Viral metagenomics applied to blood donors and recipients at high risk for blood-borne infections

Abstract

Background: Characterisation of human-associated viral communities is essential for epidemiological surveillance and to be able to anticipate new potential threats for blood transfusion safety. In high-resource countries, the risk of blood-borne agent transmission of well-known viruses (HBV, HCV, HIV and HTLV) is currently considered to be under control. However, other unknown or unsuspected viruses may be transmitted to recipients by blood-derived products. To investigate this, the virome of plasma from individuals at high risk for parenterally and sexually transmitted infections was analysed by high throughput sequencing (HTS).

Materials and methods: Purified nucleic acids from two pools of 50 samples from recipients of multiple transfusions, and three pools containing seven plasma samples from either HBV-, HCV- or HIV-infected blood donors, were submitted to HTS.

Results: Sequences from resident anelloviruses and HPgV were evidenced in all pools. HBV and HCV sequences were detected in pools containing 3.8×10(3) IU/mL of HBV-DNA and 1.7×10(5) IU/mL of HCV-RNA, respectively, whereas no HIV sequence was found in a pool of 150 copies/mL of HIV-RNA. This suggests a lack of sensitivity in HTS performance in detecting low levels of virus. In addition, this study identified other issues, including laboratory contaminants and the uncertainty of taxonomic assignment of short sequence. No sequence suggestive of a new viral species was identified.

Discussion: This study did not identify any new blood-borne virus in high-risk individuals. However, rare and/or viruses present at very low titre could have escaped our protocol. Our results demonstrate the positive contribution of HTS in the detection of viral sequences in blood donations.

Figure 1

Amounts of known Anelloviruses in plasma samples of multi-transfused recipients and HBV−, HCV− and HIV-infected blood donors. Amounts were estimated by considering the number of reads included in contigs that match the reference sequence over 100 bp and the number of singletons with a hit match length covering at least 90 pb. Sequences sharing at least 80% nucleotide or amino acid identity with the best hit were classified as “known Anelloviruses”.