Does maternal autoantibody that transfer to newborn cause disease?

Autoimmune pulmonary alveolar proteinosis (aPAP) is associated with excess amount of granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibody (GMAb) in the lung and blood. We experienced a female case with severe aPAP who could continue her pregnancy under home oxygen therapy and delivered a newborn by caesarean section. Maternal serum GMAb remained high level for up to one year after the delivery, although aPAP entered remission by whole lung lavage. While the newborn oxygen saturation as well as serum Krebs von den Lungen-6 and surfactant protein-D levels had been normal until one year. As GMAb likely transfer to the newborn and might cause the same disease, we carefully monitored both maternal and the newborn serum GMAb levels after the birth for up to one year. We confirmed that GMAb passively transferred to the newborn circulation but rapidly decreased exponentially to the cut-off level. It is suggested that this rapid decrease might prevent the newborn from developing aPAP.