Bang A, Speck E R, Blanchette V S, Freedman J, Semple J W
Division of Hematology, St Michael's Hospital, Toronto, Ontario, Canada.
Blood. 1996 Oct 15;88(8):2959-66.
Leukoreduced allogeneic platelet transfusions have been previously shown to initially stimulate an in vitro cellular cytotoxicity and subsequently Induce the formation of immunoglobulin G (IgG) antidonor alloantibodies. To further characterize these responses and determine if they are related, recipient BALB/c H-2d mice were treated with aminoguanidine (AMG), a selective inhibitor of inducible nitric oxide synthase (iNOS), and transfused weekly with 2 x 10(8) C57BL/6 H2b platelets. In control, non-AMG-treated mice, transfusion significantly (P < .01) increased serum levels of interferon-gamma (IFN-gamma) by day 1 posttransfusion (PT). IFN-gamma returned to pretransfusion levels by day 3 PT, and its production was not affected by AMG treatment. Serum interleukin-4 (IL-4), on the other hand, was undetectable before and during the transfusion protocol. By day 3 PT, recipient spleen cells could mediate in vitro anti-P815 (auto), anti-EL4 (allo), and anti-R1.1 (third-party MHC) cytotoxicity, and these responses were maximal by day 7 PT. Concurrently, a significant reduction in the vitro ability of recipient splenocytes to respond to Concanavalin A (ConA) was observed; this was not seen with lipopolysaccharide (LPS) stimulation. Elevated levels of NO2- were found in the ConA culture supernatants from transfused mice at day 3 PT. Serum antidonor alloantibodies were detected by the fifth platelet transfusion. AMG treatment of recipient mice significantly inhibited the transfusion. Induced cytotoxicity and ConA-stimulated NO2- production, and restored ConA-induced proliferation to normal levels. AMG appeared to selectively inhibit platelet-induced alloantibody production in that it did not affect antibody production induced by transfusions with 10(5) allogeneic leukocytes or by immunization with a foreign protein antigen, human gamma globulin, in adjuvant therapy. These results indicate that an in vivo AMG-sensitive mechanism is essential for recipients to initiate a humoral IgG immune response against allogeneic platelets.
白细胞滤除的异体血小板输血先前已显示，最初会刺激体外细胞毒性，随后诱导免疫球蛋白G（IgG）抗供体同种抗体的形成。为了进一步表征这些反应并确定它们是否相关，对受体BALB/c H-2d小鼠用氨基胍（AMG）进行处理，氨基胍是诱导型一氧化氮合酶（iNOS）的选择性抑制剂，每周给其输注2×10⁸个C57BL/6 H2b血小板。在对照的未用AMG处理的小鼠中，输血后第1天（PT）血清干扰素-γ（IFN-γ）水平显著（P <.01）升高。IFN-γ在输血后第3天恢复到输血前水平，其产生不受AMG处理的影响。另一方面，在输血方案实施前和实施期间未检测到血清白细胞介素-4（IL-4）。到输血后第3天，受体脾细胞可介导体外抗P815（自身）、抗EL4（同种异体）和抗R1.1（第三方主要组织相容性复合体）细胞毒性，并且这些反应在输血后第7天达到最大。同时，观察到受体脾细胞对刀豆球蛋白A（ConA）反应的体外能力显著降低；脂多糖（LPS）刺激未出现这种情况。在输血后第3天，在输注小鼠的ConA培养上清液中发现NO₂⁻水平升高。到第五次血小板输血时检测到血清抗供体同种抗体。对受体小鼠进行AMG处理显著抑制了输血诱导的细胞毒性和ConA刺激的NO₂⁻产生，并使ConA诱导的增殖恢复到正常水平。AMG似乎选择性地抑制血小板诱导的同种抗体产生，因为它不影响用10⁵个异体白细胞输血或用佐剂疗法中的外来蛋白质抗原人γ球蛋白免疫诱导的抗体产生。这些结果表明，体内AMG敏感机制对于受体启动针对异体血小板的体液IgG免疫反应至关重要。
