Successful haematopoietic stem cell transplantation in a case of pulmonary alveolar proteinosis due to GM-CSF receptor deficiency

Cyril Schweitzer (CS) : A 1.5-year-old girl was referred to the Paediatric Pneumology Department of the University Hospital of Nancy, France, for progressive tachypnoea and hypoxia. She suffered from intrauterine growth retardation, and was born prematurely at 31 weeks’ gestation; birth weight: 1.160 kg (≤2 SD); birth length: 37 cm (≤2 SD). The patient presented with acute respiratory distress syndrome at birth, requiring treatment with a dose of surfactant, 9 days of mechanical ventilation and 8 weeks of oxygen therapy. On arrival to our centre, she was dyspnoeic on exertion and oxygen saturations were between 91% and 94%. Further investigations included a high-resolution CT scan and a bronchoalveolar lavage (BAL). Laureline Berteloot (LB) and Julie Bruneau (JB) : CT imaging of the chest revealed a ‘crazy paving’ pattern whereas analysis of BAL fluid failed to identify any underlying disease. CS : Hypoxia transiently improved after initiation of inhaled corticosteroids and antireflux therapy but relapsed after a few months, so that a second BAL was performed. JB : The second BAL fluid revealed the presence of extracellular lipid and protein deposits and foamy alveolar macrophages. CS and Cecile Bonnet (CeB) : These abnormalities led to a diagnosis of pulmonary alveolar proteinosis (PAP) at the age of 2.6 years, which was confirmed by genetic testing; complex chromosome abnormalities were detected, with (1) deletion of CSF2RA and CRLF2 on the X chromosome inherited from the mother, and (2) a de novo rearrangement of the paternal X chromosome, resulting in loss of both CSF2RA alleles.1 CS, Christophe Delacourt (CD) and Jacques De Blic (JDB) : Recessive mutations in the α or β subunits of the granulocyte macrophage colony-stimulating factor receptor (GM-CSF-R, encoded respectively by CSF2RA and CSF2RB ) cause two subtypes of hereditary PAP.2 Impairment of GM-CSF-dependent surfactant clearance by alveolar macrophages leads to the progressive accumulation of surfactant in the alveolar space …