Whole lung lavage (WLL) is currently the standard therapy for pulmonary alveolar proteinosis (PAP). Nevertheless, some PAP patients respond poorly to WLL or require it frequently. The present paper reports a patient with autoimmune PAP with persistent disease despite three WLL treatments over 10 months. Plasmapheresis with ten 1.5-L plasma exchanges was performed, which lowered the serum granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibody level from 250 microg mL(-1) to 156 microg mL(-1) but did not improve respiratory impairment. Further WLL therapy was required and transiently effective. Serum GM-CSF autoantibody levels declined progressively, reaching a value of 56 microg mL(-1) 80 weeks after completion of plasmapheresis. However, this decrease was not accompanied by clinical improvement and the patient required additional WLL therapy. The results confirm that minor reductions in serum granulocyte-macrophage colony-stimulating factor autoantibody levels from plasmapheresis are not reflected in clinical improvement in the severity of lung disease in pulmonary alveolar proteinosis.