Autoimmune PAP (aPAP) develops because of circulating autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF), and most affected individuals present to clinical attention in their fourth or fifth decade of life with progressive shortness of breath (SOB) and productive cough [6, 7]. Here, CSF2 is linked to autoimmune pulmonary alveolar proteinosis.