What is GM-CSF and how is it related to primary PAP?
GM-CSF is a cytokine required to stimulate certain lung cells (alveolar macrophages) to destroy (catabolize) surfactant. The ability of GM-CSF to stimulate alveolar macrophages to destroy surfactant results in removal (clearance) of surfactant from the lungs. In fact, GM-CSF is required to stimulate the ability of alveolar macrophages to remove excess surfactant. Antibodies that recognize GM-CSF and are capable of neutralizing its function (neutralizing anti-GM-CSF autoantibodies) effectively eliminate the function of GM-CSF bound by the antibody. This, in turn, prevents GM-CSF from activating surfactant destroying pathways in alveolar macrophages and thus blocks their ability to remove excess surfactant, which then accumulates abnormally.
