VIRAL AND AUTOIMMUNE HEPATITIS
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 Human Hepatitis Viruses
Virus Genome Genome Envelope Family / genus size (kb) HAV RNA 7.5 - Picornaviridae positive sense , hepatovirus single stranded, linear HBV DNA 3.2 + Hepadnaviridae partially double stranded, circular HCV RNA 9.6 + Flaviviridae positive sense, hepacivirus single stranded, linear HDV RNA 1.7 + Unclassified positive sense, (viroid), delta virus single stranded, linear HEV RNA 7.5 - Unclassified, positive sense, single togavirus and stranded, linear alpha virus-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 HEPATITIS
• Jaundice • Hepatomegaly with RUQ tenderness • Fever – low grade • 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
Hepatitis A Virus
• Nucleic Acid: 7.5 kb ssRNA 27 nm • Classifi ca tion: Picornavi rid ae, 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
5 Global Prevalence of Hepatitis A HAV - Epidemiology Global Prevalence of Hepatitis A Infection
HAV Prevalence High Intermediate Low Very Low
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 Typical Serologic Course of Acute Hepatitis A Virus Infection
Syypmptoms
ALT Total anti-HAV
Fecal HAV IgM anti-HAV
00112233 4455661212 24 Months after exposure
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 Hepatitis B Virus: Morphology and Characteristics Hepatitis B Virus
•Nucleic Acid: 3.2 kb DNA • Classification: Hepadnaviridae • Multiple serotypes and genotypes 42 nm A-F • Enveloped 22 nm • In vitro model: primary hepatocyte culture and HBsAg transfection of cloned HBV DNA
42 nm HBcAg • In vivo replication: in cytoplasm, cccDNA in nucleus; hepatocyte and other tissues, human and HBV DNA other primates
4
Hepatitis B Virus: Viral Replication. Pt. 1 Hepatitis B Virus - Replication
Viral entry
NlNucleus
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 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 inflammatory 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 inflammatory Clearance Direct cells cytotoxicity ? NK, NKT cells
HEPATITIS 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
12 Clinical Significance of Serological Markers for HBV Infection HBV - Diagnosis Serological Clinical Markers Significance HBsAg Acute/Chronic infection Anti-HBc IgM Acute infection HBeAg High infectivity Anti-HBe Low infectivity Anti-HBs Immunity Anti-HBc IgG and HBsAg Chronic infection Anti-HBc IgG and anti-HBs Resolved infection
Serological Markers of Acute HBV Infection HBV - Diagnosis Acute HBV Infection
HBV DNA
HBe Ag AtiAnti-HBe Anti-HBs Anti-HBc
HBsAg Anti-HBc IgM
0 2 4 6 Months Years
13 Hepatitis C Virus: Morphology and Characteristics
Hepatitis C Virus •Nucleic Acid: 9.6 kb ssRNA • Classification: Flaviviridae, Hepacivirus
40-60 nm • 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 C Virus: Genome and Gene Products, pt.2 Hepatitis C Virus Genome and Gene Products
CCE1E1 E2 NS2 NS3 NS4B NS5A NS5B 5’ UTR P7 NS4A 3’ UTR
Structural protein Nonstructural protein coding region coding region
CCE1E1 E2 NS2 NS3 A NS4 B NS5A NS5B Protease Core Protease Cofactor
Envelope Serine Helicase RNA polymerase protease
14 Hepatitis C Virus: The Functions of Gene Products Hepatitis C Virus Gene Products and Functions
Core (C) Nucleocapsid E1 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 CfCofactor for NS3NS 3 protease act iiivity NS 4B Formation of membranous web NS 5A Interferon sensitivity sequence NS 5B RNA-dependent RNA polymerase
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 - HepatitisImmunopathogenesis C Virus - Immunopathogenesis Hepatitis C Virus: Immune Responses and Pathogenesis, pt. 1
HCV 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 inflammatory 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 inflammatory Viral cells Clearance Hepatocytes
Hepatitis C Virus: Immune Responses and Pathogenesis, pt. 5 Hepatitis C Virus - Immunopathogenesis
Cryoglobulins Autoimmunity Antigen presenting Immune cells Lympho- modulation proliferative Ig disorders Lyypmphoid CD4 Class II cells TH HCV B cell Cytokines CD8 Class I CTL
Apoptosis HCV or cytopathic Steatosis replication Cytokines Nonspecific inflammatory Viral cells Clearance NK, Hepatocytes NKT cells
19 HEPATITIS C CLINICAL
• Most common cause of chronic hepatitis in USA • 15%1.5% o f popu la tion in USA carr ies the v irus • 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 Acute HCV Infection 1000 HCV RNA positive 800 AntiAnti--HCVHCV ALT 600 (IU/L) 400 Symptoms
200
Normal 0 ALT 002224446668881010 12 24 1122233344455 6 7 Weeks Months Time After Exposure
Hoofnagle JH, Hepatology 1997; 26:15S
20 Outcome Following Hepatitis C Infection HCV - Natural History Outcome Following Hepatitis C Infection Acute hepatitis C 80% Chronic infection 70% Chronic hepatitis 1 --4%/yr4%/yr 20% HCC Cirrhosis Decompensation Time 4 --5%/yr5%/yr (yr) 10 20 30
HEPATITIS D AND E
• HEPATITIS D – Also kno wn 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
• Elevated liver enzymes (AST and/or ALT) for greater th an 6 month s w ith ch arac teri sti c pathologic findings • Many different diseases can cause chronic hepatitis • Liver biopsy is frequently performed for definitive diagnosis
PATHOLOGY OF CHRONIC HEPATITIS • Portal tracts, peri-portal regions and lobules are ildinvolved • Liver biopsy shows chronic inflammation manifested as increased inflammatory cells - mainly plasma cells and lymphocytes • The inflammation may result in fibrosis which can lead to cirrhosis
22 ETIOLOGY OF CHRONIC LIVER ENZYME ELEVATIONS
• Viral – B and C • Autoimmune • Drugs • Metabolic – Wilson’s
• Fatty liver - Steatohepatitis • Alcohol • Others – CHF, hemochromatosis, ulcerative colitis, celiac disease, and others.
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 (though some patients have normal liver enzymes) – positive serology – positive DNA or RNA in bloo d – diagnostic liver biopsy • Treatment available with varying success rates
23 Serological Markers of Chronic HBV Infection HBV - Diagnosis Chronic HBV Infection HBV DNA
HBeAg Anti-HBe
HBsAg
Anti-HBc IgG
Anti-HBc IgM
Months Years
Serological Markers of Acute HBV Infection HBV - Diagnosis Acute HBV Infection
HBV DNA
HBe Ag AtiAnti-HBe Anti-HBs Anti-HBc
HBsAg Anti-HBc IgM
0 2 4 6 Months Years
24 Dynamics of the different phases of chronic hepatitis B virus (HBV) infection
Wong, S. N. et al. Arch Intern Med 2006;166:9-12.
Copyright restrictions may apply.
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
25 Acute hepatitis C infection HCV - Diagnosis Chronic HCV Infection 1000 HCV RNA positive 800 AntiAnti--HCVHCV ALT 600 (IU/L) 400 Symptoms
200
Normal 0 ALT 002224446668881010 12 24 1122233344455 6 7 Weeks Years Time After Exposure
Hoofnagle JH, Hepatology 1997; 26:15S
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 - thyro id disease, coliti s, h emol yti c anemi a, ITP , diabetes, celiac disease, polymyositis, pericarditis, SLE, MCTD
26 AUTOIMMUNE HEPATITIS
• Clinical presentation – generally female, fatigue, jaundice, hypergammaglobulinemia, elevated AST and ALT • Lab - presence of associated autoantibodies – ANA, thyroid antibodies, LKM, smooth muscle • Diagnostic liver biopsy – interface hepatitis and plasma cell infiltration • Treatment - steroids and immunosuppressants
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