Elevated serum surfactant protein A and D in pulmonary alveolar microlithiasis.

Pulmonary alveolar microlithiasis (PAM) is a rare disease characterized by widespread localization of calcispherites in the alveolar spaces. The authors report two cases of PAM, with markedly elevated sera concentrations of surfactant protein-A and surfactant protein-D, which showed a tendency to increase as the disease progressed. Therefore, surfactant protein-A and surfactant protein-D may function as serum markers to monitor the disease activity and progression of PAM.