Wada Hideo, Shiraki Katsuya, Matsumoto Takeshi, Suzuki Kei, Yamashita Yoshiki, Tawara Isao, Shimpo Hideto, Shimaoka Motomu
Department of General and Laboratory Medicine, Mie Prefectural General Medical Center, Yokkaichi 510-0885, Japan.
Department of Transfusion Medicine and Cell Therapy, Mie University Hospital, Tsu 514-8507, Japan.
J Clin Med. 2022 Oct 18;11(20):6142. doi: 10.3390/jcm11206142.
Although emicizumab is a bispecific, monoclonal antibody that has led to a significant improvement of treatment for hemophilia A patients with inhibitors, the routine monitoring of patients treated with emicizumab is difficult. Thrombin time (TT) reflects thrombin burst, which mainly depends on activation of factor V (FV) and FVIII.
We, therefore, developed a method for evaluating clotting activity independent of the presence of emicizumab. Normal plasma (NP) or FVIII-deficient plasma (FVIIIDP) with and without emicizumab was measured using clot waveform analysis (CWA)-activated partial thromboplastin time (APTT) and TT.
Emicizumab caused clot formation in FVIIIDP using the CWA-APTT; however, the coagulation peaks of plasma with and without emicizumab measured by the CWA-TT did not differ to a statistically significant extent. Regarding the mixing tests with NP and FVIIIDP, CWA-APTT showed large differences between each mixing test in plasma with and without emicizumab, whereas the CWA-TT showed similar patterns in mixing plasma with and without emicizumab. Regarding the standard curve of FVIII activity, the CWA-APTT showed an FVIII-concentration-dependent increase; however, the values with each concentration of FVIII differed between samples with and without emicizumab, whereas CWA-TT showed FVIII-concentration-dependent fluctuations independent of the presence of emicizumab, and the values with each concentration of FVIII were similar in samples with and without emicizumab.
As CWA-TT using a small amount of thrombin (0.5 IU/mL) can reflect thrombin burst and be useful for evaluating FVIII activity, independent of the presence of emicizumab, it is useful for monitoring clotting activity in patients with an anti-FVIII inhibitor treated with emicizumab.
尽管emicizumab是一种双特异性单克隆抗体，已使有抑制物的A型血友病患者的治疗有显著改善，但对接受emicizumab治疗的患者进行常规监测很困难。凝血酶时间（TT）反映凝血酶爆发，这主要取决于因子V（FV）和FVIII的激活。
因此，我们开发了一种独立于emicizumab存在来评估凝血活性的方法。使用凝血波形分析（CWA）激活的部分凝血活酶时间（APTT）和TT对添加和未添加emicizumab的正常血浆（NP）或FVIII缺乏血浆（FVIIIDP）进行检测。
使用CWA-APTT时，emicizumab在FVIIIDP中导致凝血形成；然而，通过CWA-TT测量，添加和未添加emicizumab的血浆的凝血峰在统计学上没有显著差异。关于NP和FVIIIDP的混合试验，CWA-APTT显示添加和未添加emicizumab的血浆在每次混合试验之间有很大差异，而CWA-TT在添加和未添加emicizumab的混合血浆中显示出相似模式。关于FVIII活性的标准曲线，CWA-APTT显示出FVIII浓度依赖性增加；然而，添加和未添加emicizumab的样本中，每种FVIII浓度的值有所不同，而CWA-TT显示出FVIII浓度依赖性波动，与emicizumab的存在无关，并且添加和未添加emicizumab的样本中每种FVIII浓度的值相似。
由于使用少量凝血酶（0.5 IU/mL）的CWA-TT可以反映凝血酶爆发，并且可用于评估FVIII活性，独立于emicizumab的存在，因此它对于监测接受emicizumab治疗的有抗FVIII抑制物患者的凝血活性很有用。
