Human parvovirus PARV4 in clotting factor VIII concentrates.
OBJECTIVE
Parvoviruses are small non-enveloped DNA viruses, relatively resistant to virus inactivation procedures. The recently identified human parvovirus PARV4, including a related genotype 2 virus (also termed PARV5), has been found to be a contaminant of pooled plasma used in the manufacture of plasma-derived products. This report describes an investigation to determine whether PARV4 is present in clotting factor concentrates.


METHODS
Factor VIII concentrates manufactured in the past 30-35 years were screened for PARV4 and human parvovirus B19 (B19V) sequences. Viral loads in products testing positive for PARV4 were quantified using a consensus TaqMan assay designed to a highly conserved region. DNA sequence analysis was performed to confirm the genotypes present.


RESULTS
From a total of 175 lots of factor VIII concentrate, 28 of these contained PARV4 sequences, and in two lots both genotypes 1 and 2 were found to be present. The highest viral loads observed exceeded 10(5) copies per ml. The majority of factor VIII concentrates testing positive for PARV4 were manufactured in the 1970s and 1980s. Human B19V was also a frequent contaminant of these products.


CONCLUSIONS
PARV4 was detected in 16% of factor VIII concentrates, particularly in older batches from the 1970s and 1980s. The significance in terms of the viral safety and potential transmission to recipients of these products is not yet known.
Fryer
J F
JF
Division of Virology, National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Hertfordshire EN6 3QG, UK.
Hubbard
A R
AR
Baylis
S A
SA
D001688:Biological Products / Q000032:analysis* / Q000097:blood; D004279:DNA, Viral / Q000302:isolation & purification; D004340:Drug Contamination; D005169:Factor VIII / Q000032:analysis* / Q000627:therapeutic use; D006801:Humans; D010322:Parvoviridae Infections / Q000097:blood*; D017992:Parvovirus / Q000302:isolation & purification*; D010949:Plasma / Q000821:virology; D019562:Viral Load
D001688:Biological Products; D004279:DNA, Viral; D005169:Factor VIII