title: Prevention of MHC-alloimmunization by UV-B irradiation in a murine model: effects of UV dose and number of transfused cells.
abstract: The optimal dose of UV-B radiation for prevention of in vivo alloimmunization (AI) against major histocompatibility complex (MHC) antigens was investigated in a murine transfusion model. Two groups with five C57BL/6 mice (H-2b) each were transfused at weekly intervals with 1 x 10(5) or 1 x 10(6) DBA/2 (H-2d) leucocytes. Both suspensions induced anti-H-2d antibodies in all mice after the second transfusion. The minimal UV-B dose required for abolition of alloreactivity in the mixed leucocyte reaction (MLR) was 0.6 J/cm2. This dose completely prevented the onset of MHC-AI in all five mice transfused with six suspensions containing 1 x 10(5) leucocytes. In contrast, suspensions with 1 x 10(6) leucocytes and exposed to 0.6 J/cm2 induced immunization in 4/5 mice. Further increase of the dose to 1.8 or 5.4 J/cm2 did not prevent the onset of MHC-AI. The use of UV radiation for prevention of secondary MHC-AI was investigated in five mice with a primed immune system. Transfusion of suspensions with 1 x 10(5) leucocytes and irradiated at a dose of 1.8 J/cm2 did not prevent booster reactions. We conclude that the number of leucocytes per transfusion determines the efficacy of UV irradiation for the prevention of MHC-AI. For UV irradiation of human platelet concentrates (PCs) we propose to reduce the number of leucocytes by centrifugation prior to UV exposure. UV-B irradiation of PCs with high numbers of leucocytes may not be effective for prevention of alloimmunization.
authors.affiliation: Department of Immunohaematology, University Hospital Utrecht, The Netherlands.
authors.forename: M A
authors.initials: MA
authors.lastname: Grijzenhout
authors.forename: M I
authors.initials: MI
authors.lastname: Aarts-Riemens
authors.forename: F H
authors.initials: FH
authors.lastname: Claas
authors.forename: H C
authors.initials: HC
authors.lastname: van Prooijen
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000276:immunology / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D007518:Isoantibodies / Q000276:immunology*; D017708:Leukocyte Transfusion / Q000009:adverse effects*; D007962:Leukocytes / Q000276:immunology / Q000528:radiation effects; D008285:Major Histocompatibility Complex / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D017713:Platelet Transfusion; D014466:Ultraviolet Rays
chemical_list: D007518:Isoantibodies