IL-12/IL-23 blockade reveals patterns of asynchronous inflammation in pyoderma gangrenosum

Pyoderma Gangrenosum (PG) is a rare and extremely painful neutrophilic dermatosis associated with non-healing cutaneous ulcers affecting 3-10 individuals per million people. The etiology and molecular pathogenetic events of this disease are yet unknown. To investigate how this therapeutic regime shaped the underlying inflammatory response, we performed spatial transcriptomics on lesional biopsies from patients before and after ustekinumab treatment. Our study provides high resolution temporal insights into the inflammatory environment of PG lesional skin following treatment with IL-12/IL-23 blockade in two patients with classic and peristomal PG. This work highlights that while inhibition of representative cytokines of the Th1 and Th17 pathways shows promise as a treatment for PG patients, it does not dampen all active inflammatory pathways. Overall design: Two PG patients with a samples/skin biopsy before and after ustekinumab administration. All samples were used for the spatial transcriptomic analysis.