macrophages COVID lungs (IMAGE) University of California - San Diego Caption Unusually high numbers of macrophages (in brown) were detected in cross-sections of lungs from COVID-19 patients using immunohistochemical techniques. Blue counterstain detects nuclei of all cells in the cross-section. Credit UC San Diego Health Sciences Usage Restrictions Use photo credit License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.