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Persistent human erythrovirus infection in blood donors. D Candotti, N Etiz, A Parsyan, JP Allain. National Blood Service, UK Div. Transfusion Medicine, University of Cambridge, UK Public Health Laboratory, Ankara, Turkey. Issues and objectives. Background
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Persistent human erythrovirus infection in blood donors D Candotti, N Etiz, A Parsyan, JP Allain National Blood Service, UK Div. Transfusion Medicine, University of Cambridge, UK Public Health Laboratory, Ankara, Turkey
Issues and objectives Background • Chronic anaemia may occur in transfused immunosuppressed patients • Some preliminary evidence of persistent B19 infection (DNA+IgG) Study objectives - to determine the prevalence of persistent B19 infection in blood donors - to characterise persistent B19 genome - to assess the potential infectivity of persistent B19
NAT assays Human erythrovirus genotypes (HEV 1 (NIBSC 99/800) 2 (EDQM) 3 (D91.1 plasmid) Nested-PCR1 95% detection limit2 Q-PCR3 95% detection limit2 Dynamic range 25 50 50-5x1010 25 50 50 - 5x105 25 50 50 - 5x1010 1. Primers in the NS1 region 2. IU/ml or copies/ml 3. TaqMan-based assay using primers and probe in the NS1 region
Phylogenetic analysis of human erythrovirus 800 nt NS1/VP1u sequences Genotype 1 Genotype 2 100 100 100 UK South Africa 97 73 83 Malawi Ghana References Genotype 3 0.01
Serology of HEV DNA+ samples (Biotrin IgM & IgG kits) UKGhana Pos Neg Pos Neg IgM 1 8 1 12 IgG 9 0 10* 2 * S/COs of positives are significantly lower than with UK samples
100 90 80 70 60 % of the viral population 50 40 30 20 10 0 Sample id: IgG status: UK4523 positive UK4892 positive Gh2094 positive Gh2120 positive Gh1280 negative Gh2135 negative HEV DNA quantification in 6 plasmas chromatographed on protein G Eluted Flow through
IgG antibody to HEV genotype 1 and 3 Country N samples Reactive to antigen (%) tested Genotype 1 Genotype 3* UK 87 53 (60.9) ND Ghana 155 109 (70.3) 117 (75.5) *VP2 antigen from V9 strain was provided by Dr K Brown, NIH, USA
Conclusions • The prevalence of persistent human erythrovirus infection in random blood donors is approximately 1% • Viral load in persistent HEV infections is low (median 10E3) • 5-70% of persistent HEV appears uncomplexed (free) • HEV Genotype 3 is prevalent in Ghana • Serologic detection of antibody to genotype 3 with genotype 1 reagent is unsatisfactory
Acknowledgements Transfusion Medicine Unit, Komfo Anokye Teaching Hospital, Kumasi, Ghana Francis Sarkodie Shirley Owusu-Ofore National Institute for Biological Standards and Control, UK Dr. Sally Baylis Virology Lab., Armand trousseau Hospital, Paris, France Dr. Annabelle Servant Pr. Antoine Garbarg-Chenon Liverpool School of Tropical Medicine, UK Dr. Imelda Bates Dept. of Microbiology, Scientific Institut of Public Health, Brussels, Belgium Dr. Isabelle Thomas Natal Blood Transfusion Service, Pinetown, South Africa Dr. Theresa Nel Hematology branch, National Heart, Lung, and Blood Institut, Bethesda, USA Dr. Kevin Brown West Khartoum Umdurman Hospital Khartoum, Sudan Dr. A Youssef