Frontroth Juan Pablo, Favaloro Emmanuel J
Laboratorio de Hemostasia y Trombosis, Hospital de Pediatría "Prof. Dr. Juan P. Garrahan", Buenos Aires, C1245AAM, Argentina.
Haematology Department, Sydney Centres for Thrombosis and Haemostasis, Institute of Clinical Pathology and Medical Research (ICPMR), Westmead Hospital, NSW Health Pathology, Westmead, NSW, 2145, Australia.
Methods Mol Biol. 2017;1646:473-494. doi: 10.1007/978-1-4939-7196-1_35.
Ristocetin-induced platelet aggregation (RIPA) is used as an in vitro test to determine the presence and integrity of the platelet glycoprotein (GP) Ibα-V-IX complex and von Willebrand factor (VWF) interaction and is usually performed using platelet-rich plasma (PRP). Impairment in the response of VWF/GPIbα-V-IX is measured with reference to several established concentrations of ristocetin and may indicate defects in VWF or in GPIbα-V-IX function. RIPA-based mixing studies comprise an additional approach to testing this interaction to help define whether defects identified by RIPA lie in VWF or in GPIbα-V-IX. For example, the correction of an abnormal RIPA trace after mixing PRP with normal plasma and rechallenging with ristocetin at 1.0 mg/mL suggests VWF function/quantity defect. RIPA mixing studies at lower doses of ristocetin (0.5 mg/mL) are recommended for discrimination of von Willebrand disease type 2B (VWD2B) from the rarer platelet-type (PT) VWD and for the phenotypic laboratory diagnosis of VWD2B. The demonstration of a plasma factor capable of inducing platelet aggregation at such low doses of ristocetin represents the hallmark for the phenotypic laboratory diagnosis of VWD2B. Moreover, since both VWD2B and PT-VWD may present with thrombocytopenia, RIPA-based mixing studies are also useful in thrombocytopenic patients in whom RIPA testing is difficult to assess.
瑞斯托霉素诱导的血小板聚集（RIPA）用作体外试验，以确定血小板糖蛋白（GP）Ibα-V-IX复合物与血管性血友病因子（VWF）相互作用的存在和完整性，通常使用富血小板血浆（PRP）进行。参照几种既定浓度的瑞斯托霉素来测量VWF/GPIbα-V-IX反应的损害，这可能表明VWF或GPIbα-V-IX功能存在缺陷。基于RIPA的混合研究是测试这种相互作用的另一种方法，有助于确定RIPA检测到的缺陷是存在于VWF还是GPIbα-V-IX中。例如，将PRP与正常血浆混合，然后用1.0mg/mL瑞斯托霉素再次刺激后，异常RIPA曲线得到校正，提示VWF功能/数量缺陷。推荐使用较低剂量瑞斯托霉素（0.5mg/mL）进行RIPA混合研究，以区分2B型血管性血友病（VWD2B）与罕见的血小板型（PT）VWD，并用于VWD2B的表型实验室诊断。在如此低剂量瑞斯托霉素下能够诱导血小板聚集的血浆因子的证明是VWD2B表型实验室诊断的标志。此外，由于VWD2B和PT-VWD都可能出现血小板减少，基于RIPA的混合研究对于RIPA检测难以评估的血小板减少患者也很有用。
