INACTIVATION BY PHTHALOCYANINE PHOTOSENSITIZATION OF MULTIPLE FORMS OF HUMAN-IMMUNODEFICIENCY-VIRUS IN RED-CELL CONCENTRATES

Background: The use of phthalocyanines in conjunction with red light h as been shown to inactivate model lipid-enveloped viruses in red cell concentrates. The ability of this treatment to inactivate multiple for ms of human immunodeficiency virus (HIV) was evaluated in this study. Study Design and Methods: The phthalocyanines used were aluminum phtha locyanine tetrasulfonate (AlPcS(4)) and the silicon phthalocyanines HO SiPcOSi(CH3)(2)-(CH2)(3) N(CH3)(2) (Pc 4), and HOSiPcOSi(CH3)(2)(CH2)( 3) N+(CH3I-(Pc 5). HIV was studied in a cell-free form, in an actively replicating form, in latently infected cells, and in blood from HIV-p ositive patients. Results: All three phthalocyanines inactivate greate r than or equal to 10(5) infectious doses of cell-free HIV. However, o nly Pc 4 effectively inactivated actively replicating HIV and latently infected cells. The latter was about four times as sensitive to inact ivation as was actively replicating HIV. Increasing the hematocrit of red cells during treatment decreased the rate of inactivation, especia lly at lower light doses. Under treatment conditions that completely i nactivated the laboratory isolates of HIV, cell-associated HIV in bloo d from HIV-positive patients was also completely inactivated. The poly merase chain reaction signal from the gag gene of HIV was not affected on treatment of cell-free virus, but it was reduced after treatment o f cell-associated HIV, particularly in some latently infected cell lin es. Conclusion: Pc 4 and red light are effective in eliminating the in fectivity of HIV in red cell concentrates. The usefulness of this appr oach for blood banking depends on future demonstration of the preserva tion of red cell circulatory survival and function in vivo.