Parvovirus B19 DNA and antibodies in Chinese plasma donors, plasma pools and plasma derivatives
Authors: Sun Pan , Jiang Peng , Liu Qing , Zhang Rong , Wang Zongkui , Cao Haijun , Ye Xiangzhong , Ji Shangzhi , Han Jinle , Lu Kuilin , He Xuexin , Fan Jiajin , Cao Dawei , Zhang Yu , Yin Yongsheng , Chen Yunhua , Zhao Xuemei , Ye Shengliang , Su Na , Du Xi , Ma Li , Li Changqing 
Published: August 2023

Background
Human parvovirus B19 (B19V) is a common contaminant found in plasma pools and plasma derivatives. Previous studies were mainly focused on limited aspects, further assessment of prevalence of B19V DNA and antibodies in plasma donors, the contamination of B19V in pooled plasma and plasma derivatives should be performed in China.

Study Design and Methods
Individual plasma donors’ samples from four provinces and pooled plasma from four Chinese blood product manufacturers were collected and screened using B19V DNA diagnostic kits between October 2018 and May 2020. The positive samples were investigated for the seroprevalence of B19V antibodies and subjected to sequence analysis and alignment for phylogenetic studies. Moreover, 11 plasma donors who were B19V DNA-positive at their first testing were also followed during the later donation period. Additionally, 400 plasma pools and 20 batches of plasma derivatives produced by pooled plasma with a viral load of B19V DNA exceeding 104IU/mL were also collected and tested for B19V DNA and antibodies.

Objectives
To comprehensively and systematically determine the frequency and viral load of B19V DNA in plasma donors, pooled plasma, and plasma derivatives from four Chinese blood product manufacturers.

Results
A total of 17,187 plasma donors were analyzed and 44 (0.26%) specimens were found positive for B19V DNA. The quantitative DNA levels ranged from 1.01 × 101 to 5.09 × 1012 IU/mL. Forty-four DNA-positive specimens were also investigated for the seroprevalence of B19V antibodies, 75.0% and 2.3% of which were seropositive for B19V IgG and IgM antibodies, respectively. The phylogenic analyses showed that the prevalent genotypes in the four provinces’ plasma donors belonged to B19V Genotype 1. Eleven individual plasma donors who were B19V DNA-positive at the first donation were then followed for a period, and in general, the DNA levels of B19V gradually decreased. Moreover, 64.8% (259/400) of the pooled plasma was contaminated by B19V, with concentrations of 1.05 × 100–3.36 × 109IU/mL. Approximately 72.6% of the DNA-positive plasma pools were only moderately contaminated (<104 IU/mL), while 27.4% contained >104 IU/mL. Twenty batches of plasma derivatives produced by pooled plasma with a viral load of B19V DNA exceeding 104IU/mL were also tested. B19V was detected in 5/5 PCC samples and 5/5 factor VIII samples but was not found in the intravenous immune globulin and albumin samples.

Conclusion
The contamination of B19V in pooled plasma and plasma-derived clotting factor concentrates is serious. Whether B19V nucleic acid testing (NAT) screening of plasma and plasma derivatives is launched in China, blood product manufacturers should spontaneously perform B19V NAT screening in plasma donors and mini-pool plasma. These measures can ensure that samples with high titer B19V DNA are discarded in order to prevent and control this transfusion transmitted virus.