Standardisation of P. falciparum HBV, HCV and NAT Sally Baylis, NIBSC SoGAT XVIII

Malaria 300 to 500 million cases annually (1.5 to 2.7 million deaths) 300 to 500 million cases annually (1.5 to 2.7 million deaths) 4 plasmodia species cause malaria in man 4 plasmodia species cause malaria in man Plasmodium falciparum causes ~80% of cases (malaria tropica) Plasmodium falciparum causes ~80% of cases (malaria tropica) P. vivax (~15% cases), P. ovale, P. malariae less severe P. vivax (~15% cases), P. ovale, P. malariae less severe Transmitted by night-biting Anopheles mosquitoes Transmitted by night-biting Anopheles mosquitoes Complex lifecycle with species variation Complex lifecycle with species variation Asexual in man Asexual in man Sexual in mosquito Sexual in mosquito

R. Menard, Nature, 433, 113-4

Malaria cont. In non-immune host e.g. visitors to endemic areas In non-immune host e.g. visitors to endemic areas Incubation period normally 1-3 weeks Incubation period normally 1-3 weeks Seroconversion up to 4 months after infection Seroconversion up to 4 months after infection Symptoms - fever, chills, malaise, headaches etc. Symptoms - fever, chills, malaise, headaches etc. In the semi-immune host e.g. immigrants & visitors from endemic areas, those taking prophylaxis In the semi-immune host e.g. immigrants & visitors from endemic areas, those taking prophylaxis Delayed onset of illness & mild symptoms Delayed onset of illness & mild symptoms In the “immune” host In the “immune” host Malaria is less severe & asymptomatic in 80% of individuals Malaria is less severe & asymptomatic in 80% of individuals

Malaria and Transfusion Transfusion-transmitted malaria is rare, but potentially serious consequence of blood transfusion Transfusion-transmitted malaria is rare, but potentially serious consequence of blood transfusion US, ~ 90 cases since 1963 US, ~ 90 cases since 1963 Canada, 3 cases ( ) Canada, 3 cases ( ) UK, 5 cases in last 15 years UK, 5 cases in last 15 years Generally prevention of transfusion transmitted malaria by donor selection to identify those “at risk” e.g. Generally prevention of transfusion transmitted malaria by donor selection to identify those “at risk” e.g. Born/ lived in endemic areas Born/ lived in endemic areas Visitors to endemic areas Visitors to endemic areas Had malaria Had malaria

Malaria and Transfusion cont. Most recent UK case of transfusion transmitted malaria in 2003 (Kitchen et al., Vox Sang. 88, 200-1) Most recent UK case of transfusion transmitted malaria in 2003 (Kitchen et al., Vox Sang. 88, 200-1) Recipient: Recipient: Male (age 50) with sickle cell disease & renal failure became symptomatic ~ 2 months after transfusion Male (age 50) with sickle cell disease & renal failure became symptomatic ~ 2 months after transfusion Blood films – P. falciparum trophozoites; 5.2% parasitaemia Blood films – P. falciparum trophozoites; 5.2% parasitaemia No history of travel outside UK since 1957 No history of travel outside UK since 1957 Donor: Donor: Female (age 38) from Ghana, migrated to UK & not returned to Ghana in previous 8 years Female (age 38) from Ghana, migrated to UK & not returned to Ghana in previous 8 years No history of malaria No history of malaria Malaria Ab EIA positive serum archive sample (Newmarket) Malaria Ab EIA positive serum archive sample (Newmarket) Follow up blood samples from donor, malarial ab +ve & P.falciparum DNA was detected by qPCR (~5 parasites/μl - 8 months post-donation; Follow up blood samples from donor, malarial ab +ve & P.falciparum DNA was detected by qPCR (~5 parasites/μl - 8 months post-donation; parasites/μl - 12 months post-donation) parasites/μl - 12 months post-donation)

Screening for Malaria Deferral & antibody screen for donor reinstatement e.g. the UK – Newmarket EIA; US no approved tests Deferral & antibody screen for donor reinstatement e.g. the UK – Newmarket EIA; US no approved tests However will not detect “window” However will not detect “window” Stained blood films – routine method for diagnosis (since 1900) Stained blood films – routine method for diagnosis (since 1900) Slow, requiring highly trained microscopists Slow, requiring highly trained microscopists Antigen detection Antigen detection Lacking in sensitivity Lacking in sensitivity Nucleic Acid Detection Nucleic Acid Detection Potentially may not detect very low levels of parasitaemia Potentially may not detect very low levels of parasitaemia

NIBSC Proposal for Production of Standards for P. falciparum For standardisation of NAT assays (qualitative and quantitative) For standardisation of NAT assays (qualitative and quantitative) Screening of blood for transfusion and tissues: exclusion of infected donations (run controls); determination of levels of parasitaemia where TTIs occur; validation of assay sensitivities Screening of blood for transfusion and tissues: exclusion of infected donations (run controls); determination of levels of parasitaemia where TTIs occur; validation of assay sensitivities Diagnosis and clinical management of malaria: standardisation of commercial and in-house tests – harmonisation of results to a single reference material Diagnosis and clinical management of malaria: standardisation of commercial and in-house tests – harmonisation of results to a single reference material Vaccine studies: cross-comparison of studies, parasite loads, efficacy etc. Vaccine studies: cross-comparison of studies, parasite loads, efficacy etc.

Candidate P. falciparum Standards Freeze-dried blood from patient (~10% parasitaemia) Freeze-dried blood from patient (~10% parasitaemia) Liquid preparation of blood from patient (~7% parasitaemia) Liquid preparation of blood from patient (~7% parasitaemia) Liquid preparation of P. falciparum cultured in vitro to ~10% ring forms Liquid preparation of P. falciparum cultured in vitro to ~10% ring forms Liquid preparation of blood from patient (~0.007% parasitaemia) Liquid preparation of blood from patient (~0.007% parasitaemia)

R. Menard, Nature, 433, 113-4

Performance of Candidate P. falciparum Standards

Performance of Candidate Freeze-Dried P. falciparum Standard No significant loss of titre is observed following freeze-drying of patient blood (~10% parasitaemia) No significant loss of titre is observed following freeze-drying of patient blood (~10% parasitaemia) Accelerated degradation studies of this material are in progress Accelerated degradation studies of this material are in progress >8 months at -20 ºC, no change in titre >8 months at -20 ºC, no change in titre

Collaborative Study Commenced April 2005 Commenced April laboratories already received samples 9 laboratories already received samples 3 further laboratories are finalising receipt details 3 further laboratories are finalising receipt details Labs wishing to participate in the collaborative study should return form in meeting pack to S. Baylis Labs wishing to participate in the collaborative study should return form in meeting pack to S. Baylis

Replacement of the HBV DNA IS 97/746 The 1 st International Standard for HBV DNA was established by the WHO ECBS in October 1999 The 1 st International Standard for HBV DNA was established by the WHO ECBS in October 1999 Estimated date of exhaustion of the IS will be 2006 at current rate of usage Estimated date of exhaustion of the IS will be 2006 at current rate of usage Materials coded AA (97/746) & BB showed no significant difference in potency in the collaborative study Materials coded AA (97/746) & BB showed no significant difference in potency in the collaborative study ECBS noted that BB (made from the same stock as AA) could be reserved for potential future use as a replacement standard ECBS noted that BB (made from the same stock as AA) could be reserved for potential future use as a replacement standard

Replacement of the HBV DNA IS 97/746 cont. Additional stability studies required before BB able to replace AA Additional stability studies required before BB able to replace AA Propose small collaborative study, similar to that of the HCV RNA IS replacement Propose small collaborative study, similar to that of the HCV RNA IS replacement Aim to demonstrate the equivalence of the candidate replacement (BB) to AA Aim to demonstrate the equivalence of the candidate replacement (BB) to AA Real-time data on AA and BB samples Real-time data on AA and BB samples Accelerated degradation data on AA and BB Accelerated degradation data on AA and BB Aim to submit report to WHO ECBS by July 2006 Aim to submit report to WHO ECBS by July 2006

Replacement of the HCV RNA IS 96/798 Approximately 1250 vials remain of the 2 nd HCV IS 96/798 Approximately 1250 vials remain of the 2 nd HCV IS 96/798 Estimated date of exhaustion of the IS will be 2009 at current rate of usage Estimated date of exhaustion of the IS will be 2009 at current rate of usage Options for replacing the IS Options for replacing the IS 1 st & 2 nd IS derived from the same genotype 1a anti-HCV positive donation 1 st & 2 nd IS derived from the same genotype 1a anti-HCV positive donation Do we replace the IS with a donation positive for anti- HCV or negative for anti-HCV? Do we replace the IS with a donation positive for anti- HCV or negative for anti-HCV? 1 st & 2 nd IS diluted in cryosupernatant 1 st & 2 nd IS diluted in cryosupernatant Do we dilute a replacement IS in cryosupernatant or plasma? Do we dilute a replacement IS in cryosupernatant or plasma?

Acknowledgements David Padley, Alan Heath & Nita Shah, NIBSC David Padley, Alan Heath & Nita Shah, NIBSC Peter Chiodini, Hospital for Tropical Diseases, London Peter Chiodini, Hospital for Tropical Diseases, London Patricia Hewitt, NBS, London Patricia Hewitt, NBS, London Claire Swales, LSHTM, London Claire Swales, LSHTM, London