Time to reconsider the clinical value of immunoglobulin G4 to foods?

• Published in: Clinical chemistry and laboratory medicine Vol. 46; no. 5; pp. 687 - 690
• Main Authors: Bernardi, Daniela, Borghesan, Franco, Faggian, Diego, Bianchi, Fulvia Chieco, Favero, Elisabetta, Billeri, Lucia, Plebani, Mario
• Format: Journal Article
• Language: English
• Published: Berlin Walter de Gruyter 01.01.2008; New York, NY
• Subjects: Adolescent; Adult; Aged; Biological and medical sciences; Biomarkers - blood; Child; diagnostic accuracy; exclusion diet; False Positive Reactions; Female; Food Hypersensitivity - blood; Food Hypersensitivity - diagnosis; Food Hypersensitivity - immunology; food intolerance; food-specific IgG4 antibody; General aspects; Humans; Immunoassay - methods; Immunoglobulin G - blood; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; Reference Standards; ROC Curve; Sensitivity and Specificity; diagnostic accuracy; Food intolerance; Nutrition; Antibody; IgG4; Feeding; Medicine; Accuracy; Diet; Clinical biology; exclusion diet; Digestive diseases; Intestinal disease; Diagnosis; Food; food-specific lgG4 antibody
• ISSN: 1434-6621; 1437-4331
• DOI: 10.1515/CCLM.2008.131

Background: The usefulness of serum antibodies to common food antigens (immunoglobulin G4; IgG4) assay in management of patients suffering from food intolerance was assessed. Methods: A total of 22 asymptomatic healthy subjects and 68 patients with symptoms referred for suspected food intolerance were studied. Serum IgG4 to 19 common foods was measured by an automated immunoassay. Results: The area under the receiver operating characteristic curve was 0.92 (standard error 0.04) and, at a threshold value of 2.3 U/mL, the IgG4 determination had a sensitivity of 0.81, with a specificity of 0.87. With a pre-test probability of 5% and 20%, the post-test probability of having disease was found to be 24% and 61%, respectively, and 1.1% and 5% if the result was negative. Cohen's κ value (0.83) indicated a good agreement between symptoms and IgG4 concentrations. Conclusion: Serum IgG4 assay may play a role in ruling out food intolerance, because of its satisfactory negative predictive value (0.99). Clin Chem Lab Med 2008;46:687–90.