The role of macrophages in SARS-Cov-2 infection

Lymphopenia appears to be common in patients with severe COVID-19. A preprint by Feng et al. has just been realised on this subject. They studied six patients who died from COVID-19 using immunohistochemistry and immunofluorescence to characterise spleens and lymph nodes. The authors noted splenic and lymph node atrophy and necrosis, but also significant lymphocytic apoptosis. ACE2-expressing CD68⁺CD169⁺ macrophages containing SARS-Cov-2 nucleoprotein antigen were detected. The findings suggest that SARS-CoV-2 migrates into spleens and LNs through macrophages and that macrophages could contribute to viral spread, excessive inflammation and activation-induced lymphocytic cell death during SARS-CoV-2 infection.

Reference: Feng, Z. et al. The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) directly decimates human spleens and lymph nodes. Preprint at medRxiv  https://doi.org/10.1101/2020.03.27.20045427 (2020)