[Value of the cytologic and biochemical study of alveolar lavage fluid in the evaluation of the developmental ability of sarcoidosis].

To study indicators of disease activity in sarcoidosis, bronchoalveolar lavage (BAL) and serum angiotensin-converting enzyme (SACE) measurement were performed in 39 patients with active sarcoidosis and in 13 patients with inactive sarcoidosis. All patients were non-smokers. Results were compared to those from 9 non-smoking controls and 20 patients with non-granulomatous interstitial lung disease. Lymphocyte counts, IgG concentrations and the IgG/K ratio were high in BAL fluid specimens from patients with active sarcoidosis, indicating a relationship between cellular and humoral immunity. Conversely, specimens from inactive sarcoidosis patients showed supranormal lymphocyte counts with IgG levels and a IgG/K ratio that did not differ significantly from those in controls or patients with interstitial lung disease (p greater than 0,05). Patients with active sarcoidosis that abated after 6 to 12 months had an initial lymphocytosis of 28.7% and a IgG/K ratio under 170 mg/mmol. We conclude that IgG concentrations and the IgG/K ratio are better discriminators between active and non-active or nearly resolved disease than lymphocyte counts. SACE assay is not sufficiently discriminative.