A homogeneous population of 73 sarcoidosis patients with recent onset sarcoidosis, no smoking habits, and no previous treatments was serially evaluated in a study of the spontaneous evolution of sarcoidosis. This evaluation comprised clinical, radiographic, biological, and functional assessments as well as assessments of fluids recovered by BAL. We determined the natural history of alveolar lymphocytosis in early stage sarcoidosis and the predictive value of such lymphocytosis for the outcome of the disease. We focused on the outcome at 2 years because it is the usual time of spontaneous recovery; after 2 years the disease enters the chronic phase, and more complications are likely to occur. We found that the initial lymphocytosis observed during the very early stages of the disease had no predictive value for the outcome. Conversely, the persistence of a high alveolar lymphocytosis within the first year of evolution is strongly correlated to a nonrecovery at 2 years, and thus to a chronic phase of sarcoidosis.