Departamento de Hemoterapia e Terapia Celular, Hospital Israelita Albert Einstein, São Paulo, Brazil.
Universidade Estadual de Campinas, São Paulo, Brazil.
Transfus Med. 2020 Aug;30(4):317-323. doi: 10.1111/tme.12687. Epub 2020 Jun 2.
One of the strategies used to reduce the risk of haemolysis due to ABO-minor incompatible platelet transfusions is to perform a screening test to identify group O donors with high titres of anti-A and anti-B. However, critical immunoglobulin M/ immunoglobulin G (IgM/IgG) titres remain unclear.
This study aimed to determine IgM titres of anti-A and anti-B in individual donor serum vs platelet products plasma and identify a possible association between IgM/IgG titres, haemolysin test and IgG subclasses in Brazilian blood donors from group O.
IgM anti-A and Anti-B titration tests were performed on single-donor serum and platelet product plasma by gel agglutination (GA) at room temperature. For IgG anti-A and anti-B titration, serum was first treated with 0.01 M dithiothreitol (DTT), and the test was performed by GA with incubation at 37°C. Dilution of 1:64 as the cut-off was considered for both IgM/IgG. The qualitative haemolysin test was performed in tube, adding AB fresh serum, with incubation at 37°C. IgG subclasses were determined by GA using specific monoclonal antibodies.
An association between anti-A and anti-B IgM titres and haemolysin were demonstrated (P < .001). IgM titres in plasma samples from platelet components correlated to those in single-serum samples. IgG1/IgG3 subclasses were associated with total haemolysis and titres above 64, whereas IgG2/IgG4 subclasses were associated with the absence of haemolysis and titres below 64 (P < .001).
Our data suggest that a value of 64 as a critical titre can be used as a screening test of anti-A and anti-B IgM to prevent transfusion reactions. This can be a safe and cost-effective approach for managing ABO-incompatible platelet transfusions.
减少因 ABO 次要血型不合血小板输注导致溶血风险的策略之一是进行筛选试验，以识别具有高抗-A 和抗-B 效价的 O 型供体。然而，临界免疫球蛋白 M/免疫球蛋白 G（IgM/IgG）效价尚不清楚。
本研究旨在确定个体供体血清与血小板制品血浆中抗-A 和抗-B 的 IgM 效价，并确定巴西 O 型血供体的 IgM/IgG 效价、溶血试验和 IgG 亚类之间可能存在的关联。
通过室温凝胶凝集（GA）对单个供体血清和血小板制品血浆中的 IgM 抗-A 和抗-B 进行滴定试验。对于 IgG 抗-A 和抗-B 滴定，血清先用 0.01 M 二硫苏糖醇（DTT）处理，然后在 37°C 孵育下进行 GA 试验。将 1:64 的稀释度视为 IgM/IgG 的截断值。在试管中进行定性溶血试验，加入 AB 新鲜血清，在 37°C 孵育。使用特异性单克隆抗体通过 GA 确定 IgG 亚类。
抗-A 和抗-B IgM 效价与溶血之间存在关联（P<0.001）。血小板成分血浆样本中的 IgM 效价与单一血清样本中的效价相关。IgG1/IgG3 亚类与总溶血和效价高于 64 有关，而 IgG2/IgG4 亚类与无溶血和效价低于 64 有关（P<0.001）。
我们的数据表明，64 作为临界效价可用于筛选抗-A 和抗-B IgM，以预防输血反应。这是一种安全且具有成本效益的管理 ABO 不合血小板输注的方法。
