Background

The monocyte monolayer assay (MMA) is an in-vitro assay that can predict the outcome of blood transfusion of antigen positive units when serologically compatible blood is not available.

Materials and methods

Fifty-four patients testing positive by the antibody screening test using gel agglutination were further examined by the alloantibody identification panel to determine alloantibody specificity. After determining and categorizing the antibodies, patients' samples were examined using the MMA to determine the clinical significance of the detected alloantibodies. We also tested 2 seeding methods (24-well cell culture plates versus 8-well chamber-slides) and 3 visualization/staining techniques (unstained phase contrast, Leishman and Giemsa staining).

Results

35 out of the 54 cases (64.8%) had a monocyte index of >5% which is predictive of occurrence of hemolytic reaction after transfusion; 23 cases with antibodies known to be clinically significant [anti-C, anti-E, anti-c, anti-K, anti-Fy(a), anti Fy(b), anti-JK(b)], 2 with Anti-M specificity, 7 cases with autoantibodies and 3 cases with multiple antibodies. On the other hand, 19 out of the 54 (35.2%) cases included in the study showed a monocyte index of <5% which is predictive of absence of haemolytic reaction after transfusion. The 8-well chamber-slides were better than the 24-well culture plates, as the latter showed a lot of un-phagocytosed RBCs in the background. Also, Leishman staining was better than Giemsa staining with better and clearer differentiation between the RBCs, monocytes and phagocytic vacuoles.

Conclusion

MMA can be used as a surrogate cross-match test for the selection of blood units in cases where antigen-negative blood units are not available.

中文翻译：

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输血前检测中的单核细胞单层分析：为因同种免疫而反复出现交叉配型不良的患者输血的关键

背景

单核细胞单层试验 (MMA) 是一种体外试验，当没有血清学相容的血液时，它可以预测抗原阳性单位输血的结果。

材料和方法

54 名通过使用凝胶凝集的抗体筛选试验呈阳性的患者通过同种抗体鉴定小组进一步检查以确定同种抗体特异性。在确定和分类抗体后，使用 MMA 检查患者的样本以确定检测到的同种抗体的临床意义。我们还测试了 2 种接种方法（24 孔细胞培养板与 8 孔室载玻片）和 3 种可视化/染色技术（未染色相差、利什曼和吉姆萨染色）。

结果

54例中有35例（64.8%）单核细胞指数>5%，预示输血后发生溶血反应；23 例已知具有临床意义的抗体 [抗 C、抗 E、抗 C、抗 K、抗 Fy(a)、抗 Fy(b)、抗 JK(b)]，2 例具有抗-M 特异性，自身抗体 7 例，多重抗体 3 例。另一方面，研究中包括的 54 例 (35.2%) 病例中有 19 例显示单核细胞指数 <5%，这预示着输血后不存在溶血反应。8 孔室载玻片优于 24 孔培养板，因为后者在背景中显示出大量未吞噬的红细胞。此外，Leishman 染色优于 Giemsa 染色，在 RBC、单核细胞和吞噬泡之间有更好和更清晰的区分。

结论

在没有抗原阴性血液单位的情况下，MMA 可用作替代交叉匹配测试，用于选择血液单位。