Empirically, we found that WLL were the most efficient treatment. This was clearly shown for the short term; during 49 instances investigated until the age of 11, the amount of nasal oxygen flow was reduced in 40 after the lavages ( Figure 3B ). This effect could be sustained for many years demonstrating long term efficacy. However the extreme value of WLL was only very recently Figure 3 Whole lung lavages were performed, due to the small sizes of the airways until the age of 6 y, via a blocked endotracheal tube through which the child was ventilated ( Figure. 3 A, 1.) and through which also a pulmonary artery catheter ( Figure. 3 A, 3., blue) was inserted and blocked in the left or right main stem bronchus (small syringe) and the lavage was done ( Figure. 3 A, 4., large syringe). The tight fit of the blocked pulmonary artery catheter was continuously monitored via a 1.8 mm endoscope ( Figure. 3 A, 2., black). Figure. demonstrated unequivocally following implementation of our concept of very aggressive WLL. Up to the age of 10 years, WLL were done more or less to ameliorate partial respiratory insufficiency, i.e. to decrease the need for additional oxygen. From year 10 onward, we performed one lavage per month, in order to try to completely clear the lung from its proteinosis load. This approach was very successful and resulted in complete resolution of partial respiratory insufficiency for the first time. The patient started puberty, growth and weight were sustained by oral nutrition without need of using the percutaneous tube and the dependency on supplemental oxygen up to that point in time, could be finished. This also led to increased self-confidence and better integration at school. Also, the lung function improved very rapidly and chest radiograph cleared to almost normal ( Figure 1D , E; Figure  3C ). Together somato-psychosocial condition substantially improved. A consecutive brief trial to increase the time lag between the lavages failed and an interval of about 4 weeks was maintained.