Familial lung disease associated with proliferation and desquamation of type II pneumonocytes
P. M. Farrell, E. F. Gilbert, J. J. Zimmerman, T. F. Warner and T. N. Saari
A family is described in which certain infants presented with a diffuse
parenchymal pulmonary disorder characterized by proliferation and
desquamation of alveolar epithelial cells that progressed to severe
pulmonary fibrosis and cystic dysplasia, resulting in "honeycomb" lung
typical of chronic pulmonary interstitial disease (idiopathic pulmonary
fibrosis) at death. Electron microscopic examination of a lung biopsy
specimen from one infant revealed that the proliferating/desquamating cells
were ultrastructurally normal-appearing type II pneumonocytes with
osmiophilic lamellar bodies. This patient did not respond to prednisone
therapy, but she showed great improvement with chloroquine therapy, which
was confirmed by a repeated lung biopsy. Possible mechanisms that might
account for the effect of chloroquine, such as inhibition of DNA synthesis,
as well as the cellular pathobiology of type II pneumonocyte proliferation
in this disease, are discussed.
