Use of 8-methoxypsoralen and ultraviolet-A pretreated platelet concentrates
to prevent alloimmunization against class I major histocompatibility
antigens
NH Grana and KJ Kao
Department of Pathology, University of Florida College of Medicine,
Gainesville 32610-0275.
The use of 8-methoxypsoralen (8-MOP) and UV-A irradiation to inactivate
contaminating donor leukocytes in platelet concentrates and to prevent
primary alloimmunization against donor class I major histocompatibility
(MHC) antigens in mice was investigated. CBA/CaH-T6J mice with the H2k
haplotype and BALB/cByJ mice with the H2d haplotype were used as donors and
recipients, respectively. The mixed leukocyte reaction between these two
strains of mice showed that treatment of spleen cells with 500 ng/mL 8-MOP
and 5J/cm2 UV-A inhibited 99% of responder and 92% of stimulator function.
There was no measurable loss of platelet aggregating activity after the
treatment. After two weekly transfusions of platelets without any
treatment, 93% of control mice (n = 15) developed anti-H2k antibody. In
contrast, only 33% of mice (n = 15) receiving platelets treated with 8-MOP
and UV-A became alloimmunized. After six weekly platelet transfusions, all
mice became alloimmunized. Nevertheless, the mean titers of anti-H2k
antibody in sera of the treated groups were significantly lower than the
control groups. One hour posttransfusion recoveries of 51Cr-labeled donor
platelets were also higher in mice transfused with the treated platelets.
Thus, the pretreatment of platelet concentrates with 8-MOP and UV-A
irradiation effectively reduced the alloantigenicity of class I MHC
molecules. The implication of this finding in relation to the mechanism by
which donor leukocytes allosensitize recipients is discussed.
Volume 77,
Issue 11,
pp. 2530-2537,
06/01/1991
Copyright © 1991 by The American Society of Hematology
