Dipyridamole can improve the specificity of photodynamic sterilization of RBC concentrates, thereby increasing the practical applicability of this photodecontamination method.

Porphyrin Tri-P(4) may be a suitable photosensitizer for sterilization of RBCs. However, further exploration to optimize the method is necessary to reach clinically acceptable goals.

PDT of RCC with Tri-P(4) for 60 min inactivates a wide range of pathogens, but not cell-associated HIV and a non-enveloped virus, and compromises RBC quality. This reduces the suitability of PDT with Tri-P(4) for red cell sterilization. Therefore, further improvements in the treatment procedures to potentiate pathogen inactivation and to preserve RBC integrity will be required to generate an effective treatment for sterilizing RCC.

Pathogen inactivation of CBSC with Tri-P(4)-mediated PDT is feasible at contamination level up to 10 to 20 colony-forming units per mL and can be considered when ex vivo expansion culture is anticipated. However, this treatment is not recommended for transplantation purposes at this time. Further investigations may elucidate why engraftment is diminished.