DPP4 and COVID-19: While the clinical association between MERS and thrombosis has not been previously reported, its pathogenesis was studied in mouse models by Li et al in 2016.[20] Histological examination revealed microthrombi in the pulmonary vasculature of transgenic mice expressing human dipeptidyl peptidase 4 (hDPP4), the receptor for MERS entry into human cells.[20] Among our patients, MERS patients suffered from episodes of arterial ischemia more frequently than COVID-19 patients (8.3% vs 6%); however, this difference was not statistically significant.