Department of Laboratory Medicine, KyungHee University School of Medicine, 892, Dongnam-ro, Gangdong-gu, Seooul, 05278, South Korea.
Department of Laboratory Medicine, KyungHee University Hospital at Gangdong, Seoul, South Korea.
Rheumatol Int. 2019 Aug;39(8):1423-1429. doi: 10.1007/s00296-019-04299-4. Epub 2019 Apr 10.
The dense fine speckled (DFS) nuclear pattern is one of the most common indirect immunofluorescence (IIF) patterns detected during routine anti-nuclear antibody (ANA) screening. There is a negative association between anti-DFS70 status and systemic autoimmune rheumatic disease (SARD), especially in the absence of concomitant SARD-specific autoantibodies. The purpose of this study was to determine the need for confirming anti-DFS70 status when a DFS pattern is observed in IIF-ANA. The frequency of anti-DFS70 detection on Western blot and the positive rate of connective tissue disease (CTD)-related autoantibody screening with a fluorescence-based enzyme immunoassay was evaluated in DFS (n = 182) and non-DFS (n = 359) groups. Specific autoantibodies against 15 autoantigens were identified by line immunoassay. We evaluated the frequency of cases of DFS mistaken for non-DFS and non-DFS cases mistaken for DFS, as well as the clinical impacts of these misinterpretations. Among cases of IIF-ANA with an observable DFS pattern, 68.1% had only anti-DFS70 without CTD-related autoantibodies, 20.3% were false positive for IIF-ANA, and the remaining 11.5% had CTD-related autoantibodies independent of anti-DFS70 status. These results indicated that CTD-related autoantibodies may be present with or without anti-DFS70 even if a DFS pattern is observed in IIF-ANA. Among patients who are ANA negative or have a low probability of SARD, an anti-DFS70 confirmation test has no clinical benefit and cannot replace specific tests for detecting CTD-related autoantibodies. Specific tests to detect CTD-related autoantibodies should be performed instead of anti-DFS70 confirmation tests when a DFS pattern is observed in IIF-ANA.
密集细点状（DFS）核型是常规抗核抗体（ANA）筛选中最常见的间接免疫荧光（IIF）模式之一。抗-DFS70 状态与系统性自身免疫性风湿病（SARD）之间存在负相关，尤其是在没有伴随的 SARD 特异性自身抗体的情况下。本研究旨在确定在 IIF-ANA 中观察到 DFS 模式时是否需要确认抗-DFS70 状态。评估了 DFS（n=182）和非 DFS（n=359）组的 Western blot 检测抗-DFS70 的频率以及基于荧光的酶免疫测定的结缔组织疾病（CTD）相关自身抗体筛查的阳性率。通过线免疫测定鉴定了针对 15 种自身抗原的特异性自身抗体。我们评估了将 DFS 误诊为非 DFS 和将非 DFS 误诊为 DFS 的病例频率，以及这些错误解释的临床影响。在具有可观察 DFS 模式的 IIF-ANA 病例中，68.1%仅具有抗-DFS70 而无 CTD 相关自身抗体，20.3%为 IIF-ANA 假阳性，其余 11.5%具有 CTD 相关自身抗体而与抗-DFS70 状态无关。这些结果表明，即使在 IIF-ANA 中观察到 DFS 模式，也可能存在 CTD 相关自身抗体，而无论是否存在抗-DFS70。在 ANA 阴性或 SARD 可能性较低的患者中，抗-DFS70 确认试验无临床获益，不能替代检测 CTD 相关自身抗体的特异性试验。当在 IIF-ANA 中观察到 DFS 模式时，应进行检测 CTD 相关自身抗体的特异性试验，而不是抗-DFS70 确认试验。
