Treatment of T. cruzi infected human platelet concentrates with aminomethyltrimethyl psoralen (AMT) and ultraviolet A (UV-A) light: preliminary results

RESUMO

The present measures adopted to prevent transfusion-associated Chagas' disease include screening of blood donors, and/or the inactivation of T. cruzi in collected blood using gentian violet (GV), as a trypanocidal agent. In this study, we investigated the efficacy of the combined use of AMT and UV-A in inactivating T. cruzi in infected human platelet concentrates. Human platelet concentrates were infected with T. cruzi (2 x 10(8)/ml) of the Y strain, transfered to PL 269 (Fenwal Laboratories) containers, and treated with GV (250 micrograms/ml), and ascorbic acid (1 mg/ml); GV, ascorbic acid and UV-A; GV and UV-A; AMT (40 microG/ml) and ascorbic acid; AMT, ascorbic acid and UV-A; AMT and UV-A; UV-A alone; and untreated (control). All UV-A treated platelet concentrates were exposed to UV-A doses of 24, 92, 184, 276, 368 and 644 kJ/m2, and the microscopical research of active T. cruzi was performed, using the microhematocrit technique, 1, 6 and 24 hours after each treatment. A high number of active forms of T. cruzi was observed in all condictions, except when GV was used as the trypanocidal agent, providing evidence of the failure of AMT and UV-A in inactivating T. cruzi in infected human platelet concentrates.