1. Human Parvovirus PARV4 in Blood and Plasma Products
Jacqueline Fryer
National Institute for Biological Standards and Control
SoGAT XX

2. Identification of PARV4 and detection in pooled plasma
Originally identified in a homeless drug abuser with acute viral infection syndrome; co-infected with HBV (Jones et al, J Virol. 2005)
PARV4 and related genotype (PARV5) detected in 4-5% of recent manufacturing plasma pools; higher prevalence in older pools
Both viruses found in approximately equal proportions
The highest viral loads in pools are ~ 106 copies/ml plasma
No correlation between B19V and PARV4/5 viral loads
PARV4 and PARV5 are highly conserved (92% nucleotide identity), but share limited homology with B19V and HBoV
(Fryer et al. EID 2006; Fryer et al. Transfusion 2007)

3. Phylogenetic analysis of parvovirus genomes
Primate, chipmunk, bovine parvoviruses
Adeno-associated and avian parvoviruses
Human bocavirus, canine and bovine parvoviruses
Parvoviruses from carnivores, rodents and pig
Porcine parvovirus 2
Genus Erythrovirus
Genus Dependovirus
Genus Bocavirus
Genus Amdovirus
Genus Parvovirus

4. Are PARV4 & PARV5 present in products derived from these plasma pools?
Clotting factor VIII concentrates
175 lots, 12 products, 10 manufacturers
Expiry dates (plasma sourced ~5 yrs prior to expiry date)
Reconstituted in sterile H20, 1ml extracted on MagNA Pure LC Extractor
PARV4/5 detection by conventional PCR (ORF2 primers)
Viral loads determined by consensus real-time PCR

5. PARV4 and PARV5 in factor VIII concentrates
Product
/ Manufacturer
Expiry date
No. of lots tested
Purification process
Virus inactivation
No. of positive lots by PCR
PARV4/PARV5
B19V
1/A 37
Precipitation
None 3 23
2/B 2 1
3/C 5
4/D
5/E 55 14 9
6/C
1985
Dry heat (68 °C, 72 h)
4/F
Precipitation and adsorption
Wet heat (heptane) (60 °C, 20 h)
7/E 8
8/A
1986 4
Precipitation (plus further purification)
Steam treatment (60 °C, 10 h)
9/EGH 16
Monoclonal antibody
Pasteurisation (60 °C, 10 h)
10/I 13
Solvent/detergent 7
11/I
Dry heat (80 °C, 72 h)
12/J 18
Affinity chromatography
Solvent/detergent, dry heat (80 °C, 72 h)
No. positive/total tested
28/175
70/175
Percent positive
16%
40%

6. Prevalence of PARV4, PARV5 and B19V in factor VIIIs manufactured over the past 30-35 years
PARV4 and PARV5
B19V
PARV4/PARV5 and B19V
Negative for these viruses

7. Analysis of PARV4/5-positive factor VIII concentrates
Prevalence of PARV4/5 vs. age of product
Pre-1990 expiry:
23% PARV4/5 (45% B19V)
Post-1990 expiry:
2% PARV4/5 (30% B19V)
Viral loads
PARV4/5; up to 3 x105 copies/ml product
B19V; up to 2.5 x108 copies/ml product
Sequence analysis
7/28 PARV4
19/28 PARV5
2/28 both PARV4 and PARV5

8. Summary
PARV4 and PARV5 present in coagulation factor VIII products manufactured over past years
Prevalence of PARV4 and PARV5 higher in ‘older’ products (expiring pre-1990) compared to recent products (expiring post- 1990) (23% vs. 2%)
Increased blood safety in early 1980s (HIV epidemic); Screening / exclusion of ‘high risk’ donors
PARV4 sequences from year period highly conserved (>99% nucleotide identity), same for PARV5
Prevalence of PARV5 higher in ‘older’ factor VIII products, analogous to parvovirus B19 genotypes 1 & 2
Implications for recipients of plasma and plasma products in terms of PARV4/5 contamination are unknown
Nothing yet known of role of PARV4/5 in human disease

9. Acknowledgements NIBSC Sally Baylis Tony Hubbard Nita Shah
Morag Ferguson
Janice Blinder
Philip Minor
Blood Systems Research Institute, California/
University of California
Eric Delwart