Human GM-CSF Autoantibodies and Reproduction of Pulmonary Alveolar Proteinosis

To the Editor: Idiopathic pulmonary alveolar proteinosis is a rare disease in which surfactant lipids and proteins accumulate in pulmonary alveolar macrophages and alveoli, resulting in respiratory insufficiency and, in severe cases, respiratory failure.¹ Granulocyte–macrophage colony-stimulating factor (GM-CSF) autoantibodies occur in these patients² and may mediate the pathogenesis of this disease, but they are also present in healthy persons and in immune globulin prepared from plasma obtained from healthy persons. Since GM-CSF is required for surfactant catabolism by alveolar macrophages in mice, we hypothesized that high levels of GM-CSF autoantibodies (i.e., levels sufficient to eliminate endogenous GM-CSF priming of myeloid . . .