Hepatitis E virus is effectively inactivated by methylene blue plus light treatment

Abstract

Background and objectives: Photodynamic treatment with methylene blue (MB) and visible light is a well-established pathogen inactivation system for human plasma. This technique is routinely used in different countries. MB/light treatment was shown to inactivate several transfusion-transmittable viruses, but its efficiency for the inactivation of the quasi-enveloped hepatitis E virus (HEV) has not yet been investigated.

Materials and methods: Plasma units were spiked with cell culture-derived HEV and treated with the THERAFLEX MB-Plasma system using various light doses (30, 60, 90, and 120 J/cm² ). HEV titers in pre- and post-treatment samples were determined by virus titration and a large-volume plating assay to improve the detection limit of the virus assay.

Results: THERAFLEX MB-Plasma efficiently inactivated HEV in human plasma. Even the lowest light dose of 30 J/cm² inactivated HEV down to the limit of detection, with a mean log reduction factor of greater than 2.4 for the total process.

Conclusion: Our study demonstrates that the THERAFLEX MB-Plasma system effectively inactivates HEV in human plasma.

Keywords: hepatitis E virus; methylene blue; pathogen inactivation; plasma.