West Nile virus in plasma is highly sensitive to methylene blue-light treatment.
Level 5 - mechanism / opinion, no new human data
In vitro laboratory experiment evaluating viral inactivation in spiked plasma units
PubMed 15157256 · doi:10.1111/j.1537-2995.2004.03424.x
What was done
Fresh frozen plasma (FFP) units (300 ml each) were spiked with West Nile virus (WNV). Methylene blue (MB, 0.8-1 µmol/l) was added, and units were illuminated with white light (30,000-45,000 Lux) or monochromatic yellow light (20-40 J/cm²). Viral infectivity was measured by bioassay, and viral RNA was quantified using real-time PCR under standard and suboptimal conditions, as well as in rechallenge experiments with repeated WNV spiking (approx. 10⁵ CFU/ml) and repeated illumination without replenishing MB.
What was found
Complete inactivation of WNV was achieved within 2 minutes using white light (30,000-45,000 Lux) with MB. Yellow light exposure for 2.5 to 5 minutes (20-40 J/cm²) reduced viral infectivity by 5.75 log10-steps. Rechallenge experiments demonstrated residual inactivation capacity, and real-time PCR confirmed rapid destruction of viral RNA.
Why it matters
This study demonstrates that standard methylene blue photochemical treatment protocols can eliminate high loads of West Nile virus from fresh frozen plasma, supporting its utility for blood safety.
Limits
The abstract does not state the total number of plasma units tested or specific replicate counts. Findings represent an in vitro spiked plasma model and do not measure potential effects of treatment on plasma coagulation factor retention or clinical outcomes in recipients.
Cited by
- supports Methylene blue is used in the treatment of blood plasma supply to eliminate infectious pathogens.