Temporary remission of autoimmune pulmonary alveolar proteinosis after infectious episodes

Pulmonary alveolar proteinosis (PAP) is a rare disease of unknown aetiology. Although resolution occurs in about 30% of autoimmune PAP (APAP) cases, its pathogenesis is not yet sufficiently understood. Two APAP cases at our institute showed remission following infectious episodes. Case 1: a 40-year-old female APAP patient suffered from herpes encephalitis and was treated with an antiviral drug. Her symptoms and radiological results resolved within two months of her recovery from the encephalitis. Case 2: A 53-year-old male current-smoker APAP patient was admitted for pneumonia. After treatment with antibiotics, his radiological results and symptoms improved. He experienced a similar resolution of APAP after another infectious episode two years later. Remission of APAP may occur following viral or bacterial infection. We hypothesise that remission of APAP is triggered by the induction of granulocyte-macrophage colony-stimulating factor (GM-CSF) following viral or bacterial infection. Further studies of APAP remission, and especially of the effects of GM-CSF induction, are needed. (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 85-90).