Blister fluid as a cellular input for ex vivo diagnostics in drug-induced severe cutaneous adverse reactions improves sensitivity and explores immunopathogenesis
Authors:
- Awad, Andrew
- Mouhtouris, Effie
- Nguyen-Robertson, Catriona Vi
- Holmes, Natasha
- Chua, Kyra Y.L.
- Copaescu, Ana
- James, Fiona
- Goh, Michelle S.
- Aung, Ar Kar.
- Godfrey, Dale I.
- Philips, Elizabeth J.
- Gibson, Andrew
- Almeida, Catarina F.
- Trubiano, Jason A.
Details:
Journal of Allergy and Clinical Immunology: Global, Volume 1, Issue 1, 2022-02-28
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Background Drug-induced severe cutaneous adverse reactions (SCARs) are presumed T-cell–mediated hypersensitivities associated with significant morbidity and mortality. Traditional in vivo testing methods, such as patch or intradermal testing, are limited by a lack of standardization and poor sensitivity. Modern approaches to testing include measurement of IFN-γ release from patient PBMCs stimulated with the suspected causative drug. Objective We sought to improve ex vivo diagnostics for drug-induced SCARs by comparing enzyme-linked immunospot (ELISpot) sensitivities and flow cytometry–based intracellular cytokine staining and determination of the cellular composition of separate samples (PBMCs or blister fluid cells [BFCs]) from the same donor. Methods ELISpot and flow cytometry analyses of IFN-γ release were performed on donor-matched PBMC and BFC samples from 4 patients with SCARs with distinct drug hypersensitivity. Results Immune responses to suspected drugs were detected in both the PBMC and BFC samples of 2 donors (donor patient 1 in response to ceftriaxone and case patient 4 in response to oxypurinol), with BFCs eliciting stronger responses. For the other 2 donors, only BFC samples showed a response to meloxicam (case patient 2) or sulfamethoxazole and its 4-nitro metabolite (case patient 3). Consistently, flow cytometry revealed a greater proportion of IFN-γ–secreting cells in the BFCs than in the PBMCs. The BFCs from case patient 3 were also enriched for memory, activation, and/or tissue recruitment markers over the PBMCs. Conclusion Analysis of BFC samples for drug hypersensitivity diagnostics offers a higher sensitivity for detecting positive responses than does analysis of PBMC samples. This is consistent with recruitment (and enrichment) of cytokine-secreting cells with a memory/activated phenotype into blisters.