ABSTRACT
BACKGROUND: Human parvovirus B19 (B19) DNA can be frequently detected in plasma-derived coagulation factor concentrates. The production of some clotting factor products includes heat treatment steps for virus inactivation, but the effectiveness of such steps for B19 inactivation is unclear. Moreover, detailed transmission case reports including DNA sequence analysis and quantification of B19 DNA from contaminated heat-treated blood components have not been provided so far. Therefore, the correlation between B19 DNA in blood components and infectivity remains unclear. STUDY DESIGN AND METHODS: Asymptomatic B19 infections of two patients with hemophilia A were detected by anti-B19 seroconversion after administration of B19-contaminated heat-treated clotting factors. The suitability of nucleic acid sequence analysis for confirmation of B19 transmission was investigated. Furthermore, the B19 DNA level in blood components was determined and the drug administration was reviewed to calculate the amount of inoculated B19 DNA. RESULTS: Both B19 transmissions from clotting factor products could be confirmed by identical nucleic acid sequences of virus DNA from patients and blood components while sequences from unrelated controls could be differentiated. One patient received, for 4 days, a total of 180 mL vapor heat-treated prothrombin complex concentrate containing 8.6 x 10(6) genome equivalents per mL of B19 DNA. The other patient received 966 mL of low-contamination (4.0 x 10(3) genome equivalents/mL) dry heat-treated FVIII concentrate over a period of 52 days. CONCLUSION: B19 transmissions can be confirmed by nucleic acid sequencing. However, due to the low variability of the B19 genome, a large part of the B19 genome must be analyzed. The transmissions show that the applied heat treatment procedures were not sufficient to inactivate B19 completely.
Subject(s)
Factor VIII/therapeutic use , Parvoviridae Infections/transmission , Parvovirus B19, Human/isolation & purification , Virus Inactivation , Child, Preschool , DNA, Viral/genetics , Drug Contamination , Genome, Viral , Hemophilia A/therapy , Hot Temperature , Humans , Infant , Male , Parvoviridae Infections/blood , Parvoviridae Infections/virology , Parvovirus B19, Human/genetics , Sequence Analysis, DNA , Viral Load , ViremiaABSTRACT
A mixture of Tri-n-butyl phosphate (TNBP) and Polysorbate 80 (Tween 80) is often used for virus inactivation during the manufacture of medicinal products derived from human plasma. This procedure, known as solvent/detergent treatment, is of high effectiveness for inactivation of enveloped viruses. Tween 80 can be manufactured from bovine tallow or from vegetable material. As the bovine-derived Tween 80 is normally used for the solvent/detergent treatment, the question has been raised whether vegetable-derived Tween 80 can be applied as an alternative substance for the solvent/detergent treatment. Comparable inactivation studies were therefore performed using Vesicular Stomatitis Virus (VSV), Pseudorabiesvirus (PRV), Semliki Forest Virus (SFV) and Bovine Diarrhoea Virus (BVDV). In principle, no differences were observed in the effectiveness of the solvent/detergent treatment when bovine or vegetable-derived Tween 80 was used. The comparability in the efficiency of both detergents for virus inactivation was shown to be independent of solvent/detergent concentration, of temperature (16 degrees C and 6 degrees C vs. 27 degrees C and 25 degrees C) and protein concentration (10% and 5% human albumin). In summary, vegetable-derived Tween 80 is of the same effectiveness as bovine-derived Tween 80, when used for virus inactivation by the solvent/detergent treatment.
