Assessment of the hemostatic effectiveness of human platelets treated with
aminomethyltrimethyl psoralen and UV A light using a rabbit ear bleeding
time technique
SJ Wagner, L Bardossy, G Moroff, RY Dodd and MA Blajchman
Jerome H. Holland Laboratory for the Biomedical Sciences, American Red
Cross Blood Services, Rockville, MD 20855.
The photochemical aminomethyltrimethyl psoralen (AMT), in conjunction with
UV A light (UVA), has been shown to inactivate human immunodeficiency
virus-1 and model viruses in platelet suspensions under conditions that
have only a minimal effect on in vitro platelet properties. A rabbit ear
bleeding time technique was used to assess the hemostatic effectiveness of
human platelet suspensions treated with AMT/UVA. New Zealand White rabbits
were made thrombocytopenic by a combination of irradiation and heterologous
antirabbit platelet antiserum. Reticuloendothelial function in these
rabbits was suppressed by the intravenous administration of ethyl
palmitate. The hemostatic function of 1- and 5-day-old human platelet
suspensions (14.5% plasma) that had been treated on day 1 with 40
micrograms/mL AMT and 24 kJ/m2 UVA (1 x UVA) was evaluated by measuring
microvascular bleeding times after a standard incision. Comparable bleeding
times were observed after infusion with both control and AMT/UVA-treated
platelets stored for either 1 or 5 days. With the transfusion of AMT/1 x
UVA-treated platelets stored for 5 days, the mean (+/- SD) bleeding time
was 156.3 +/- 39.2 seconds (n = 10). With untreated platelets (no AMT/no
UVA), stored for 5 days, the mean bleeding time was 189.2 +/- 36.4 seconds
(n = 10). Neither AMT nor 1 x UVA treatment alone influenced the observed
bleeding times. In contrast, the hemostatic effectiveness of human platelet
suspensions was diminished if they were exposed to three times the standard
UVA dose (72 kJ/m2) on day 1 and stored for 4 more days, regardless of
whether AMT was present, with the mean bleeding time increasing to 442.2
+/- 122.6 seconds (n = 15, AMT present) or 396.0 +/- 45.9 seconds (n = 10,
AMT absent). These results are consistent with data obtained from in vitro
studies and indicate that virucidal AMT/1 x UVA treatment does not
influence platelet hemostatic function. However, the final conditions to
achieve these results must be carefully controlled.
Volume 82,
Issue 11,
pp. 3489-3492,
12/01/1993
Copyright © 1993 by The American Society of Hematology
