Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway.
Department of Hematology, Oslo University Hospital, Oslo, Norway.
Transfusion. 2021 Apr;61(4):1222-1234. doi: 10.1111/trf.16282. Epub 2021 Feb 13.
Patients can form antibodies to foreign human leukocyte antigen (HLA) Class I antigens after exposure to allogeneic cells. These anti-HLA class I antibodies can bind transfused platelets (PLTs) and mediate their destruction, thus leading to PLT refractoriness. Patients with PLT refractoriness need HLA-matched PLTs, which require expensive HLA typing of donors, antibody analyses of patient sera and/or crossmatching. An alternative approach is to reduce PLT HLA Class I expression using a brief incubation in citric acid on ice at low pH.
Apheresis PLT concentrates were depleted of HLA Class I complexes by 5 minutes incubation in ice-cold citric acid, at pH 3.0. Surface expression of HLA Class I complexes, CD62P, CD63, phosphatidylserine, and complement factor C3c was analyzed by flow cytometry. PLT functionality was tested by thromboelastography (TEG).
Acid treatment reduced the expression of HLA Class I complexes by 71% and potential for C3c binding by 11.5-fold compared to untreated PLTs. Acid-treated PLTs were significantly more activated than untreated PLTs, but irrespective of this increase in steady-state activation, CD62P and CD63 were strongly upregulated on both acid-treated and untreated PLTs after stimulation with thrombin receptor agonist peptide. Acid treatment did not induce apoptosis over time. X-ray irradiation did not significantly influence the expression of HLA Class I complexes, CD62P, CD63, and TEG variables on acid treated PLTs.
The relatively simple acid stripping method can be used with irradiated apheresis PLTs and may prevent transfusion-associated HLA sensitization and overcome PLT refractoriness.
患者在接触同种异体细胞后会产生针对异源性人白细胞抗原（HLA）I 类抗原的抗体。这些抗 HLA I 类抗体可与输注的血小板（PLT）结合并介导其破坏，从而导致 PLT 反应性降低。PLT 反应性降低的患者需要 HLA 匹配的 PLT，这需要对供体进行昂贵的 HLA 分型、患者血清的抗体分析和/或交叉配型。替代方法是通过在冰上用柠檬酸短暂孵育来降低 PLT HLA I 类表达，使其处于低 pH 值。
通过在冰冷的柠檬酸中孵育 5 分钟，使富含血小板的分离物 PLT 耗尽 HLA I 类复合物，pH 值为 3.0。通过流式细胞术分析 HLA I 类复合物、CD62P、CD63、磷脂酰丝氨酸和补体因子 C3c 的表面表达。通过血栓弹性描记术（TEG）测试 PLT 功能。
与未处理的 PLT 相比，酸处理使 HLA I 类复合物的表达减少了 71%，潜在的 C3c 结合减少了 11.5 倍。酸处理后的 PLT 比未处理的 PLT 明显更活跃，但无论这种稳态激活增加多少，在用凝血酶受体激动肽刺激后，酸处理和未处理的 PLT 上的 CD62P 和 CD63 都被强烈上调。随着时间的推移，酸处理不会诱导细胞凋亡。X 射线照射不会显著影响 HLA I 类复合物、CD62P、CD63 和 TEG 变量在酸处理后的 PLT 上的表达。
相对简单的酸剥离方法可用于辐照后的富含血小板的分离物，可预防与输血相关的 HLA 致敏并克服 PLT 反应性降低。
