University Department of Pathology, Western Infirmary, Glasgow, UK.
Clin Exp Immunol. 2010 Dec;162(3):516-27. doi: 10.1111/j.1365-2249.2010.04264.x. Epub 2010 Oct 21.
The precise biological mechanisms that caused the TGN1412 clinical trial tragedy (also known as 'The Elephant Man Clinical Trial') in March 2006 remain a mystery to this day. It is assumed widely that the drug used in this trial (TGN1412) bound to CD28 on T lymphocytes and following activation of these cells, a massive 'cytokine storm' ensued, leading ultimately to multi-organ failure in all recipients. The rapidity of this in vivo response (within 2 h), however, does not fit well with a classical T lymphocyte response, suggesting that other 'faster-acting' cell types may have been involved. In this study we have activated purified human peripheral blood leucocyte populations using various clones of mouse monoclonal anti-CD28 presented to cells in the form of a multimeric array. Cytokines were measured in cell-free supernatants at 2 h, and specific mRNA for tumour necrosis factor (TNF)-α, thought to be the initiator of the cytokine storm, was also measured in cell lysates by reverse transcription-polymerase chain reaction (RT-PCR). Monocytes were the only cell type found to show significant (P < 0·05) up-regulation of TNF-α at 2 h. Eleven other monocyte cytokines were also up-regulated by anti-CD28 within this time-frame. It therefore seems likely that monocytes and not T cells, as widely believed, were probably responsible, at least in part, for initiating the cytokine storm. Furthermore, we propose that a multimeric antibody array may have formed in vivo on the vascular endothelium via an interaction between TGN1412 and CD64 (FcγRI), and we provide some evidence in support of this hypothesis.
导致 2006 年 3 月 TGN1412 临床试验悲剧（也称为“象人临床试验”）的确切生物学机制至今仍是个谜。人们普遍认为，该试验中使用的药物（TGN1412）与 T 淋巴细胞上的 CD28 结合，随后这些细胞被激活，引发大规模的“细胞因子风暴”，最终导致所有接受者的多器官衰竭。然而，这种体内反应的速度（在 2 小时内）与经典的 T 淋巴细胞反应不太吻合，这表明可能涉及其他“作用更快”的细胞类型。在这项研究中，我们使用各种形式的多聚体阵列将小鼠单克隆抗 CD28 克隆递呈给细胞，以激活纯化的人外周血白细胞群体。在 2 小时时测量细胞因子在无细胞上清液中的浓度，并通过逆转录聚合酶链反应 (RT-PCR) 在细胞裂解物中测量肿瘤坏死因子 (TNF)-α 的特异性 mRNA，认为它是细胞因子风暴的启动子。只有单核细胞显示出在 2 小时时 TNF-α 的显著（P < 0·05）上调。在这段时间内，其他 11 种单核细胞细胞因子也被抗 CD28 上调。因此，单核细胞而不是 T 细胞（如广泛认为的那样）可能至少部分负责引发细胞因子风暴。此外，我们提出多聚体抗体阵列可能通过 TGN1412 与 CD64（FcγRI）之间的相互作用在血管内皮细胞中形成体内，并且我们提供了一些支持该假设的证据。
