IgG autoantibodies against tissue transglutaminase in relation to antinuclear antibodies.

exposure over the previous hours (15) were collected and stored at Ϫ20 °C until analysis (14). Creatinine was assessed in urine according to a kinetic method adapted from the Jaffe method (16). Urinary cotinine results, calculated taking into account the fivefold urine concentration , were expressed with reference to creatinine values. Results were compared using the Student t-test. Urinary cotinine values in children exposed to ETS (14.1 Ϯ 11.9 mg/mol of creatinine) were significantly higher (P Ͻ0.001) than those in nonexposed children (5.1 Ϯ 5.4 mg/mol of creatinine). The proposed cotinine EIA thus enables nonsmokers exposed to ETS to be differentiated from those not exposed. The technique is simple, rapid, can be used in any laboratory having an automated analyzer (open system), and can be applied to large-scale studies. This method can be recommended in epidemiological studies as a control for smoking, an important confounding factor often poorly described in self-administered questionnaires (17). This study is part of the French multicentric study VESTA (Five Epidemiological Studies on Transport and Asthma) coordinated by Dr. D. Zmirou and supported by a grant from the French Ministry of Environment. We are grateful to Prof. P. Beaune for advice. Expired air carbon monoxide and serum thiocyanate as objective measures of cigarette exposure. A rapid gas-liquid chromatographic method for the determination of cotinine and nicotine in biological fluids. Rapid method for the simultaneous measurement of nicotine and cotinine in urine and serum by gas chromatography– mass spectrometry. Automated reaction-rate method for determination of serum creatinine with the Centrifichem. The enzyme transglutaminase (tTg; EC 2.3.2.13) catalyzes, among others, the formation of ⑀-(␥-glutamyl)-lysine bonds between substrate proteins, leading to cross-linked protein polymers (1). The enzyme is synthesized by a broad spectrum of cell types and is widely distributed in human organs (2). Induction and activation of tTG is part of the apoptotic cascade and plays an effector role in this process (3, 4). The enzyme is present in preapoptotic cells and enables the production of a highly cross-linked protein scaffold in apoptotic cells, joining cytoplasmic and membrane proteins and thus maintaining cellular integrity during the formation of apoptotic bodies. This cross-linking of proteins stabilizes the apoptotic bodies and limits the leakage of intracellular components into the extracellular space (1, 5). Recently, tissue tTg has been shown to be the key autoantigen of the so-called anti-endomysium antibodies (IgA type), which are diagnostic for celiac disease (6). IgG antibodies …