SANDWICH ELISA FOR GLUTATHIONE-S-TRANSFERASE ALPHA1-1 - PLASMA-CONCENTRATIONS IN CONTROLS AND IN PATIENTS WITH GASTROINTESTINAL DISORDERS

Class Alpha glutathione S-transferases (GST-Alpha) are found in high c oncentrations in human liver. Increased plasma concentrations of GSTA1 -1, the most abundant isoform of GST-Alpha, are a very sensitive marke r for hepatocellular leakage. A sandwich-type ELISA was developed, bas ed on a monoclonal antibody specific for human GSTA1-1 and a polyclona l rabbit anti-human GST-Alpha antiserum. The assay is specific for hum an GSTA1-1, and has a detection limit of 0.04 mu g/L. The distribution of plasma GSTA1-1 concentrations in 350 blood donors was nearly norma lized by logarithmic transformation and an upper normal reference conc entration of 5.9 mu g/L was calculated. Men had significantly higher p lasma GSTA1-1 concentrations than women (P <0.0001). In women, but not in men, a significant increase was noted with age (P <0.05). In patie nts with inflammatory bowel disease (n = 210), gastrointestinal tumors (n = 70), irritable bowel disease (n = 36), or chronic pancreatitis ( n = 12), plasma GSTA1-1 concentrations were similar to those of contro ls. In contrast, plasma GSTA1-1 concentrations were increased to a sim ilar extent as alanine aminotransferase activities in patients with li ver disorders (n = 37).