Bleomycin is potentially capable of inducing a diffuse interstitial fibrosis of 
the lung, the pathogenesis of which has not yet been elucidated. The authors 
have demonstrated that after 48 hr of acute treatment, morphological and 
functional modifications could be seen in type II pneumocytes, which are 
responsible for surfactant production. This might be the earliest stage of 
pulmonary damage.