Evaluation of serum carbohydrate-deficient transferrin by HPLC and MALDI-TOF MS

The percentage of carbohydrate-deficient transferrin (%CDT) in serum is a marker of habitual alcohol intake that can be determined by antibody detection of abnormal disialo sugar chains at D432 and D630. However, this approach lacks specificity for alcoholic liver disease. To decrease the false-positive rate in patients with non-alcoholic liver diseases, we developed a screening method using the disialo sugar chain at D630 alone. Serum was obtained from 12 patients with alcoholic liver disease, 12 with type C chronic liver disease, 6 with non-alcoholic steatohepatitis (NASH), and 12 healthy non-alcohol drinkers. Transferrin with two sialic acids (disialotransferrin) was fractionated from serum using HPLC, digested with trypsin, and evaluated using MALDI-TOF MS. An abnormal sugar chain at D630 of transferrin was not detected in healthy subjects or in patients with chronic liver disease or NASH, but was detected in 9 patients (75%) with alcoholic liver disease. Positive results were found in 3 samples that were negative using an N-Latex CDT kit and in one sample negative for γ-glutamylaminotransferase and CDT. Detection of CDT by HPLC/MALDI-TOF MS based on an abnormal sugar chain at D630 may permit identification of habitual alcohol drinkers when used in combination with current markers.