CSF2 and pulmonary alveolar proteinosis: In addition to their clear role in COVID-19, ACA are known to be associated with several lung diseases, such as disseminated atypical mycobacterial infections (AMI; associated with anti–IFN-γ; ref. 7) and pulmonary alveolar proteinosis (PAP; associated with anti–GM-CSF; ref. 8).