Pulmonary alveolar proteinosis (PAP) is a rare cause of chronic interstitial lung disease in children characterised by accumulation of a lipoproteinaceous material in the alveoli.

Synopsis

 Bronchoalveolar lavage

• milky appearance of the return fluid
• periodic acid-Schiff staining material in the alveolar macrophages

Etiology

 primary PAP

• SFTPB mutations with SP-B deficiency (early-onset PAP)
• SFTPC mutations with SP-C deficiency (MIM.178620) at 8p21
• CSF2RB mutations (MIM.138981)
• ABCA3 mutations with neonatal surfactant deficiency

 secondary PAP (associated PAP)

• immunodeficiency
  • constitutional immunodeficiency
  • acquired immunodeficiency
    • AIDS and HIV infection
    • bone marrow allograft

• blood disease
  • myeloid leukemia
  • sideroblastic anemia

• pulmonary infections
  • Pneumocystis carinii
  • Nocardia
  • Histoplasma

• lysinuric protein intolerance
• auto-immune anti-GM-CSF antibodies
• dermatomyositis

References

 de Blic J. Pulmonary alveolar proteinosis in children. Paediatr Respir Rev. 2004 Dec;5(4):316-22. PMID: #15531257#

 Trapnell BC, Whitsett JA, Nakata K. Pulmonary alveolar proteinosis. N Engl J Med. 2003 Dec 25;349(26):2527-39. PMID: #14695413#