After centrifugation (14 500 g for 5 min) at 4°C the pellet

was resuspended in 500 µl extraction buffer containing 1 M NaCl, incubated on ice for 20 min and centrifuged (14 500 g for 5 min) at 4°C. The supernatant representing the nuclear protein fraction was collected and stored at −70°C until used. To characterize the NFR further, sera of the 11 patients in group 1 subjected to molecular study were analysed for IgA reactivity with nitrocellulose-blotted Caco2 cell proteins. Total cell protein extract, as well as its cytosolic and nuclear fractions, were boiled for 3 min and submitted to denaturing 10% preparative sodium dodecyl sulphate-polyacrylamide gel electrophoresis mTOR inhibitor (SDS-PAGE). Gel-separated proteins were blotted onto nitrocellulose membranes (Protran nitrocellulose transfer membrane; Schleicher & Schuell Whatman VX-809 clinical trial group, Dassel, Germany). Nitrocellulose strips (width 2 cm) were cut from the membranes and were then blocked twice for 5 min and once for 30 min in buffer A [50 mM sodium phosphate buffer at pH 7·4, containing 0·5% Tween 20 and 0·5% bovine serum albumin (BSA)]. Blocked strips were probed overnight at 4°C with sera diluted 1:500 in the same buffer. Thereafter, strips were washed twice for 5 min and once for 15 min with buffer B (50 mM sodium phosphate buffer at pH 7·4, containing 0·5% Tween 20) and incubated overnight at room temperature with a peroxidase-conjugated anti-human IgA polyclonal antibody (Chemicon, Temecula, CA, USA)

diluted 1:8000 in buffer A. Strips were finally washed and dried before exposition to Hyperfilms ECL (Amersham

Pharmacia Biotech, Uppsala, Sweden) for approximately 3–5 s. The purity of nuclear and cytosolic protein fractions triclocarban was assessed by exposing the nitrocellulose-blotted total cell protein extract and its fractions to anti-human histone H2B anti-serum (Chemicon). Significant statistical differences between EMA and NFR antibodies, detected as total IgA, IgA1 and IgA2 in sera of the 11 patients in group 1 subjected to NFR characterization, were calculated by χ2 test for qualitative and independent data. The P-values ≤0·05 were considered significant. At baseline, all 20 untreated CD patients in group 1 showed serum IgA EMA-positive and NFR-negative results. Serum EMA disappeared after 76 ± 34 days from starting the GFD while, at the same time, serum NFR antibodies became apparent. The NFR antibodies cleared completely from sera in the following 75 ± 41 days for a total of 151 ± 37 days from starting the GFD (Fig. 2). At the time of monitoring, 24 of 87 treated CD patients in group 2 showed serum IgA EMA-negative and NFR-positive results, while the remaining 63 patients displayed negative results for both circulating antibodies. The combination of three GFD control levels (self-reported, dietetic assessment and serum EMA determination) highlighted that, during the previous months, the 24 patients presenting serum NFR-positive results were introducing small amounts of gluten.