Challenges in HBV detec1on in blood donors

Transcription

1 Challenges in HBV detec1on in blood donors Jean- Pierre Allain Dept Haematology, University of Cambridge, UK

2 Phylogene1c analysis of human and ape HBV over 1me of evolu1on (Pareskevis et al, Hepatology 2012) Time (years) 2

3 HBV genotypes & recombinant forms A2/A1 A2 D C/D CRF A/D A3/E CRF F/H D/E CRF B/C E A1 A1/D A2 3 3

4 Recovering HBV infection 1st WP HBV DNA HBsAg 2d WP Anti- HBc 1-2% OBI Anti- HBs Horizontally or vertically transmitted HBV infection HBsAg Anti- HBc HBV DNA Limit of HBsAg detection OBI days years

5 HBsAg- HBV DNA correla1on during the window period Biswas, Transfusion Minegishi, Vox Sanguinis copies or 300 IU/ml HBsAg PRISM S/CO (0.1 IU/ml)

6 Rela1onship between HBsAg and HBV DNA levels (Allain, 2015) HBsAg (log IU/ml) A1 R2=0.02 HBsAg (log IU/ml) A2 R2=0.08 HBsAg (log IU/ml) B R2= HBV DNA (log IU/ml) HBV DNA (log IU/ml) HBV DNA (log IU/ml) n=43 n=72 n=126 6 C 6 D 6 E HBsAg (log IU/ml) R2=0.31 HBsAg (log IU/ml) R2=0.17 HBsAg (log IU/ml) R2= HBV DNA (log IU/ml) HBV DNA (log IU/ml) HBV DNA (log IU/ml) n=90 n=465 n=184

7 HBV viral markers according to genotype HBsAg+/DNA- HBsAg+/DNA+ HBsAg-/DNA+ Spain gt A2/D % N = 211 Ghana gt E 6 85% 9% N = % Taiwan gt B/C N = 133

8 Efficacy of HBV screening assays (Allain unpublished) Type HBV infec=on HBsAg An=- HBc NAT* Window period No No Yes Primary OBI No No Yes 2d WP No Yes Yes Chronic Yes Yes Yes An1- HBc+ OBI No Yes Yes An1- HBs only OBI No No Yes Chronic NAT- Yes Yes No * Depends ID vs MP and assay 8

9 Qual Quant

10 Distribution of HBV serological markers in blood donors from endemic countries JE Levi, Sao Paulo; S Ranganathan, India; T Ahsraf, Muskat, Oman; S El Siddig, Khartoum, Sudan

11 % discarded dona1ons according to tes1ng strategy Country Strategy 1 (an1- HBc+) 2 (an1- HBs- ) 3 (sab 100 IU/L) Brazil India Oman Sudan

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13 Frequency of HBV DNA yield in blood dona1ons (Allain, ISBT 2012) Asia Europe Africa An1- HBc tested Yield HBV DNA in donations India 3 Indonesia India 2 Oman Iran 1 Pakistan India 1 Iran 2 China 4 China 1 Ghana Taiwan 2 Taiwan 1 Thailand 1 China 3 Burma India 4 Spain2 India 5 China 5 Country-study Thailand 2 Italy2 China 2 Korea Poland Spain1 Spain 3 South Africa Italy3 Italy1 Canada China 6 Germany 11 USA

14 Confirmation of viral nucleic acid presence Repeat NAT (Poisson distribution) Alternative NAT - Commercial NAT discriminatory or diagnostic assays - In-house or commercial real-time q-pcr (viral load) - In-house amplification (PCR/nested-PCR) and sequencing Virus concentration before NAT - Increase NA extraction volumes - Centrifugation 10,000g for 60 min - Immuno-capture Any of these procedures positive: viral DNA/RNA confirmed 14

15 HBV DNA screening in high prevalence areas Country N samples HBV DNA Window Occult tested confirmed period HBV Hong Kong 357, (1:3,971) 6 84 Malaysia 108,813 8 (1:13,600) 0 8 Singapore 270, (1:22,575) 0 12 Taiwan 21, (1:880) 1 23 Thailand 486, (1:11,588) 4 38 Italy 271, (1:10,450) 0 26 Poland 250, (1:12,509) 3 17 Spain 516, (1:13,595) 5 33 South Africa 732, (1:11,820) Total 3,015, (1:9,365) 45 (14) 277 (86) USA ARC 3,690,000 9 (1:410,000) 3-4 5

16 Impact of assay sensi1vity on HBV DNA yield Tsoi et al. Transfusion 2013; Vermeulen et al. Transfusion 2014 Country HBV DNA Ultrio Ultrio Plus Times yield LOD 13 IU/ml LOD 3 IU/ml increased yield Egypt WP 1:67,976 1:39, F Moftah OBI 1:8,122 1:1, Genotype D all 1:7,220 1:1, South Africa WP 1:25,120 1:10, M Vermeulen OBI 1:709 1:4, Genotype A1 all 1:5,535 1:3, Hong Kong WP 1:39,755 1:21, CK Lin OBI 1:5,120 1:2, Genotypes B&C all 1:4,536 1:2,

17 45 Distribution of HBV DNA load in SE Asian donors N = 143 % of total NAT sensitivity 5 IU/mL Pools of 6 Pools of % -87.5% <5 2 to 9 10 to to to to to to to to to >1000 Viral load (IU/mL)

18 OBI according to genotype Candoj et al. J Hepatol 2008;49:537 - Allain et al. Hepatology 2009;90: Candoj et al. Gut 2012;61:1744 Europe Far East Asia Africa Genotype A2 D B C A1 E N samples Gender M % NA Median age ALT level <40 <45 <35 <45 <40 <40 % anti-hbs

19 Viral load of 276 OBIs according to genotype Candoj et al. J Hepatol 2008;49:537; Allain et al. Hepatology 2009;90:1868; Candoj et al. Gut 2012;61: N = A1 A2 B C D E Genotype 14

20 Fluctuation overtime of HBV DNA load in blood donors with OBI (Candotti et al Gut 2012; 61:1744) Group 2 (52%) HBV DNA load (logiu/ml) Group 1 (48%) Time (months) 20

21 HBV DNA+ yield cases diagnostic Allain JP, Candotti D, Blood Transfusion 2009; 7: Assay Result HBsAg Positive Negative HBV DNA Positive Negative Anti-HBc Positive Negative Anti HBs Positive Negative Positive Negative Classification OBI (40) OBI (40) OBI (10) WP (10) primary OBI 21 19

22 Diagnosis of confirmed HBV DNA Index sample Alt HBsAg anti-hbc anti-hbs Interpretation Chronic infection low/variant HBsAg OBI OBI persistent recovered Primary OBI, WP, Contamination Follow-up sample DNA HBsAg anti-hbc anti-hbs Interpretation Window period d window period/primary OBI d window period/primary OBI Fluctuating DNA OBI Fluctuating DNA OBI False positive

23 Mechanisms of OBI Muta1ons inducing a defect in produc1on, excre1on and detec1on of S protein/hbsag are a major cause of OBIs Some muta1ons lead to changes in RNA folding interfering with S mrna splicing that plays a role in HBsAg produc1on The amino acid subs1tu1ons accumulated in the S protein MHR and extra MHR domains interfere with: Viral replica1on S protein produc1on and export HBsAg detec1on The humoral and/or cellular immune system fail controlling HBV infec1on

24 Puta1ve structure of S protein in lipid membrane (Jeantet, Hepatology 2002; Biswas et al. J Virol 2013) HBsAg 178R 75T 32 24

25 Molecular characterisation of HBsAg mutations (El Chaar et al. Hepatology 2010;52: ) HBsAg assays 25

26 Distribu1on of serological HBV markers in 2028 vaccinated blood donors age (Zheng et al. Transfusion 2014) 100% 90% 80% 70% % of total 60% 50% 40% 30% 20% 10% 0% Age (years) An1- HBs- an1- HBc+ An1- HBs+ an1- HBc+ An1- HBs+ an1- HBc- An1- HBs- an1hbc 26 -

27 Hypothetical summary of HBV infection in HBV vaccinated Chinese blood donors (Li et al. OBI symposium, Guangzhou 2014) An1- HBs An1- HBc DNA 27

28 OBI and liver disease: summary 70 N= % of OBI HCC HCC +HCV CLD CLD+HCV Control Clinical circumstances

29 Infec1vity of OBI Author Country Number N, (%) infected Genotype Reference OBI recipients Satake Japan 95 1/33 (3) C (A) Transfusion 2007;47:1197 Yuen Hong Kong 10 (67 units) 1/49 (2) B/C Clin Inf Dis 2011; 52: 624 Su Taiwan 11 (75) 3/13 (23) B Transf Med 2011; 21: 33 Allain Europe 24 (105) 46/105-15% (29) A/D Transfusion 2012; 53:1405 Seed Australia 17 (29) 35/427 (8.2) A/C Vox Sang 2015; 108:113 Overall es1mate 10-15%, Lelie

30 Factors influencing infec1vity of HBV by transfusion (Allain et al. Transfusion, 2013) Viral dose (viral load x volume of plasma transfused) FFP = 200ml FFP vs RCC P< PC = 50ml RCC = 20ml Infec1ous dose 1050 cps ( ) Presence of an1- HBs In donor blood (an1- HBc+/an1- HBs+) P= In vaccinated recipient From other transfusion received Immune status of recipient Not significant Naturally deficient (old age, HIV infec1on, congenital ID) Chemotherapy for Cancer, leukaemia etc Immunosuppression for bone marrow or organ transplanta1on 30

31 Conclusions HBV infec1on remains a major blood safety issue Epidemiology varies according to genotype No single screening test can provide op1mal blood safety An1- HBc in endemic areas affects the blood supply HBsAg + NAT with clinical sensi1vity <4 IU/ml needed HBV DNA reac1ve requires confirma1on Muta1ons may affect HBsAg detec1on Vaccinated donors may be infected Occult HBV (OBI) is important and 10-15% infec1ous