Northwestern University Feinberg School of Medicine, Chicago, Illinois.
Exagen, Inc., Vista, California.
Arthritis Rheumatol. 2020 Jan;72(1):78-88. doi: 10.1002/art.41093. Epub 2019 Nov 25.
To evaluate the frequency of cell-bound complement activation products (CB-CAPs) as a marker of complement activation in patients with suspected systemic lupus erythematosus (SLE) and the usefulness of this biomarker as a predictor of the evolution of probable SLE into SLE as classified by the American College of Rheumatology (ACR) criteria.
Patients in whom SLE was suspected by lupus experts and who fulfilled 3 ACR classification criteria for SLE (probable SLE) were enrolled, along with patients with established SLE as classified by both the ACR and the Systemic Lupus International Collaborating Clinics (SLICC) criteria, patients with primary Sjögren's syndrome (SS), and patients with other rheumatic diseases. Individual CB-CAPs were measured by flow cytometry, and positivity rates were compared to those of commonly assessed biomarkers, including serum complement proteins (C3 and C4) and autoantibodies. The frequency of a positive multianalyte assay panel (MAP), which includes CB-CAPs, was also evaluated. Probable SLE cases were followed up prospectively.
The 92 patients with probable SLE were diagnosed more recently than the 53 patients with established SLE, and their use of antirheumatic medications was lower. At the enrollment visit, more patients with probable SLE were positive for CB-CAPs (28%) or MAP (40%) than had low complement levels (9%) (P = 0.0001 for each). In probable SLE, MAP scores of >0.8 at enrollment predicted fulfillment of a fourth ACR criterion within 18 months (hazard ratio 3.11, P < 0.01).
Complement activation occurs in some patients with probable SLE and can be detected with higher frequency by evaluating CB-CAPs and MAP than by assessing traditional serum complement protein levels. A MAP score above 0.8 predicts transition to classifiable SLE according to ACR criteria.
评估细胞结合补体激活产物（CB-CAPs）作为疑似系统性红斑狼疮（SLE）患者补体激活标志物的频率，以及该生物标志物作为预测可能 SLE 向美国风湿病学会（ACR）标准分类的 SLE 发展的有用性。
纳入由狼疮专家怀疑患有 SLE 且符合 SLE 的 3 项 ACR 分类标准（可能 SLE）的患者，以及同时符合 ACR 和国际系统性红斑狼疮协作临床（SLICC）标准分类的确诊 SLE 患者、原发性干燥综合征（SS）患者和其他风湿病患者。通过流式细胞术测量个体 CB-CAPs，并将阳性率与包括血清补体蛋白（C3 和 C4）和自身抗体在内的常用评估生物标志物进行比较。还评估了包括 CB-CAPs 在内的多分析物检测试剂盒（MAP）的阳性频率。对可能 SLE 病例进行前瞻性随访。
92 例可能 SLE 患者的诊断时间晚于 53 例确诊 SLE 患者，且抗风湿药物的使用频率较低。在入组时，更多可能 SLE 患者的 CB-CAPs（28%）或 MAP（40%）呈阳性，而补体水平较低（9%）（每种情况 P = 0.0001）。在可能 SLE 中，入组时 MAP 评分>0.8 预测在 18 个月内满足第 4 项 ACR 标准（危险比 3.11，P < 0.01）。
在一些可能 SLE 患者中存在补体激活，通过评估 CB-CAPs 和 MAP 比评估传统的血清补体蛋白水平更能频繁地检测到。MAP 评分>0.8 预测根据 ACR 标准向可分类 SLE 的转变。
