Department of Rheumatology, Peijas Hospital, Helsinki University Central Hospital, Vantaa 01400, Finland.
Rheumatol Int. 2012 Aug;32(8):2445-51. doi: 10.1007/s00296-011-1962-3. Epub 2011 Jun 26.
Associations of different assays for antibodies to C1q (anti-C1q) and to dsDNA (anti-dsDNA) and of complements C3 and C4 with disease activity in patients with systemic lupus erythematosus (SLE) were studied. The clinical manifestations of 223 SLE patients were recorded, and the disease activity was assessed by the SLEDAI score. Anti-C1q were determined by two enzyme-linked immunosorbent assays (ELISA) and anti-dsDNA by a radioimmunoassay (RIA), a Crithidia immunofluorescence (IF) assay and three ELISA assays using human telomere DNA, plasmid DNA circles, or calf thymus DNA as antigens, respectively. Complement C3 and C4 were determined by nephelometry. Control sera were obtained from 98 blood donors. In patients with SLE, the prevalence of anti-C1q was 17-18% and that of anti-dsDNA was 36-69%. Anti-C1q, anti-dsDNA, and complement C3 and C4 correlated well with the overall activity of SLE (r = 0.323-0.351, 0.353-0.566, and -0.372-0.444, respectively; P < 0.001). Sensitivity, specificity, positive predictive value, and negative predictive value for active lupus nephritis among SLE patients were 40-44, 92, 29, and 91-92% for anti-C1q and 48-68, 29-66, 11-16, and 86-91% for anti-dsDNA, respectively. Patients with active nephritis had higher levels of anti-C1q and lower levels of C3 and C4 than patients with inactive nephritis (P = 0.003-0.018). The corresponding associations of anti-dsDNA were somewhat weaker (P = 0.023-0.198). Hematological parameters reflecting disease activity correlated clearly better with anti-dsDNA and complement C3 and C4 than with anti-C1q. Anti-C1q is inferior to anti-dsDNA as a diagnostic test in SLE and in the evaluation of overall clinical activity of the disease. Anti-C1q together with complement C3 and C4 may offer useful additional information to monitor lupus nephritis activity. There are no practical differences between different assays for anti-C1q and anti-dsDNA.
研究了抗 C1q（抗-C1q）和抗双链 DNA（抗-dsDNA）抗体以及补体 C3 和 C4 在系统性红斑狼疮（SLE）患者中的不同检测方法与疾病活动的关系。记录了 223 例 SLE 患者的临床表现，并通过 SLEDAI 评分评估疾病活动。抗-C1q 采用两种酶联免疫吸附测定法（ELISA）测定，抗-dsDNA 采用放射免疫测定法（RIA）、克氏锥虫免疫荧光（IF）测定法和三种 ELISA 测定法，分别用人端粒 DNA、质粒 DNA 环或小牛胸腺 DNA 作为抗原。补体 C3 和 C4 采用散射比浊法测定。对照血清取自 98 名献血者。在 SLE 患者中，抗-C1q 的患病率为 17-18%，抗-dsDNA 的患病率为 36-69%。抗-C1q、抗-dsDNA 以及补体 C3 和 C4 与 SLE 的整体活动密切相关（r = 0.323-0.351、0.353-0.566 和-0.372-0.444，均 P<0.001）。在 SLE 患者中，抗-C1q 对活动性狼疮肾炎的敏感性、特异性、阳性预测值和阴性预测值分别为 40-44%、92%、29%和 91-92%，抗-dsDNA 分别为 48-68%、29-66%、11-16%和 86-91%。与无活动的肾炎患者相比，有活动的肾炎患者的抗-C1q 水平较高，而 C3 和 C4 水平较低（P=0.003-0.018）。抗-dsDNA 的相应相关性则稍弱（P=0.023-0.198）。反映疾病活动的血液学参数与抗-dsDNA 和补体 C3 和 C4 的相关性明显优于抗-C1q。抗-C1q 作为 SLE 的诊断试验和评估疾病的整体临床活动均不如抗-dsDNA。抗-C1q 与补体 C3 和 C4 联合可能提供监测狼疮肾炎活动的有用信息。不同的抗-C1q 和抗-dsDNA 检测方法之间没有实际差异。
