Hawkins P N, Lavender J P, Pepys M B
Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom.
N Engl J Med. 1990 Aug 23;323(8):508-13. doi: 10.1056/NEJM199008233230803.
In systemic amyloidosis the distribution and progression of disease have been difficult to monitor, because they can be demonstrated only by biopsy. Serum amyloid P component (SAP) is a normal circulating plasma protein that is deposited on amyloid fibrils because of its specific binding affinity for them. We investigated whether labeled SAP could be used to locate amyloid deposits.
Purified human SAP labeled with iodine-123 was given intravenously to 50 patients with biopsy-proved systemic amyloidosis--25 with the AL (primary) type and 25 with the AA (secondary) type--and to 26 control patients with disease and 10 healthy subjects. Whole-body images and regional views were obtained after 24 hours and read in a blinded fashion.
In the patients with amyloidosis the 123I-SAP was localized rapidly and specifically in amyloid deposits. The scintigraphic images obtained were characteristic and appeared to identify the extent of amyloid deposition in all 50 patients. There was no uptake of the 123I-SAP by the control patients and the healthy subjects. In all patients with AA amyloidosis the spleen was affected, whereas the scans showed uptake in the heart, skin, carpal region, and bone marrow only in patients with the AL type. Positive images were seen in six patients in whom biopsies had been negative or unsuccessful; in all six, amyloid was subsequently found on biopsy or at autopsy. Progressive amyloid deposition was observed in 9 of 11 patients studied serially.
Scintigraphy after the injection of 123I-SAP can be used for diagnosing, locating, and monitoring the extent of systemic amyloidosis.
在系统性淀粉样变性中，疾病的分布和进展一直难以监测，因为只有通过活检才能证实。血清淀粉样蛋白P成分（SAP）是一种正常循环血浆蛋白，因其对淀粉样纤维具有特异性结合亲和力而沉积在淀粉样纤维上。我们研究了标记的SAP是否可用于定位淀粉样沉积物。
将用碘-123标记的纯化人SAP静脉注射给50例经活检证实为系统性淀粉样变性的患者——25例为AL（原发性）型，25例为AA（继发性）型——以及26例患有其他疾病的对照患者和10名健康受试者。24小时后获得全身图像和局部视图，并采用盲法读取。
在淀粉样变性患者中，123I-SAP迅速且特异性地定位于淀粉样沉积物中。获得的闪烁图像具有特征性，似乎能识别所有50例患者中淀粉样沉积的范围。对照患者和健康受试者未摄取123I-SAP。在所有AA型淀粉样变性患者中，脾脏均受累，而扫描显示仅在AL型患者的心脏、皮肤、腕部区域和骨髓中有摄取。在6例活检为阴性或未成功的患者中可见阳性图像；在所有这6例患者中，随后在活检或尸检时发现了淀粉样蛋白。在11例接受连续研究的患者中，观察到9例有进行性淀粉样沉积。
注射123I-SAP后的闪烁扫描可用于诊断、定位和监测系统性淀粉样变性的范围。
