS NATURAL HISTORY 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 4

5 - Diagnosis Serological Markers Anti-HBc M Anti-HBe Anti-HBs Anti-HBc G and Anti-HBc G and anti-hbs linical Significance of Serological Markers for Infection linical Significance Acute/hronic infection Acute infection High infectivity Low infectivity Immunity hronic infection Resolved infection Hepatitis Virus E2 NS2 NS3 NS4B UTR P7 NS4A UTR Structural protein coding region ore Envelope Hepatitis Virus: Genome and Gene Products, pt.2 Genome and Gene Products E2 NS2 Protease Serine protease Nonstructural protein coding region NS3 A NS4 Protease ofactor Helicase B RNA polymerase - Diagnosis Acute Infection DNA Serological Markers of Acute Infection Anti-HBc Anti-HBe Months Anti-HBs Anti-HBc M Years Hepatitis Virus Hepatitis Virus: The Functions of Gene Products Gene Products and Functions ore () Nucleocapsid and E2 Envelope proteins hypervariable region in E2 p7 Nonstructural, ion channel (?) NS 2 NS 2-3 protease NS 3 Protease, nucleotide triphosphatase, and RNA helicase NS 4 ofactor for NS 3 protease activity NS 4B Formation of membranous web NS 5A Interferon sensitivity sequence NS 5B RNA-dependent RNA polymerase nm Hepatitis Virus: Morphology and haracteristics Hepatitis Virus Nucleic Acid: 9.6 kb ssrna lassification: Flaviviridae, Hepacivirus Genotypes: 1 to 6 Enveloped In vitro model: primary hepatocyte and T cell cultures; replicon system In vivo replication: in cytoplasm, hepatocyte and lymphocyte; human and other primates Hepatitis Virus - Replication Entry Lipoproteins Hepatitis Virus: Viral Replication, pt. 1 5

6 Hepatitis Virus - Replication Lipoproteins Hepatitis Virus: Viral Replication, pt. 2 Hepatitis Virus - Hepatitis Immunopathogenesis Virus - Immunopathogenesis Hepatitis Virus: Immune Responses and Pathogenesis, pt. 1 Entry NS4B NS3/4A NS2 haperones Nucleus E2 -E2 Hepatitis Virus - Replication Hepatitis Virus: Viral Replication, pt. 3 Hepatitis Virus: Immune Responses and Pathogenesis, pt. 2 Hepatitis Virus - Immunopathogenesis Lipoproteins Entry Replication + Progeny genome NS4B NS3/4A NS2 haperones Nucleus E2 -E2 I Hepatitis Virus - Replication Entry Lipoproteins Replication + Hepatitis Virus: Viral Replication, pt. 4 Progeny genome NS4B NS3/4A NS2 Assembly haperones Nucleus E2 -E2 -E2 Export Golgi Hepatitis Virus: Immune Responses and Pathogenesis, pt. 3 Hepatitis Virus - Immunopathogenesis I 6

7 Hepatitis Virus: Immune Responses and Pathogenesis, pt. 4 Hepatitis Virus - Immunopathogenesis I - Diagnosis (IU/L) Acute hepatitis infection Acute Infection Symptoms RNA positive Anti- Apoptosis or cytopathic replication Viral learance Steatosis Weeks Months Time After Exposure Hoofnagle JH, Hepatology 1997; 26:15S Normal 7 Hepatitis Virus - Immunopathogenesis ryoglobulins Autoimmunity Immune Lympho- modulation proliferative disorders Lymphoid Apoptosis or cytopathic replication Viral learance Hepatitis Virus: Immune Responses and Pathogenesis, pt. 5 Steatosis I NK, NKT - Natural History Outcome Following Hepatitis Infection Time (yr) Acute hepatitis 80% hronic infection Outcome Following Hepatitis Infection 70% hronic hepatitis 1-4%/yr 20% irrhosis 4-5%/yr H Decompensation LINIAL 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 D AND E D Also known as delta agent Uses the protein coat Hepatitis B must be present coinfection or preexist E Water borne virus resembling hepatitis A Rarely seen in USA 7

8 HRONI Elevated liver enzymes (AST and/or ) for greater than 6 months with characteristic pathologic findings Many different diseases can cause chronic hepatitis Liver biopsy is frequently performed for definitive diagnosis HRONI B AND irrhosis 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 elevations (though some patients have normal liver enzymes) positive serology positive DNA or RNA in blood diagnostic liver biopsy Treatment available with varying success rates PAOLOGY OF HRONI Portal tracts, peri-portal regions and lobules are involved Liver biopsy shows chronic inflammation manifested as increased - mainly plasma and lymphocytes The inflammation may result in fibrosis which can lead to cirrhosis - Diagnosis hronic Infection DNA Serological Markers of hronic Infection Anti-HBc M Anti-HBe Anti-HBc G Months Years ETIOLOGY OF HRONI LIV ENZYME ELEVATIONS Viral B and Autoimmune Drugs Metabolic Wilson s Fatty liver - Steatohepatitis Alcohol Others HF, hemochromatosis, ulcerative colitis, celiac disease, and others. - Diagnosis Acute Infection DNA Serological Markers of Acute Infection Anti-HBc Anti-HBe Months Anti-HBs Anti-HBc M Years 8

9 Dynamics of the different phases of chronic hepatitis B virus () infection AUTOIMMUNE Genetically predisposed host exposed to an environmental agent triggering an autoimmune response directed at liver antigens leading to a necro response Wong, S. N. et al. Arch Intern Med 2006;166:9-12. Associated with other autoimmune diseases - thyroid disease, colitis, hemolytic anemia, ITP, diabetes, celiac disease, polymyositis, pericarditis, SLE, MTD opyright restrictions may apply. Serologic events in infection AUTOIMMUNE anti- HBs Anti- HBe Anti-HBc G anti-hbc M DNA Acute Infection Vaccine Responder Normal Exposure with Immunity / Normal hronic (Wild Type) / N hronic (Precore Mutant) /N linical presentation generally female, fatigue, jaundice, hypergammaglobulinemia, elevated AST and Lab - presence of associated autoantibodies tib ANA, thyroid antibodies, LKM, smooth muscle Diagnostic liver biopsy interface hepatitis and plasma cell infiltration Treatment - steroids and immunosuppressants Inactive arrier /+ Normal - Diagnosis (IU/L) Acute hepatitis infection hronic Infection Symptoms RNA positive Anti- END Weeks Years Time After Exposure Normal 7 Hoofnagle JH, Hepatology 1997; 26:15S 9