In other pathological situations, BAL can usefully serve to direct further investigations. Accumulation of BAL T-lymphocytes with prevalence of CD4+ cells is suggestive of sarcoidosis, whilst prevalence of CD8+ cells is suggestive of hypersensitivity pneumonitis [76] . Also, an increase in BAL eosinophils suggests pulmonary infiltrates associated with eosinophilia syndromes [77] . Depending of the underlying diseases, a number of cellular and molecular investigations can be proposed including the studies of various surfactant components, phospholipids and apoproteins [78] .