Mucosal Molecular Pattern of Tissue Transglutaminase and Interferon Gamma in Suspected Seronegative Celiac Disease at Marsh 1 and 0 Stages

Background/Aim: In celiac disease (CD), there is increased mRNA coding for tissue transglutaminase (tTG) and interferon gamma (IFN gamma). In seronegative celiac patients, the mucosal immune complexes anti-tTG IgA/tTG are found. We assayed tTG- and IFN gamma-mRNA in the mucosa of patients with a clinical suspicion of seronegative CD and correlated the values with intraepithelial CD3 lymphocytes (IELs). Materials and Methods: Distal duodenum specimens from 67 patients were retrieved and re-evaluated for immunohistochemically proven CD3 IELs. Five 10 mu m sections were used for the extraction and assay of tTG and IFN gamma coding mRNA levels using reverse transcriptase real-time polymerase chain reaction (RT-PCR). Samples from 15 seropositive CD patients and 15 healthy subjects were used as positive and negative controls. Results were expressed as fold-change. Results: Our series was divided into three groups based on IEL count: >25 (14 patients: group A), 15-25 (26 patients: group B), and 0-15 (27 patients: Group C). tTG-mRNA levels were (mean +/- SD): CD = 9.8 +/- 2.6; group A = 10.04 +/- 4.7; group B = 4.99 +/- 2.3; group C = 2.26 +/- 0.8, controls = 1.04 +/- 0.2 (CD = group A > group B > group C = controls). IFN gamma-mRNA levels were: CD = 13.4 +/- 3.6; group A = 7.28 +/- 3.6; group B = 4.45 +/- 2.9; group C = 2.06 +/- 1.21, controls = 1.04 +/- 0.4. Conclusions: Our results suggest that tTG- and IFN gamma-mRNA levels are increased in both seropositive and potential seronegative patients with CD, showing a strong correlation with the CD3 IEL count at stage Marsh 1. An increase in both molecules is found even when IELs are in the range 15-25 (Marsh 0), suggesting the possibility of a gray zone inhabited by patients which should be closely followed up in gluten-related disorders.