To determine if the differential expression of MCEMP1 and HLA-DRA were seen in immune cells of the bronchoalveolar lavage fluid (BALF), we analysed 78,666 BALF single cells in 6 severe and 3 mild COVID-19 subjects based on a previously published dataset (GSE145926).45 The gene discussed is MCEMP1; the disease is COVID-19.