Characteristics of Tissue Donors
The characteristics of the subjects with fatal COVID-19 are described in Table 1. Postmortem lung autopsy samples were collected at Lviv Regional Pathological Anatomy Office, CU ENT «Pulmonology Lviv Regional Diagnostic Center» from patients who were COVID-19 positive by RT-PCR and presented with bilateral pneumonia during admission into the hospital (Table 1) . The mean age of the subjects was 60.4 years with a range of 30 to 80 years (4 female and 4 male patients). Patients were admitted into the hospital on average 7.1 days from the onset of symptoms and 7 of 8 subjects were in the hospital for more than 10 days (range 10 to 21 days). One patient died on 5th day after hospitalization. The biochemical analyses revealed a high percentage of blood neutrophils (non-COVID-19 patients 57.5 % vs COVID-19 patients 79.8 %; P value <0.03) and decreased lymphocytes (non-COVID-19 patients 36 % vs COVID-19 patients 14.9 %, Pvalue <0.09). Erythrocyte sedimentation rate (ESR), a plasma marker for inflammatory response, was elevated in COVID-19 patients compared to non-COVID-19 patients (51.7±10.7 vs 17±9.8; P value <0.0004). Six lung autopsy samples collected from patients who died of non-COVID-19 related diseases were also analyzed.