Hepatitis B. Hepatitis Viruses. Hepatitis Viruses. Hepatitis Viruses

Transcription

1 Hepatitis Viruses Hepatitis B History and Overview of Hepatitis B Testing in Australia Hepatitis A Hepatitis B Hepatitis C Hepatitis D Hepatitis E Cytomegalovirus Epstein-Barr Virus Hepatitis Viruses Hepatitis A Hepatitis B Hepatitis C Hepatitis D Hepatitis E Cytomegalovirus Epstein-Barr Virus Hepatitis Viruses Hepatitis A Hepatitis B Hepatitis C Hepatitis D Hepatitis E Cytomegalovirus Epstein-Barr Virus

2 Hepatitis Viruses Hepatitis A Hepatitis B Hepatitis C Hepatitis D Hepatitis E Cytomegalovirus Epstein-Barr Virus Hepatitis Viruses Hepatitis A Hepatitis B Hepatitis C Hepatitis D Hepatitis E Cytomegalovirus Epstein-Barr Virus Q Fever, Leptospirosis, etc Acute Viral Hepatitis Symptoms Fatigue Joint and muscle pain Nausea Fever Diarrhoea Jaundice 20% Abnormal LFTs: ALT, AST > ALP Symptoms distinctive for viral hepatitis Differentiated by Serology

3 Hepatitis B History Recognised around 400BC 1885: Lurman described epidemic: 1,289 vaccinated with smallpox vaccine prepared from human lymph fluid. 191 contracted serum hepatitis. Early 20 th C - Infectious agent: Associated with contaminated needles and syringes, blood products. Transmission experiments during WWII. Differentiated Hepatitis B from Hepatitis A. Hepatitis B History 1965: Baruch Blumberg discovered Australia antigen in the blood of an Australian aboriginal Later known as Hepatitis B surface Antigen () Ouchterlony Double diffusion Ab Ag Hepatitis B History 1965: Baruch Blumberg discovered Australia antigen in the blood of an Australian aboriginal Later known as 1970: Dane discovered the virus particle by EM 42nm complete viral particle (10 6 partilcles/ml) 22mm small spherical particles 22nm filaments () Self assembling into VLPs Up to 300ug/mL Member of Hepadnaviridae family Partially double stranded circular DNA virus

4 Hepatitis B Genome Dane Particle Timeline for Assay Development HBcAg DNA Polymerase AUS-tect Gel diffusion DNA pol ds-dna HBcAg HBcAg HBeAg Genome sequenced in Open Reading Frames Overlapping genes 4 Genes Surface (S) Polymerase Core codes core and HBeAg Regulatory (X) Chen, W N, Oon, C J FEBS Letters (1999) Hunt et al, Hepatology, 31, 5, (2000) Lee, W M, The New England Journal of Medicine, 337, 24, (1997) Timeline for Assay Development Timeline for Assay Development AUS-tect Gel diffusion AUS-tect Gel diffusion CIEP CIEP Welcome Hepatest

5 Timeline for Assay Development Timeline for Assay Development AUS-tect Gel diffusion AUSRIA -125 RIA AUS-tect Gel diffusion AUSRIA -125 RIA Auszyme EIA CIEP Welcome Hepatest CIEP Welcome Hepatest Timeline for Assay Development Timeline for Assay Development AUS-tect Gel diffusion AUSRIA -125 RIA Auszyme EIA AUS-tect Gel diffusion AUSRIA -125 RIA Auszyme EIA HIV HCV CIEP Welcome Hepatest Multiple EIAs CIEP Welcome Hepatest Multiple EIAs

6 Timeline for Assay Development Timeline for Assay Development AUS-tect Gel diffusion AUSRIA -125 RIA Auszyme EIA IMx Assay AUS-tect Gel diffusion AUSRIA -125 RIA Auszyme EIA IMx Assay AxSYM & PRISM HIV HCV HIV HCV CIEP Welcome Hepatest Multiple EIAs Roche Cobas Core II CIEP Welcome Hepatest Multiple EIAs Roche Cobas Core II Access Timeline for Assay Development Timeline for Assay Development AUS-tect Gel diffusion AUSRIA -125 RIA Auszyme EIA IMx Assay AxSYM & PRISM AUS-tect Gel diffusion AUSRIA -125 RIA Auszyme EIA IMx Assay AxSYM & PRISM Abbott Architect HIV HCV HIV HCV CIEP Welcome Hepatest Multiple EIAs Roche Cobas Core II Ortho Vitros CIEP Welcome Hepatest Multiple EIAs Roche Cobas Core II Vitros Roche Elecsys Immulite ADVIA Centaur Access Access

7 Timeline for Assay Development Timeline for Assay Development AUS-tect Gel diffusion AUSRIA -125 RIA Auszyme EIA IMx & PRISM Assay AxSYM & PRISM Abbott Architect AUS-tect Gel diffusion AUSRIA -125 RIA Auszyme EIA IMx & PRISM Assay AxSYM & PRISM Abbott Architect HIV HCV HIV HCV CIEP Welcome Hepatest Multiple EIAs Roche Cobas Core II Vitros Roche Elecsys Immulite ADVIA Centaur CIEP Welcome Hepatest Multiple EIAs Roche Cobas Core II Vitros Roche Elecsys Immulite ADVIA Centaur Access Access HBV Prevalence 350 Million cases worldwide HBV Epidemiology 350 million HBV carriers worldwide. 5% of the world population. Endemic in Africa, South America and particularly SE Asia. World Hepatitis Day: 28 th July Estimated 520 million people are infected with hepatitis B or C 30 million (25%) are in SE Asia (excluding China). At least 170,000 people in Australia are HBV positive. Most are from immigrants from Asia-Pacific region Represents two thirds of Australia s immigrants Chronically infected during childbirth The prevalence of HBV varies from as low as 0.01% - 0.1% in developed countries, to 20% or higher in some developing countries. Hep B vaccination in Australia - acute infection rarely seen. Incident cases: 245 in 2008 New notifications: 7000

8 National Hepatitis B Strategy China and Vietnam have the most HBV cases. High national prevalence High migrant numbers Asia-Pacific region contributes approx 5% of the Australian population Make up 50% of Australians with chronic hepatitis B Hepatitis B Virus Permucosal Sexually transmitted disease Perinatal - vertical transmission Most common cause of chronic HBV Percutaneous IV drug use Most common cause of acute HBV Unsterile tattooing and piercing Unsterile cultural practices (cutting / piercing) Needle stick, body fluid exposure - rare Liver Transplant - rare Hepatitis B Incubation: days % Adults: Uncomplicated acute infection / HBVDNA persist for short period Clearance of virus and seroconversion to anti-hbs. 75% asymptomatic Chronic infection Adults 5-10% Children 30% Infants 90% 25% of Chronic Disease Cirrhosis 1% Hepatocellular Carcinoma

9 Hepatitis B Incubation: days % Adults: Uncomplicated acute infection / HBVDNA persist for short period Clearance of virus and seroconversion to anti-hbs. 75% asymptomatic Chronic infection Adults 5-10% Hepatitis C: 85% Children 30% Infants 90% 25% of Chronic Disease Cirrhosis 1% Hepatocellular Carcinoma Exposure to HBV Outcome of Adult Infection with HBV Acute Infection 95% 5% Chronic Infection Asymptomatic (75%) Symptomatic (25%) Cirrhosis (25%) Healthy Carrier (75%)? Recovery and Immunity Fulminant Hepatitis (~1%) Hepatocellular Carcinoma (~1%) Acute Hepatitis B Symptoms CIRRHOSIS Flu-like symptoms Fever, fatigue, nausea, vomiting Joint and muscle pain Weight loss Jaundice, abnormal LFTs: ALT, AST > ALP Intolerance of alcohol RUQ pain, hepatomegaly Systemic symptoms Vasculitis, glomerulonephritis Fulminant hepatitic failure Dramatic immune response Necrosis of hepatocytes Raised prothrombin time, reduced clotting factors and HBeAg may be negative HEPATOCELLULAR CARCINOMA Hepatocellular carcinoma following chronic viral hepatitis Macronodular cirrhosis following chronic hepatitis B infection.

10 HBV Markers Hepatitis B surface Antigen anti-hbs Acute HBV Infection Hepatitis B core antigen Hepatitis B e Antigen Hepatitis B DNA HBcAg (not circulating) anti-hbc anti-hbc IgM HBeAg anti-hbe HBV DNA Acute HBV Infection Past HBV Infection

11 Chronic HBV Infection Chronic HBV Infection Defined as HBV infection > 6 months. Due to failure of the immune response to eradicate the virus. Host immune response determines outcome and liver injury. 1. Immune tolerance HBeAg positive, high HBV DNA levels, normal ALT levels Minimal liver injury - may persist for decades 2. Immune clearance (competence) Immune response to the virus Cytotoxic Liver injury High ALT levels & fibrosis of the liver. Seroconversion of HBeAg to anti-hbe, reduced viral load. 3. Immune control Inactive carriers - minimal liver inflammation HBV DNA is low and LFTs are normal Only 2% develop HBV reactivation + ALT flares. Chronic HBV infection may last years to decades HBeAg will seroconvert to anti-hbe in inactive phase 4. Immune escape (HBeAg negative chronic hepatitis B) Pre-core mutants High viral load (HBV DNA > 2000 IU/mL) Active disease increased ALT, rapid progression of liver damage HBV Serology Profiles Current HBV Infection : Reactive anti-hbs : <10 IU/L anti-hbcore : Reactive anti-hbc (IgM) : Reactive / Non reactive (acute / chronic) HBeAg : Reactive / Non reactive (active / inactive) HBV Serology Profiles Current HBV Infection - Acute

12 Interpretation of HBV Profiles Past Infection : Non reactive anti-hbs : >10 IU/L anti-hbcore : Reactive Interpretation of HBV Profiles Core Only Positive : Non reactive anti-hbs : <10 IU/L anti-hbc : Reactive Negative and anti-hbs No sero-conversion of to anti-hbs Core only Window Period Interpretation of HBV Profiles Core Only Positive : Non reactive anti-hbs : <10 IU/L anti-hbc : Reactive anti-hbc IgM : Reactive / Non-reactive anti-hbc IgM Reactive = Recent infection Window period Patient should be considered infectious Non reactive = Past HBV and loss of anti-hbs (Confirm a-hbe) False positive anti-hbc Occult HBV infection (Confirm with HBV DNA) and anti-hbs : Negative Anti-HBc IgG/IgM : Positive Occult HBV Presence of HBV DNA with no detectable

13 Case 1 Initial Presentation Case 1 Confirmatory Assay Date Day 0 (Architect) REACTIVE S/CO 855 (Vidas) REACTIVE HBsAb <10 Anti-HBc Non reactive Anti-HBc IgM HBeAg Anti-HBe Non reactive REACTIVE Non reactive NH 25 years old female Routine screening Correctional Centre Clinically well (>50% Neutralisation = Positive) VIDAS Neg Serum Anti-HBs % Neut 307 rfu 8 rfu 98 % Neutralised by confirmatory assay. Reported as a Reactive Interpreted as POSITIVE for Case 1 Day 5 Date Day 0 Day 5 RE RE HBsAb <10 <10 Anti-HBc NR NR Anti-HBc IgM NR NR HBeAg RE RE Anti-HBe NR NR HBV DNA 2.9x10 5 ALT (<40) Case 1 - Day 20 Date Day 0 Day 5 Day 20 RE RE RE HBsAb <10 <10 <10 Anti-HBc NR NR RE Anti-HBc IgM NR NR RE HBeAg RE RE NR Anti-HBe NR NR RE HBV DNA 2.9x10 5 ALT (<40) 10

14 Case 1 - Day 40 Date Day 0 Day 5 Day 20 Day 40 RE RE RE NR HBsAb <10 <10 <10 28 Anti-HBc NR NR RE RE Anti-HBc IgM NR NR RE RE HBeAg RE RE NR NR Anti-HBe NR NR RE RE HBV DNA 2.9x10 5 Case 1 - Conclusions Acute Hepatitis B Infection Rare occurrence Subclinical presentation Normal liver function Resolved spontaneously within 40 days ALT (<40) Case 2 HBV Infection Case 2 HBV Infection Date Apr 09 RE Anti-HBs <10 Anti-HBc RE 36 yo female Elevated LFT s Hx IV drug use Date Apr 09 RE Anti-HBs <10 Anti-HBc RE Anti-HBc IgM RE Anti-HBc IgM RE HBeAg RE HBeAg RE Anti-HBe NR Anti-HBe NR Acute Hepatitis B infection Acute Hepatitis B infection

15 Case 2 HBV Infection Case 2 HBV Infection Date Apr 09 Oct 09 R R HBsAb <10 <10 Anti-HBc R R Anti-HBc IgM R R HBeAg R R Anti-HBe NR NR Date Apr 09 Oct 09 Dec 10 R R R HBsAb <10 <10 <10 Anti-HBc R R R Anti-HBc IgM R R NR HBeAg R R NR Anti-HBe NR NR R Chronic Hepatitis B infection Chronic Hepatitis B infection Loss of HBeAg Case 2 HBV Infection Persistence of >6 months Chronic Disease HBeAg is a marker of viral replication Seroconversion to anti-hbe good prognostic indicator Viral flares can occur: Increased HBV DNA Associated with raised LFT (ALT) Reversion to HBeAg Ongoing liver damage Case 3 HBV Screen 78 year old female Routine screening - Dialysis Patient Date 4/2/2010 Result Neut (Arch) Reactive S/CO: % (Vidas) Reactive TV: % Anti-HBs <10 Anti-HBc NR? Early acute infection

16 Case 3 - Conclusion Case 3 - Report HBV vaccine given 24 hours prior to test Assay detects circulating vaccine Recommendation to ward: Wait 2 weeks after vaccination before testing 54 years old female CML Headache, seizures Hx of BMT in 2002 Case 4 History CMV reactivation retinitis GVHD skin, GIT, and lungs Case 4 - History 19/06/2005: admitted Urea and Creatinine raised LFT normal Pancytopenia 24/06/2005 ALP started to rise 28/06/2005 ALP, GGT, AST, ALT sig elevated

17 Case 4 - Results Date 30/6/05 REACTIVE HBsAb <10 IU/L Anti-HBc Non reactive Anti-HBc IgM Non reactive HBeAg REACTIVE Anti-HBe Non reactive HBV DNA >2X10 5 Case 4 - Results Date 30/11/02 7/11/03 30/6/05 NR NR RE Anti-HBs 269 <10 Anti-HBc RE NR Anti-HBc IgM NR HBeAg RE Anti-HBe NR HBV DNA <300 <300 >2X10 5 Case 4 - Conclusions Previous Hepatitis B infection Recovered, seroconverted Latent HBV DNA remains in hepatacytes Immunosuppression reactivation of HBV Reduced lymphocytes inability to produce antibodies Case 4 - Conclusions Occult Hepatitis B infection Presence of HBV DNA with no detectable anti-hbc +/- anti-hbs anti-hbc contraindicated in Liver Transplantation Reduced immune function Immunosuppressive therapy Chemotherapy

18 Hepatitis B Genome Dane Particle HBV Life Cycle DNA HBcAg ds-dna DNA Polymerase HBcAg HBcAg, HBeAg Genome sequenced in Open Reading Frames 4 Genes Surface (S) Polymerase Core codes core and HBeAg Regulatory (X) Overlapping genes Chen, W N, Oon, C J FEBS Letters (1999) Hunt et al, Hepatology, 31, 5, (2000) Lee, W M, The New England Journal of Medicine, 337, 24, (1997) covalently closed circular DNA Ganem, D., and Prince, A., NEJMed: (2004) Reverse transcriptase: Poor transcription fidelity, error rate of 10 7 nucleotide/day HBV Replication cccdna Complex intra-nuclear replication cycle Forms nuclear covalently closed circular DNA Transcription of mrna (host cell polymerase) 1. mrna translated into proteins in the ER 2. Pre-genomic RNA template for making ve strand DNA Uses HBV RT no proofreading prone to mutation Poor transcription fidelity, error rate of nucleotide/day Makes +ve strand DNA (Genomic DNA) Proteins mrna Core, S proteins RNA HBV Polymerase Host Polymerase Pre-genomic RNA HBV Reverse Transcriptase -ve DNA Most errors will produce non-viable virus May also produce virus with advantages Will proliferate under selective pressure Virion Formation Export Packaging +ve DNA Genomic ds DNA

19 HBV Mutants Pre-core mutants Basal Core Promoter (BCP) Mutations Polymerase (YMDD) Mutants Lamivudine Resistance Mutants Vaccine escape mutants a determinant mutations S gene mutations Pre-Core Mutants Core Ag: produced by core region HBeAg: produced by full length of pre-core and core region. HBcAg, HBeAg Pre-core Mutants Start codon P1 produces HBeAg Single point mutation G1896A causes substitution of Guanine to Adenine Changes TGG to a TAG stop codon in the pre-core region - hence HBeAg will not be produced Start codon P2 downstream from the mutation produces full length HBcore antigen and allows for functional virus Causes HBeAg negative chronic hepatitis B with increased HBV DNA production. Mutants Envelope protein Vaccine escape mutants a determinant mutations S gene mutations P2 X P1 More severe disease G1896A

20 The a Determinant Antigenicity dependant on tertiary structure (conformational loop) Also dependant on adjacent epitopes Tertiary structure determined by cystine residues Mutations around the a determinant may result in changed antigenicity of the protein What are Mutants Mutation between aa 121 and 149 will cause a significant change in antigenicity Most common mutants cluster near aa Usually due to a single point mutation in the S gene gly-145-arg (G145A) is the most common mutation Cause failure of the vaccine produced antibodies to neutralise the mutants Surface antigen escape mutants Vaccine escape mutants can infect vaccinated individuals. These may become the dominant quasi-species Due to immune selection of escape mutants Increased vaccine failure in infants born to positive mothers. 10 years post introduction of universal vaccination at birth in Taiwan 1984: 7.8% 1989: 19.6% 1994: 28.1% Mutations occurring at younger ages Surface antigen escape mutants Vaccination First commercial vaccine (1981): inactivated virus particles from pooled positive serum (formaldehyde and heat treatment) Discontinued in 1990 Recombinant vaccine was available in 1986 Produced against small polypeptide from a determinant mutations - reduced binding to vaccine derived antibodies Can be infected by vaccine escape HBV mutants Targeted vaccination in risk populations since Universal vaccination of infants in Australia since Poor vaccination in adolescents and adults in at-risk groups. Orthotopic Liver Transplant patients treated with HBIG (8.3 to 57%).

21 Case 5 - History JT 75 years old male Renal Dialysis Abnormal LFTs ALT 78 AST 46 ALP 129 GGT 78 Bilirubin 9 Fever Case 5 Results AxSYM RE S/CO: Vidas RE TV: HBsAb 113 IU/L Anti-HBc RE Anti-HBc IgM NR HBeAg NR Anti-HBe RE HBV DNA >1.5x10 5 Case 5 Anomaly 1 AxSYM RE S/CO: AxSYM Vidas RE TV: HBsAb 113 IU/L 1. Anti-HBs in presence of a. Vaccine escape mutant b. Ag:Ab binding anomalies Case 5 AxSYM Neutralisation (>50% = Positive) AxSYM Dilution Neg Serum Anti-HBs %Neut Neat % 1: % NOT neutralised by AxSYM confirmatory assay Result could be a. Reported as a Non-specific reaction and b. Interpreted as NEGATIVE for

22 Case 5 Confirmatory tests Neutralisation (>50% = Positive) Platform %Neut Result AxSYM 29.0 Not Confirmed VIDAS 99.7 Confirmed PRISM 25.0 Not Confirmed Architect 60.0 Confirmed Centaur (2004 version) Not Detected Neutralised Results would be: Reported as a Confirmed and Interpreted as POSITIVE for Case 5 HBV DNA Sequencing Numerous mutations Q101H P120Q E164G S113A P135L V190A S117R Y134S I226N Mutations between aa 121 and 149 will cause a change in antigenicity P120Q documented to cause binding Kfoury, Baz et al 2001 Transfusion Medicine 11: P120Q Case 5 HBV DNA Sequencing HBeAg Anti-HBe Case 5 Anomaly 2 NR RE HBV DNA >1.5x Negative HBeAg in presence of HBV DNA HBeAg: Indicator of viral replication HBV DNA: Presence of viral DNA = replication Patient has Pre-core mutation G1896A Stops production of HBeAg Often leads to more severe disease

23 Mutants Formation Implications to Testing Some mutants will not be detected by all assays. Mutation The a determinant 160 Some mab assays use epitopes in the aa region Change in the protein/epitope structure a determinant gly-145-arg MAb will not recognize / bind to epitope Mutations: Change in nucleic acid-base Natural occurrence Amino acid change in protein Causes: Selective pressure by: Vaccination HBIg therapy Assay may not detect presence of Produces False Negative Chen et al Proc. Natl. Acad. Sci. 93: Reference: Hunt, C.M. et al Clinical Relevance of Hepatitis B Viral Mutations. Hepatology 31: The a determinant Implications to Testing Some mutants will not be detected by all assays. 160 Some mab assays have epitopes in the aa region Monoclonal Choices - Design Control. Avoid monoclonal antibodies against epitopes with high mutation rates Change in the protein/epitope structure Use multiple monoclonals or polyclonal antibodies for capture and detection. MAb will not recognize / bind to epitope All current immunoassays use multiple monoclonal antibodies False negative results 1. Complicate the diagnosis of HBV 2. Delay treatment options 3. Effect safety of the blood supply. Assay may not detect presence of Produces False Negative Reference: Hunt, C.M. et al Clinical Relevance of Hepatitis B Viral Mutations. Hepatology 31:

24 Case 6 - Patient Br 58 year old male Caucasian (resident of PNG) Liver transplant in 1999 : Negative anti-hbs >1000 miu/ml. anti-hbc Negative 6 months post Tx: anti-hbs = 294 miu/ml. Case 6 - Patient Br 58 year old male Caucasian (resident of PNG) Liver transplant in 1999 : Negative anti-hbs >1000 miu/ml. anti-hbc Negative 6 months post Tx: anti-hbs = 294 miu/ml. Acquired HBV infection sometime in 2000 in New Guinea Positive anti-hbc IgM Positive HBeAg Positive Case 6 - Patient Br 58 year old male Caucasian (resident of PNG) Liver transplant in 1999 : Negative anti-hbs >1000 miu/ml. anti-hbc Negative 6 months post Tx: anti-hbs = 294 miu/ml. Acquired HBV infection sometime in 2000 in New Guinea Positive anti-hbc IgM Positive HBeAg Positive Developed shingles, ulcerative colitis, malaria and CMV. Commenced lamivudine and HBIG treatment for HBV infection : HBV DNA: > 2.0 x 10 5 copies/ml Case 6 - Patient Br 58 year old male Caucasian (resident of PNG) Liver transplant in 1999 : Negative anti-hbs >1000 miu/ml. anti-hbc Negative 6 months post Tx: anti-hbs = 294 miu/ml. Acquired HBV infection sometime in 2000 in New Guinea Positive anti-hbc IgM Positive HBeAg Positive Developed shingles, ulcerative colitis, malaria and CMV. Commenced lamivudine and HBIG treatment for HBV infection : HBV DNA: > 2.0 x 10 5 copies/ml Multiple mutations Lamivudine resistance: mutations in polymerase M204V and L180M. mutations: notably G145R. Pre-core mutation.

25 Case 6 - Patient Br Case 6 - Patient Br AxSYM Architect Centaur VIDAS (2004 version) S/CO Positive % Neut % 85 T118M Mutations: Polymerase Pre-core G145R A7V G1896A T118M N123H E164D R153Q I195M V173L L180M M204V Case 7 - Patient NG 66 year old male Migrant from Vietnam Post renal transplant August 2008 Diffuse large B-cell lymphoma Mildly abnormal liver function tests ALP 312 U/L GGT 285 U/L ALT 54 U/L AST 100 U/L No detectable HBeAg Reactive HBV DNA was detected 2.8 x 10 3 IU/mL Treated with lamivudine reduced levels of DNA Anti- HBs Anti- HBc HBeAg NR 159 R R HBV DNA Quant HBV DNA Qual Case 7 - Patient NG Platform result Abbott AxSYM NR S/CO = 0.21 Abbott Architect NR S/CO = 0.01 biomerieux VIDAS NR TV = 0.01 Roche Elecsys NR S/CO = 0.42 Immunolite 2000 NR S/CO = 0.60 Abbott PRISM NR S/CO = 0.19 Vitros ECi NR S/CO = 0.18 Advia Centaur NR Index = < NR R 2.8 X NR 136 R R NR 1000 R R <29 Det

26 Loop 1 sg119r sq129q/r sg130k/r/e sp135t Case 7 - Patient NG negative HBV infection 1. Vaccine escape mutant Not detected by all immunoassays 2. Occult HBV infection negative or below limit of detection Loop 1 aa 107 to 138 (diagnostic antibodies bind) Loop 2 aa 139 to 150 (vaccine/hbig anti-hbs bind) Loss of reactivity in the diagnostic assay due to changes in loop 1 Mutants Summary 1. mutants result from HBV replication errors and selection by selective pressure 2. There is wide geographic prevalence of mutants 3. Assays must be evaluated to determine their ability to detect common mutants (aa epitope) 4. As mutants increase in prevalence so does the challenge to HBV treatment and diagnosis Risk of false negative results Risk of treatment failure 5. Future assays and vaccines need to consider emerging mutations Beware of Mutants

27 Conclusions Most HBV profiles HBV can be easily categorised: Acute Chronic Past Core-only Abnormal HBV profiles require further investigation Consider: Clinical history Other HBV markers HBV DNA, Sequencing Limitations of the testing procedure Treatment transfusion, IgG, vaccination Other Laboratory findings LFTs, etc NFI: Conclusions Refer for second opinion Request follow-up serology Thank-you Case 3 HBV Screening Date 30/6/010 Architect Vidas HBsAb Anti-HBc REACTIVE S/CO = 3.25 Non reactive <10 IU/L Non reactive

28 Case 3 Confirmatory Assay Case 3 Report (>50% Neutralisation = Positive) Architect Neg Serum Anti-HBs % Neut rfu % NOT Neutralised by confirmatory assay. Reported as a Non-specific reaction Interpreted as NEGATIVE for