MICA抗体监测在肾移植术后急、慢性排斥反应中的意义

Significance of MICA antibody monitoring in management of acute and chronic rejection after renal transplantation

目的探讨肾移植受者的抗MICA抗体水平与急性和陧性排斥反应的相关性及其对移植肾功能的影响。方法采用酶联免疫吸附方法检测接受同种异体肾移植手术的患者血清中MICA抗体，并同步检测HLA抗体、肾功血肌酐、尿量及移植肾超声等临床指标。本研究分两部分分别监测在肾移植术后急、慢性排斥反应中MICA抗体的变化。结果第一部分41例研究对象中有18例发生急性排斥反应，该组中MICA抗体阳性率高于肾功能稳定组（P〈0．05）；MICA抗体阳性组的急性排斥反应发生率高于MICA抗体阴性组（P〈0．05）；术后MICA抗体动态监测时发现，MICA抗体水平逐渐升高2～3d后出现排斥反应，给予抗排斥治疗后血肌酐水平逐渐降至正常，MICA抗体水平亦逐渐下降，但仍维持在阳性范围。第二部分40例患者中21例患者出现慢性排斥反应，其中MICA抗体阳性率明显高于肾功稳定组患者（P〈0．05）。慢排组中MICA抗体阳性患者的血肌酐与阴性组的血肌酐水平比较有统计学差异（P〈0．05）。移植肾穿刺病理结果显示MICA抗体阳性患者C4d沉积均为阳性。结论MICA抗体可预测急性排斥反应的发生及治疗效果，对于及时诊断及治疗排斥反应提供了一个重要指标，同时也是导致慢性排斥的主要因素之一，可影响移植肾的长期存活。

Objective To evaluate the association of major histocompatibility complex class I chain related gene A （MICA） antibodies with acute rejection （AR）, chronic rejection （CR） and renal function after renal transplantation. Methods Serum MICA antibodies were detected with ELISA before and after transplantation with also examinations of panel reactive antibodies （PRA）, serum creafinine, urine, graft ultrasound, lymphocyte subsets and the pathology of graft biopsy. The study was carried out in two parts to monitor MICA antibodies in acute and chronic rejections after renal transplantation. Results In the first part of the study 18 of the 41 recipients experienced episodes of acute rejection, and the incidence rate was markedly higher in MICA~ group than in MICA- group （P〈0.05）. Compared with the recipients with stable renal functions, the patients with acute graft rejection showed a significantly higher posifivity rate of MICA antibodies. Postoperative MICA antibody monitoring showed that MICA antibody level increased gradually 2-3 days after the occurrence of acute rejection; anti-rejection treatment lowered serum creatinine to a normal level but MICA antibodies remained positive. In the second part, 21 of 40 patients had chronic graft rejection and showed significantly higher positivity rate of MICA than the patients with stable renal functions （P〈0.05）. In patients with chronic rejections, the serum creatinine levels were significantly higher in MICA＋ than in MICA cases （P〈0.05）. Graft biopsy of all MICA＋ cases showed C4d deposition. Conclusion The status of MICA antibodies can predict the occurrence and treatment outcomes of acute rejection, and also as one of the major causes of chronic graft rejection, they affect the long-term survival of the renal grafts.