Recipients potentially infected with parvovirus B19 by red blood cell products

BACKGROUND: Since 2000, blood donor screening for parvovirus B19 (B19) by nucleic acid testing (NAT) at the Ulm Institute has been conducted 6 to 8 weeks postdonation, that is, after transfusion of cellular blood products, whereas at the Frankfurt Institute all donations are screened before releasing any blood product. In this study, we evaluated the infectivity of B19-positive blood products in relation to the virus concentration in the transfused blood component. STUDY DESIGN AND METHODS: Recipients were classified into two groups (A, transfused with blood products with B19 virus load less than 105 IU/mL; and B, transfused with blood products with B19 virus load greater than 105 IU/mL). Phylogenetic analyses were done for B19 DNA-positive donor and recipient pairs in the variant VP-1u genome region. All samples were investigated for immunoglobulin (Ig)M and IgG B19 antibodies. RESULTS: B19 DNA was detected in 9 of 18 recipients of red blood cells (RBCs) from Group B, whereas none of the 16 recipients of RBCs from Group A were positive for B19 DNA (p = 0.016). Phylogenetic analysis demonstrated identical genomic sequences between the donors and recipients. Because recipient B19 DNA and antibody results were not available before transfusion, we interpret our overall data to indicate equivocal evidence of B19 transmission by RBC transfusion. CONCLUSION: B19 transmission by cellular blood products correlates with the virus concentration and the concentration of neutralizing antibodies. Thus, blood donor screening for B19 by minipool NAT should be done to supply at-risk patients (e.g., immunosuppressed patients) with B19-negative blood components.