RT Journal Article SR Electronic T1 BAL findings in a patient with pulmonary alveolar proteinosis successfully treated with GM-CSF JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 277 OP 280 DO 10.1136/thorax.57.3.277 VO 57 IS 3 A1 O D Schoch A1 U Schanz A1 M Koller A1 K Nakata A1 J F Seymour A1 E W Russi A1 A Boehler YR 2002 UL http://thorax.bmj.com/content/57/3/277.abstract AB Background: Idiopathic pulmonary alveolar proteinosis (PAP) has recently been recognised as a disease of impaired alveolar macrophage function caused by neutralising anti-granulocyte-macrophage colony-stimulating (anti-GM-CSF) autoantibodies. Subcutaneous recombinant human GM-CSF is a novel treatment for PAP, but its mechanism of action is unclear. Methods: Clinical, functional, and bronchoalveolar lavage (BAL) findings were prospectively evaluated in a patient with PAP treated with daily subcutaneous GM-CSF 8 μg/kg for 12 weeks. Results: Treatment resulted in improvements in dyspnoea, lung function, and peak cycle ergometry performance. In serum and BAL fluid the titre of anti-GM-CSF autoantibodies was raised at baseline and markedly reduced on treatment. At baseline the BAL fluid cellular profile showed a decrease in the absolute number and the percentage of macrophages (50%) and an increase in lymphocytes (45%), predominantly CD4+. This cellular distribution remained unchanged after 6 and 12 weeks of treatment while macrophages became morphologically normal and functionally improved. Extracellular proteinaceous material completely disappeared. Conclusions: Clinically successful treatment of PAP with GM-CSF was associated with a profound reduction in GM-CSF neutralising autoantibodies, improvement in alveolar macrophage morphology and function, but persistent BAL lymphocytosis.