Spuriously Low Serum IgG4 Concentrations Caused by the Prozone Phenomenon in Patients With IgG4-Related Disease
Spuriously Low Serum IgG4 Concentrations Caused by the Prozone Phenomenon in Patients With IgG4-Related Disease
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DOI：
10.1002/art.38193
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发表时间：
2014-01-01
影响因子：
13.3
通讯作者：
Stone, John H.
中科院分区：
文献类型：
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作者：
Khosroshahi, Arezou;Cheryk, Lynn A.;Stone, John H.
Objective.确定IgG 4相关疾病（IgG 4-RD）患者中前带效应的频率。在鉴定IgG 4-RD索引患者中的前带效应后，我们检查了其他样本以确定该现象的频率。重新检测了从之前报告过结果的IgG 4-RD患者中获得的38份血清样本。将重复分析测定的血清IgG 4浓度与最初报道的值进行比较。在38例患者中的10例（26%）中，最初报告的IgG 4值假性偏低;在这10例样本中均发现了前带效应。通过样品稀释校正前带效应导致10份样品中平均血清IgG 4浓度从26 mg/dl修订为2，008 mg/dl（正常范围2.4-121 mg/dl）。所有10例样本受前带效应影响的患者均具有活性IgG 4-RD。未能检测到血清IgG 4浓度升高对这些患者不进行治疗的决定有直接影响。前带效应可能导致IgG 4-RD患者的IgG 4浓度被严重低估，并为某些患者的疾病活动性和血清IgG 4水平之间观察到的相关性较差提供了可能的解释。如果血清IgG 4测量结果与临床病理诊断和疾病活动性的临床评估不一致，则应考虑这种现象。
Objective. To determine the frequency of the prozone effect in patients with IgG4-related disease (IgG4-RD).Methods. After identifying the prozone effect in an index patient with IgG4-RD, we examined additional samples to determine the frequency of this phenomenon. Thirty-eight serum samples obtained from patients with IgG4-RD whose results had been reported previously were retested. The serum IgG4 concentrations determined by this repeat analysis were compared with the originally reported values.Results. In 10 (26%) of 38 patients, the originally reported IgG4 values were falsely low; the prozone effect was identified in each of these 10 samples. Correction of the prozone effect by sample dilution led to revision of the mean serum IgG4 concentration in the 10 samples, from 26 mg/dl to 2,008 mg/dl (normal range 2.4-121 mg/dl). All 10 patients whose samples were affected by the prozone effect had active IgG4-RD. Failure to detect the elevated serum IgG4 concentrations had a direct impact on the decision not to institute treatment in these patients.Conclusion. The prozone effect may lead to major underestimations of IgG4 concentrations in patients with IgG4-RD and offers a potential explanation for the poor correlation observed between disease activity and serum IgG4 levels in some patients. This phenomenon should be considered if the serum IgG4 measurement appears discordant with the clinicopathologic diagnosis and the clinical assessment of disease activity.