Loock Clemens Dario, Egerer Karl, Feist Eugen, Burmester Gerd-Rüdiger
Department of Rheumatology and Clinical Immunology of the Charité, Universitätsmedizin Berlin, Berlin, Germany.
Labor Berlin GmbH, Berlin, Germany.
RMD Open. 2017 Apr 24;3(1):e000409. doi: 10.1136/rmdopen-2016-000409. eCollection 2017.
Visual evaluation of indirect immunofluorescence (IIF) on human epithelial-2 cells is the routine method for screening for antinuclear antibodies (ANA) in connective tissue diseases. Since visual IIF is time-consuming and subjective, automated IIF processors have been developed to offer standardised, valid and cost-efficient IIF assays.
The aim of this study was to determine the diagnostic reliability of 2 widely used IIF processors (Aklides, Medipan GmbH and Helios, Aesku Diagnostics) under real-life laboratory working conditions.
ANA were determined in samples from patients with suspected autoimmune rheumatic disease (n=1008) using both automated IIF processors and compared with the results obtained by visual interpretation. The performance of IIF processors to discriminate positive from negative samples, pattern recognition and end point titre prediction were evaluated.
The IIF processors showed moderate agreement with visual interpretation in discriminating positive from negative ANA samples (κ values: Aklides 0.494; Helios 0.415). The sensitivity/specificity was 89%/59% for Aklides and 87%/54% for Helios. However, both processors correctly identified 99% of definitely positive samples (titre ≥1:320). Aklides correctly identified 43% of fluorescence patterns and its light intensity values showed good correlation (Spearman's ρ=0.680) with visually obtained titres.
Automated IIF determination under real-life laboratory working conditions remains a challenge. Owing to their high sensitivity at clinically relevant ANA titres, automated IIF processors can already support but not totally replace visual IIF.
在人上皮2细胞上进行间接免疫荧光（IIF）的视觉评估是结缔组织病中抗核抗体（ANA）筛查的常规方法。由于视觉IIF既耗时又主观，因此已开发出自动化IIF处理器以提供标准化、有效且具有成本效益的IIF检测。
本研究的目的是在实际实验室工作条件下确定2种广泛使用的IIF处理器（Aklides，Medipan GmbH公司；Helios，Aesku Diagnostics公司）的诊断可靠性。
使用这两种自动化IIF处理器对疑似自身免疫性风湿病患者（n = 1008）的样本进行ANA检测，并将结果与视觉判读获得的结果进行比较。评估了IIF处理器区分阳性和阴性样本、模式识别以及终点滴度预测的性能。
在区分ANA阳性和阴性样本方面，IIF处理器与视觉判读显示出中等一致性（κ值：Aklides为0.494；Helios为0.415）。Aklides的灵敏度/特异性为89%/59%，Helios为87%/54%。然而，两种处理器都正确识别了99%的明确阳性样本（滴度≥1:320）。Aklides正确识别了43%的荧光模式，其光强度值与视觉获得的滴度显示出良好的相关性（Spearman's ρ = 0.680）。
在实际实验室工作条件下进行自动化IIF检测仍然是一项挑战。由于自动化IIF处理器在临床相关ANA滴度下具有高灵敏度，它们已经可以提供支持，但不能完全取代视觉IIF。
