Stability of antigens on leukocytes in banked platelet concentrates:
decline in HLA-DR antigen expression and mixed lymphocyte culture
stimulating capacity following storage
ME Sherman and WH Dzik
New England Deaconess Hospital, Harvard Medical School, Boston, MA 02215.
Repeatedly transfused thrombocytopenic patients frequently form antibodies
directed against human leukocyte antigens (HLA) and become unresponsive to
random donor platelet transfusions. Although exposure to foreign antigens
borne on donor leukocytes appears necessary to provoke primary
sensitization, the stability of leukocyte antigens during routine platelet
storage is largely unknown. Accordingly, we serially measured the
expression of surface markers on leukocytes derived from platelet
concentrates during storage using immunofluorescence and flow cytometry.
Our results indicate that the expression of class I HLA antigens, Leu-4 (T
cell), and HLe-1 (pan leukocyte) remained stable on lymphocytes under
standard platelet storage conditions, but that the percentage of
lymphocytes bearing class II HLA antigens declined significantly over time.
This decline in lymphocyte HLA class II expression was associated with a
significantly diminished ability of stored leukocytes to stimulate
blastogenesis in mixed lymphocyte culture. However, leukocytes retained the
ability to respond in mixed lymphocyte culture (MLC) following storage. We
also performed studies on lymphocytes cultured in the presence of
cyclohexamide, which suggested that the expression of class I HLA antigens
and B2 microglobulin are highly sensitive to the inhibition of protein
synthesis, whereas the expression of class II HLA antigens, Leu- 4, and
HLe-1 are not. Our results may prove useful in understanding the mechanisms
that lead to platelet refractoriness and in designing strategies to prevent
HLA alloimmunization.
Volume 72,
Issue 3,
pp. 867-872,
09/01/1988
Copyright © 1988 by The American Society of Hematology
