PTPRC and ulcer disease: While we also observed changes in CD56+dim NK cell, CD45+ cell, and mast cell signatures, we focused our subsequent efforts on specifically understanding the role of neutrophils in the ulcer phenotypes with and without SARS-CoV-2 infection since neutrophils have been shown to play an important role in COVID-19 disease pathogenesis, particularly in relation to thromboses and multi-organ damage (19, 40, 41).