IL6 and pneumonia: We found very high expression of both IL-1β and IL-6 by senescent AT2 cells in the lungs of COVID-19 patients, while in the non-COVID-19 control cases, including samples from patients with acute pneumonia, expression was very low in the few senescent AT2 cells detected in lung tissue with fibrosis, atelectasis and inflammatory infiltrates (p<0.0001) (figure 4a–c, supplementary table S1).