Laboratory of Clinical Chemistry, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium.
Clin Biochem. 2013 Jan;46(1-2):79-84. doi: 10.1016/j.clinbiochem.2012.09.023. Epub 2012 Oct 3.
Preliminary results of the IgA Hevylite™ assay including the establishment of the 95% reference interval and assessment of the specificity and sensitivity in different populations are reported.
The concentrations of IgA heavy and light chains (HLC) enabling to determine an IgAκ/IgAλ ratio were quantified in 119 apparently healthy individuals to generate 95% reference intervals. The specificity of this assay was assessed in 48 patients with an isolated polyclonal IgA increase. In a retrospective analysis of 68 patients with a monoclonal component type IgA (MC-IgA) identified by serum immunofixation (IFE), IgA HLC ratio values were compared with known results for serum protein electrophoresis (SPE) and free light chain (FLC) ratios.
The 95% reference range obtained in 119 controls (0.91-2.04) was close to that quoted by the manufacturer (0.80-2.04). Eight of the 48 patients (16.7%) with a polyclonal IgA increase had an IgA HLC ratio above the upper limit of the 95% reference interval. The IgA HLC ratio identified 65 (95.6%) among 68 patients with MC-IgA identified on the basis of IFE. For 34 of these patients (50%), MC-IgA was not detected by SPE due to its co-migration with alpha-2 or beta-globulins.
Compared with serum IFE, the IgA HLC ratio has a sensitivity of 95.6%. Further studies are needed to assess the specificity of the IgA HLC ratio in patients with an isolated polyclonal increase of serum IgA.
报告 IgA Hevylite™ 检测的初步结果，包括建立 95%参考区间以及在不同人群中评估其特异性和灵敏度。
为了生成 95%参考区间，我们对 119 名貌似健康的个体进行了 IgA 重链和轻链（HLC）浓度的定量检测，以确定 IgAκ/IgAλ比值。该检测方法的特异性在 48 例孤立性多克隆 IgA 升高的患者中进行了评估。在对通过血清免疫固定电泳（IFE）鉴定的 68 例单克隆成分 IgA（MC-IgA）患者的回顾性分析中，比较了 IgA HLC 比值与血清蛋白电泳（SPE）和游离轻链（FLC）比值的已知结果。
在 119 例对照者中获得的 95%参考范围（0.91-2.04）与制造商提供的参考范围（0.80-2.04）接近。48 例多克隆 IgA 升高患者中，有 8 例（16.7%）的 IgA HLC 比值超过 95%参考区间的上限。在基于 IFE 鉴定的 68 例 MC-IgA 患者中，IgA HLC 比值鉴定出 65 例（95.6%）。对于这些患者中的 34 例（50%），由于其与α-2 或β-球蛋白共迁移，SPE 未能检测到 MC-IgA。
与血清 IFE 相比，IgA HLC 比值的灵敏度为 95.6%。需要进一步研究来评估 IgA HLC 比值在孤立性血清 IgA 多克隆升高患者中的特异性。
