Ex vivo Drug Metabolism Using Primary Human Hepatocytes for the Detection of Metabolite-Dependent Antibodies to Red Blood Cells.

Background: In general, the detection of the causative drug in patients who develop allergies related to drugs is very complicated or even impossible. To date, urine and serum samples from patients who have received the drug suspected to be associated with adverse drug reactions (ex vivo antigens) have rarely been used to detect metabolite-dependent antibodies (mdab) to red blood cells (RBCs). Here, we investigated whether ex vivo drug metabolism using primary human hepatocytes might be a better alternative for obtaining the metabolites needed for the assays. Methods: Two serum samples containing mdab from 2 patients who had previously developed severe immune hemolytic anemia associated with diclofenac and 5-FU, respectively, were retested in the presence of urinary metabolites from patients and from ex vivo metabolism in primary human hepatocytes seeded in 2D monoculture. Results: Both mdab tested were detectable with urine as a source of drug metabolites, and with ex vivo drug metabolites obtained from the hepatocyte cell culture, using enzyme-treated RBCs. Conclusion: The results obtained in this study are encouraging, not only in terms of improving the detection of mdab to blood cells but also in other forms of allergies related to drugs. Ex vivo drug metabolism using hepatocyte cell culture may represent a standardized and controllable alternative to urine or serum samples for the detection of mdab to any affected human cells.