Department of Laboratory Medicine, Biochemistry Laboratory, Riuniti Hospital, Bergamo, Italy.
J Pediatr Gastroenterol Nutr. 2012 Jul;55(1):44-9. doi: 10.1097/MPG.0b013e3182470249.
Positivity of both immunoglobulin A anti-tissue transglutaminase (TTG) and anti-endomysium antibodies (EMA) has a positive predictive value of nearly 100% for celiac disease (CD). The objective of the present study was to evaluate whether patients of any age, with high pretest probability of CD and high titre of anti-TTG and EMA positivity, have a high probability of intestinal damage and may not require the biopsy for final diagnosis.
A retrospective analysis of 412 consecutively referred patients, age range 10 months to 72 years, who underwent small-bowel biopsy for suspicion of CD and positivity to both anti-TTG and EMA, was performed at 4 Italian centers. Biopsies were evaluated independently by 2 pathologists using Marsh modified classification; in cases of dissimilar results, a third pathologist examined the biopsy. The final histological finding diagnosis was expressed as the prevalent or highest score assigned by the pathologist board.
Three hundred ninety-six patients (96.1%) had histological findings consistent with CD (grade 2 and 3a, 3b, or 3c of modified Marsh classification). An anti-TTG ratio ≥ 7 was able to identify with the 3 assays used (Celikey, anti-TTG immunoglobulin A, EuTTG) all of the patients with significant mucosal damage (Marsh ≥ 2) independent of age and sex; specificity and positive predictive value were 100%. An anti-TTG ratio >20 was more specific (99.8%) for identification of patients with villous atrophy (Marsh 3 a, b, or c).
Patients with positivity of anti-TTG ≥ 7-fold cutoff, confirmed by positivity to EMA, have a high-degree probability of duodenal damage. In selected conditions, a duodenal biopsy may be avoided and a confirmed greatly positive anti-TTG result could be the basis to prescribe a gluten-free diet.
免疫球蛋白 A 抗组织转谷氨酰胺酶（TTG）和抗内肌膜抗体（EMA）均为阳性，对乳糜泻（CD）的阳性预测值接近 100%。本研究的目的是评估任何年龄、CD 高患病概率和 TTG 与 EMA 高滴度阳性的患者，是否存在肠道损伤的高概率，且可能不需要进行活检来进行最终诊断。
在意大利的 4 个中心，对 412 例因疑似 CD 且 TTG 和 EMA 均为阳性而接受小肠活检的连续就诊患者进行了回顾性分析。412 例患者年龄在 10 个月至 72 岁之间。2 位病理学家使用 Marsh 改良分类对活检进行独立评估；在结果不一致的情况下，由第 3 位病理学家检查活检。最终的组织学发现诊断由病理学家委员会分配的常见或最高评分表示。
396 例患者（96.1%）的组织学发现符合 CD（改良 Marsh 分类的 2 级和 3a、3b 或 3c）。使用 3 种检测方法（Celikey、抗 TTG 免疫球蛋白 A、EuTTG），TTG 比值≥7 可以识别所有具有显著黏膜损伤（Marsh≥2）的患者，与年龄和性别无关；特异性和阳性预测值均为 100%。TTG 比值>20 对识别存在绒毛萎缩（Marsh 3a、b 或 c）的患者更具有特异性（99.8%）。
抗 TTG 比值≥7 倍，且 EMA 阳性的患者，十二指肠损伤的可能性较高。在特定情况下，可以避免进行十二指肠活检，而高度阳性的 TTG 结果可以作为开始无麸质饮食的依据。
