It is conceivable that preoccupation with the granular pneumocyte's role in the reactions to alveolar injury is premature; perhaps it is even irrelevant. However, there is sufficient evidence to justify at least some additional probing into the possibility that this cell has an important reparative function unrelated to surfactant synthesis. A better understanding of this function may also contribute to clarification of the relationships between organizing interstitial pneumonia and such reactions as desquamative interstitial pneumonia and pulmonary alveolar proteinosis in which the granular pneumocyte is especially prominent.
Charles B. Carrington, Thomas J. Green. Granular Pneumocytes in Early Repair of Diffuse Alveolar Injury. Arch Intern Med. 1970;126(3):464–465. doi:10.1001/archinte.1970.00310090094009