Allergy and Immunology Unit, Azienda Ospedaliera San Maria degli Angeli, Pordenone, Italy.
Clin Chem. 2010 Mar;56(3):464-8. doi: 10.1373/clinchem.2009.128132. Epub 2009 Dec 18.
Assays for IgG antibodies against deamidated gliadin (IgG-anti-dGli) are comparable in performance with tests detecting IgA antibodies against tissue transglutaminase (IgA-anti-tTG) in diagnosing celiac disease (CD). IgA-anti-tTG are absent in IgA deficiency, a condition often associated with CD. In IgA deficiency, IgG-anti-tTG, which have a lower overall diagnostic accuracy, are routinely measured. We examined whether IgG-anti-dGli would be useful for diagnosing CD in patients with IgA deficiency.
We studied 34 IgA-deficient CD patients, 185 IgA-competent newly diagnosed children with CD, 316 children without CD, 400 adult blood donors, and 6 control IgA-deficient individuals without CD. Anti-dGli and anti-tTG were measured by ELISA, and endomysium antibodies (EmA) were measured by immunofluorescence on monkey esophagus (IgA as well as IgG class for all antibodies). We calculated diagnostic sensitivity (percentage of patients above cutoff with 95% CIs) according to age-specific cutoffs for 95% diagnostic specificity and according to cutoffs proposed by the manufacturer of the assays.
No IgA-deficient CD patients were positive for any IgA-based antibody assay. Diagnostic sensitivity of IgG-anti-tTG was 91.2% (95% CI 76.3%-97.7%) according to age-specific cutoffs and 82.4% (66.1%-92.0%) according to manufacturer cutoffs. The diagnostic sensitivity of IgG-EmA was 75.8% (58.8%-87.4%) and the sensitivity of IgG-anti-dGli was 88.2% (72.8%-95.9%) according to both cutoffs.
IgG-anti-dGli and IgG-anti-tTG have comparable diagnostic sensitivities for IgA-deficient celiac patients. IgG-anti-dGli may be useful for diagnosing CD in IgA-deficient patients.
针对脱酰胺麦胶蛋白的 IgG 抗体（IgG-抗-dGli）检测与组织转谷氨酰胺酶 IgA 抗体（IgA-抗-tTG）检测在诊断乳糜泻（CD）方面具有相当的性能。在 IgA 缺乏症中，不存在 IgA-抗-tTG，而这种情况通常与 CD 相关。在 IgA 缺乏症中，通常会测量具有较低整体诊断准确性的 IgG-抗-tTG。我们研究了 IgG-抗-dGli 是否可用于诊断 IgA 缺乏症患者的 CD。
我们研究了 34 名 IgA 缺乏的 CD 患者、185 名新诊断的 IgA 正常的 CD 儿童、316 名无 CD 的儿童、400 名成年献血者和 6 名无 CD 的对照 IgA 缺乏个体。通过 ELISA 检测抗-dGli 和抗-tTG，通过猴食管免疫荧光法检测内肌膜抗体（EmA）（所有抗体的 IgA 以及 IgG 类别）。我们根据 95%特异性的年龄特异性截断值和检测试剂盒制造商推荐的截断值计算了诊断敏感性（超过截断值的患者百分比及其 95%置信区间）。
没有 IgA 缺乏的 CD 患者对任何基于 IgA 的抗体检测均呈阳性。根据年龄特异性截断值，IgG-抗-tTG 的诊断敏感性为 91.2%（95%CI 76.3%-97.7%），根据制造商截断值为 82.4%（66.1%-92.0%）。IgG-EmA 的诊断敏感性为 75.8%（58.8%-87.4%），IgG-抗-dGli 的诊断敏感性为 88.2%（72.8%-95.9%），两个截断值均如此。
IgG-抗-dGli 和 IgG-抗-tTG 对 IgA 缺乏的乳糜泻患者具有相当的诊断敏感性。IgG-抗-dGli 可能有助于诊断 IgA 缺乏的 CD 患者。
