The Role of in Vitro Detection of Drug-Specific Mediator-Releasing Cells to Diagnose Different Phenotypes of Severe Cutaneous Adverse Reactions.

Propose: The purpose of this study was to investigate panels of enzyme-linked immunospot assays (ELISpot) to detect drug-specific mediator releasing cells for confirming culprit drugs in severe cutaneous adverse reactions (SCARs). Methods: Frequencies of drug-induced interleukin-22 (IL-22)-, interferon-gamma (IFN-gamma)-, and granzyme-B (GrB)-releasing cells were measured by incubating peripheral blood mononuclear cells (PBMCs) from SCAR patients with the culprit drugs. Potential immunoadjuvants were supplemented to enhance drug-induced mediator responses. Results: Twenty-seven patients, including 9 acute generalized exanthematous pustulosis (AGEP), 10 drug reactions with eosinophilia and systemic symptoms, and 8 Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) were recruited. The average frequencies of drug-induced IL-22-, IFN-gamma-, and GrB-releasing cells were 35.5 +/- 16.3, 33.0 +/- 7.1, and 164.8 +/- 43.1 cells/million PBMCs, respectively. The sensitivity of combined IFN-gamma/IL-22/GrB ELISpot was higher than that of IFN-gamma ELISpot alone for culprit drug detection in all SCAR subjects (77.8% vs 51.9%, P < 0.01). The measurement of drug-induced IL -22-and IFN-gamma releasing cells confirmed the culprit drugs in 77.8% of AGEP. The measurement of drug induced IFN-gamma- and GrB-releasing cells confirmed the culprit drugs in 62.5% of SJS/TEN. Alpha-galactosylceramide supplementation significantly increased the frequencies of drug induced IFN-gamma releasing cells. Conclusion: The measurement of drug-induced IFN-gamma-releasing cells is the key for identifying culprit drugs. The additional measurement of drug-induced IL-22-releasing cells enhances ELISpot sensitivity to identify drug-induced AGEP, while the measurement of drug-induced GrB-releasing cells could have a role in SJS/TEN. ELISpot sensitivity might be improved by supplementary alpha-galactosylceramide.