Objective:To evaluate the diagnostic efficacy of serum anti-deamidated gliadin peptide antibody immunoglobulin A (DGP-IgA) in adult celiac disease.Methods:A retrospective case-control study was conducted. Clinical data of 80 adult celiac disease patients (celiac disease group) treated in the Department of Gastroenterology of the People's Hospital of Xinjiang Uygur Autonomous Region from September 2020 to December 2023 were collected. Meanwhile, 40 healthy individuals who underwent physical examinations were selected as the healthy control group. According to the Oslo definition of celiac disease, 80 celiac disease patients were classified into classical type (52 patients), non-classical type (21 patients), and subclinical type (7 patients). Serum DGP-IgA and anti-tissue transglutaminase antibody immunoglobulin A (tTG-IgA) were measured in both celiac disease and healthy control groups by using the ELISA method. The degree of intestinal mucosal damage in celiac disease patients was assessed by the Marsh Oberhuber histopathological grading system (Marsh grading for short) using the small intestinal biopsy pathological results. Statistical analysis was performed to compare the differences in serum DGP-IgA and tTG-IgA between the two groups, as well as the differences in antibodies among different clinical phenotypes. Spearman's rank correlation analysis was used to evaluate the correlation between serum DGP-IgA level and Marsh grading. Receiver operating characteristic (ROC) curves were plotted to analyze the diagnostic efficacy of DGP-IgA, tTG-IgA, and the combination of DGP-IgA and tTG-IgA for celiac disease.Results:Among the 80 celiac disease patients, there were 19 males and 61 females, with a mean age of 45.31 ± 14.96 years. In the healthy control group, there were 15 males and 25 females, with a mean age of 47.03 ± 11.86 years. There were no statistically significant differences in age and gender between the two groups (both P > 0.05). The level of DGP-IgA and tTG-IgA in the celiac disease group were significantly higher than those in the healthy control group [DGP-IgA: 308.31 (279.86, 349.92) U/ml vs. 269.85 (251.42, 290.40) U/ml, P < 0.01; tTG-IgA: 261.05 (79.23, 2 542.30) U/ml vs. 1.90 (1.90, 2.40) U/ml, P < 0.01]. Further subtype analysis revealed that DGP-IgA level in classical celiac disease patients was higher than that in subclinical celiac disease patients [314.63 (289.35, 357.30) U/ml vs. 275.65 (260.90, 296.72) U/ml, P < 0.05], with statistically significant difference. Serum DGP-IgA level in celiac disease patients was positively correlated with Marsh grading ( r = 0.343, P < 0.01). The ROC curve results showed that the area under curve (AUC) for serum DGP-IgA in diagnosing celiac disease was 0.768, with an optimal cutoff value of 292.51 U/ml, sensitivity of 66.3%, and specificity of 77.5%; AUC for serum tTG-IgA was 0.974, with an optimal cutoff value of 20.1 U/ml, sensitivity of 92.5%, and specificity of 95.0%; AUC for the combination of DGP-IgA and tTG-IgA was 0.991, with a sensitivity of 98.8% and specificity of 97.5%. Conclusions:Serum DGP-IgA alone has limited clinical significance in diagnosing adult celiac disease. The diagnostic efficacy can be improved only when combined with tTG-IgA detection.

Objective:To evaluate the diagnostic efficacy of serum anti-deamidated gliadin peptide antibody immunoglobulin A (DGP-IgA) in adult celiac disease.Methods:A retrospective case-control study was conducted. Clinical data of 80 adult celiac disease patients (celiac disease group) treated in the Department of Gastroenterology of the People's Hospital of Xinjiang Uygur Autonomous Region from September 2020 to December 2023 were collected. Meanwhile, 40 healthy individuals who underwent physical examinations were selected as the healthy control group. According to the Oslo definition of celiac disease, 80 celiac disease patients were classified into classical type (52 patients), non-classical type (21 patients), and subclinical type (7 patients). Serum DGP-IgA and anti-tissue transglutaminase antibody immunoglobulin A (tTG-IgA) were measured in both celiac disease and healthy control groups by using the ELISA method. The degree of intestinal mucosal damage in celiac disease patients was assessed by the Marsh Oberhuber histopathological grading system (Marsh grading for short) using the small intestinal biopsy pathological results. Statistical analysis was performed to compare the differences in serum DGP-IgA and tTG-IgA between the two groups, as well as the differences in antibodies among different clinical phenotypes. Spearman's rank correlation analysis was used to evaluate the correlation between serum DGP-IgA level and Marsh grading. Receiver operating characteristic (ROC) curves were plotted to analyze the diagnostic efficacy of DGP-IgA, tTG-IgA, and the combination of DGP-IgA and tTG-IgA for celiac disease.Results:Among the 80 celiac disease patients, there were 19 males and 61 females, with a mean age of 45.31 ± 14.96 years. In the healthy control group, there were 15 males and 25 females, with a mean age of 47.03 ± 11.86 years. There were no statistically significant differences in age and gender between the two groups (both P > 0.05). The level of DGP-IgA and tTG-IgA in the celiac disease group were significantly higher than those in the healthy control group [DGP-IgA: 308.31 (279.86, 349.92) U/ml vs. 269.85 (251.42, 290.40) U/ml, P < 0.01; tTG-IgA: 261.05 (79.23, 2 542.30) U/ml vs. 1.90 (1.90, 2.40) U/ml, P < 0.01]. Further subtype analysis revealed that DGP-IgA level in classical celiac disease patients was higher than that in subclinical celiac disease patients [314.63 (289.35, 357.30) U/ml vs. 275.65 (260.90, 296.72) U/ml, P < 0.05], with statistically significant difference. Serum DGP-IgA level in celiac disease patients was positively correlated with Marsh grading ( r = 0.343, P < 0.01). The ROC curve results showed that the area under curve (AUC) for serum DGP-IgA in diagnosing celiac disease was 0.768, with an optimal cutoff value of 292.51 U/ml, sensitivity of 66.3%, and specificity of 77.5%; AUC for serum tTG-IgA was 0.974, with an optimal cutoff value of 20.1 U/ml, sensitivity of 92.5%, and specificity of 95.0%; AUC for the combination of DGP-IgA and tTG-IgA was 0.991, with a sensitivity of 98.8% and specificity of 97.5%. Conclusions:Serum DGP-IgA alone has limited clinical significance in diagnosing adult celiac disease. The diagnostic efficacy can be improved only when combined with tTG-IgA detection.