Healy David G, Watson R William G, O'Keane Conor, Egan Jim J, McCarthy James F, Hurley John, Fitzpatrick John, Wood Alfred E
Prof Eoin O'Malley National Centre for Cardiothoracic Surgery, Mater Misericordiae University Hospital, Dublin, Ireland.
Eur J Cardiothorac Surg. 2006 May;29(5):760-6. doi: 10.1016/j.ejcts.2006.01.065. Epub 2006 Apr 17.
Transplant rejection remains a clinical problem despite therapies that focus on lymphocyte suppression, with little attention focused on the neutrophil. Neutrophils are however the first leukocyte to infiltrate the allograft, are capable of causing myocardial damage and may facilitate lymphocytes recruitment. We hypothesised that an early allograft neutrophil infiltration influences rejection severity.
Myocardial neutrophil infiltration was assessed using CD15 and myeloperoxidase immunohistochemistry of rejection surveillance endomyocardial biopsy specimens from human cardiac transplant recipients (n=18). In patients undergoing cardiac transplantation (n=10), neutrophils were isolated from multiple perioperative blood samples using a ficoll-based density gradient centrifugation method. The expression of the neutrophil adhesion protein CD11b was then assessed using flow cytometry and compared to subsequent endomyocardial biopsy rejection grades. The effects of contemporary immunosuppressive agents on human neutrophil CD11b were also assessed using healthy control volunteers.
Myeloperoxidase staining of endomyocardial biopsies from human heart transplant recipients demonstrated a positive correlation between the degree of neutrophil infiltration and rejection severity at the first postoperative biopsy. Rejection severity was unrelated to ischaemic time. Functional assessment of neutrophils obtained from recipients was then performed. Perioperative transplant sampling demonstrated a significant correlation between the preoperative expression of CD11b and rejection grade at the first postoperative biopsy. In addition, dynamic changes in CD11b expression in the first 24 h positively correlated with subsequent rejection severity. In vitro experiments showed that transplant immunosuppression did not alter neutrophil CD11b expression.
This study demonstrates a potentially greater role for neutrophils in cardiac transplantation than previously recognised, and suggests that blockade of the early allograft neutrophil infiltration might prevent subsequent lymphocyte recruitment and attenuate rejection.
尽管有针对淋巴细胞抑制的治疗方法，但移植排斥反应仍然是一个临床问题，而对中性粒细胞的关注较少。然而，中性粒细胞是最早浸润同种异体移植物的白细胞，能够导致心肌损伤，并可能促进淋巴细胞的募集。我们假设同种异体移植物早期的中性粒细胞浸润会影响排斥反应的严重程度。
使用CD15和髓过氧化物酶免疫组织化学方法，对18例人类心脏移植受者的排斥反应监测心内膜活检标本进行心肌中性粒细胞浸润评估。在10例接受心脏移植的患者中，采用基于菲可的密度梯度离心法从多个围手术期血样中分离中性粒细胞。然后使用流式细胞术评估中性粒细胞黏附蛋白CD11b的表达，并与随后的心内膜活检排斥反应分级进行比较。还使用健康对照志愿者评估了当代免疫抑制剂对人中性粒细胞CD11b的影响。
人类心脏移植受者的心内膜活检标本的髓过氧化物酶染色显示，术后首次活检时中性粒细胞浸润程度与排斥反应严重程度呈正相关。排斥反应严重程度与缺血时间无关。然后对从受者获得的中性粒细胞进行功能评估。围手术期移植样本显示，术前CD11b表达与术后首次活检时的排斥反应分级之间存在显著相关性。此外，最初24小时内CD11b表达的动态变化与随后的排斥反应严重程度呈正相关。体外实验表明，移植免疫抑制并未改变中性粒细胞CD11b的表达。
本研究表明中性粒细胞在心脏移植中的作用可能比以前认识到的更大，并表明阻断同种异体移植物早期的中性粒细胞浸润可能会阻止随后的淋巴细胞募集并减轻排斥反应。
