Gmeiner Stopar Tanja, Fettich Jure, Zver Samo, Mlinaric-Rascan Irena, Hojker Sergej, Socan Aljaz, Peitl Petra Kolenc, Mather Stephen
Department for Nuclear Medicine, University Medical Centre Ljubljana, Slovenia.
Nucl Med Commun. 2008 Dec;29(12):1059-65. doi: 10.1097/MNM.0b013e3283134d6e.
This study was performed to explore the possibility of using Tc-rituximab as an imaging agent to assess expression of CD20 antigen in patients with B-cell non-Hodgkin's lymphoma (NHL) before (radio) immunotherapy, for staging and subsequent evaluation of remission of NHL.
Rituximab was purified from Mabthera and photoactivated by ultraviolet light. The irradiated solution was aliquoted and labelled with pertechnetate. The effectiveness of the labelling method was evaluated by determination of the number of free thiol groups per photoreduced antibody, radiochemical purity determination and in-vitro stability. Immunoreactivity of Tc-rituximab was assessed on Ramos cells using a direct binding assay. Ten patients (age 31-70 years, mean 50 years) were included, nine with CD20 B-cell NHL and one with CD20-NHL. Whole-body and single photon emission computed tomography images were taken 1, 3, 6 and 20 h postinjection of Tc-rituximab. Scintigraphic results were compared with computerized tomography (CT) findings.
In all cases radiochemical purity over 95% was observed with preserved affinity for CD20 antigen. In all patients expected activity was seen in the blood pool, liver, kidneys and spleen. Pathological, moderately to markedly increased Tc-rituximab activity was seen in all but one CT-confirmed NHL involved sites 6 and 20 h postinjection. In one patient, increased activity of Tc-rituximab was additionally seen in one region not seen on CT. In three patients increased accumulation was seen in bone marrow.
Tc-rituximab is a promising imaging agent suitable for assessing expression of CD20 in patients with NHL before (radio) immunotherapy.
本研究旨在探讨使用锝标记利妥昔单抗作为成像剂，在B细胞非霍奇金淋巴瘤（NHL）患者进行（放射）免疫治疗前评估CD20抗原表达、进行NHL分期及随后评估缓解情况的可能性。
从美罗华纯化利妥昔单抗，并用紫外线进行光活化。将辐照后的溶液分装并与高锝酸盐标记。通过测定每个光还原抗体的游离巯基数量、放射化学纯度测定和体外稳定性来评估标记方法的有效性。使用直接结合试验在拉莫斯细胞上评估锝标记利妥昔单抗的免疫反应性。纳入10例患者（年龄31 - 70岁，平均50岁），其中9例为CD20 B细胞NHL，1例为CD20 - NHL。在注射锝标记利妥昔单抗后1、3、6和20小时拍摄全身和单光子发射计算机断层扫描图像。将闪烁扫描结果与计算机断层扫描（CT）结果进行比较。
在所有病例中观察到放射化学纯度超过95%，且对CD20抗原的亲和力得以保留。在所有患者中，在血池、肝脏、肾脏和脾脏中均可见预期活性。在除1例之外的所有CT确诊的NHL受累部位，注射后6和20小时可见病理性的、中度至明显增加的锝标记利妥昔单抗活性。在1例患者中，在CT上未见的一个区域也额外观察到锝标记利妥昔单抗活性增加。在3例患者中，骨髓中可见活性增加。
锝标记利妥昔单抗是一种有前景的成像剂，适用于在（放射）免疫治疗前评估NHL患者的CD20表达。
