Introduction

The appearance of de novo donor-specific anti-human leukocyte antigen antibodies (dnDSAs) after kidney transplantation is independently associated with poor long-term allograft outcomes. The objective of the present study was to evaluate the predictive value of a flow cytometry crossmatching (FC-XM) assay after the appearance of dnDSAs related to antibody-mediated allograft rejection (ABMR) after kidney transplantation.

Materials and methods

A total of 89 recipients with dnDSAs after transplantation were included. The crossmatching results were compared with the dnDSA profile (the mean fluorescence intensity (MFI), the complement-binding activity, and the IgG subclass profile) and the biopsy's morphological features.

Results

Of the 89 patients, 59 (66%) were positive in an FC-XM assay, 17 (19%) had complement-binding DSAs, 55 (62%) were positive for IgG1 and/or IgG3 in a solid phase assay, and 45 (51%) had morphological biopsy features linked to ABMR.

Conclusion

An FC-XM assay was unable to discriminate between cases with or without ABMR on biopsy findings; it had a low positive predictive value (<70%) and a low negative positive predictive value (<42.9%), taking into account the sensitivity of our assay (limit of detection: DSAs with an MFI >3000). In this context, the height of the MFI of the dnDSAs might be enough for a high positive predictive value for ABMR and additional testing for complement binding activity can remain optional.

中文翻译：

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流式细胞术交叉匹配研究开发新的供体特异性抗体的患者的肾脏活检证实，抗体介导的排斥反应。

介绍

肾移植后从头供体特异性抗人白细胞抗原抗体（dn DSA）的出现与长期同种异体移植的不良结果独立相关。本研究的目的是评估与肾脏移植后抗体介导的同种异体移植排斥反应（ABMR）相关的dn DSA出现后，流式细胞术交叉匹配（FC-XM）分析的预测价值。

材料和方法

包括89位dnDSA移植患者。将交叉匹配结果与dn DSA图谱（平均荧光强度（MFI），补体结合活性和IgG亚类图谱）和活检的形态特征进行比较。

结果

在这89例患者中，FC-XM分析中59例（66％）阳性，固相分析中17例（19％）的补体结合DSA阳性，55例（62％）IgG1和/或IgG3阳性。 45（51％）具有与ABMR相关的形态学活检特征。

结论

FC-XM分析无法区分活检结果有无ABMR的病例。考虑到我们测定的灵敏度（检测限：MFI> 3000的DSA），它的阳性预测值低（<70％）和阴性阴性预测值低（<42.9％）。在这种情况下，dn DSA的MFI高度可能足以获得ABMR的高阳性预测值，并且补体结合活性的其他测试仍然是可选的。