Materials and Methods

Subjects

Blood samples and BAL fluids were obtained from 18 healthy volunteers and 10 patients with biopsy-proven sarcoidosis. Informed consent was obtained following a protocol approved by the Human Investigations Committee of the Emory University School of Medicine.
All subjects underwent standardized history and physical examination by one of two authors (G.W.S. or R.L.P.). Spirometry was performed with equipment meeting American Thoracic Society guidelines using the regression equations of Crapo and colleagues to determine the percent of the predicted normal value. Healthy volunteers were accepted for study if they had no respiratory symptoms within one month of the study, normal posteroan-terior radiographs, and pulmonary function within the normal range for age, height, and sex. Chest radiographs of sarcoidosis patients were classified as follows: type 0, no adenopathy or infiltrates; type 1, hilar adenopathy only; type 2, hilar adenopathy with parenchymal infiltrates; type 3, parenchymal infiltrates only.
Blood collection
Blood was collected in citrated Vacutainer tubes (Becton Dickinson, Rutherford, NJ) from an antecubital vein-at the, time of bronchoscopy. The blood was centrifuged at 4()0 g for 10 min at room temperature. The plasma was aspirated using sterile polystyrene pipettes and made platelet-poor by centrifugation at 1,000 g for 30 min (Scientific Products, McCraw Park, 111). Plasma samples were frozen at — 70°C until they were assayed.
Bronchoalveolar Lavage
Bronchoalveolar lavage was performed by fiberoptic bronchoscopy with the patient receiving topical anesthesia. Lavage was performed in a subsegmental bronchus of the right middle lobe regardless of the chest radiographic appearance. One hundred fifty milliliters of sterile saline was instilled and withdrawn by gentle suction in three 50-ml aliquots. Average lavage recovered was 99 ml (median, 99 ml; range, 66 to 120 ml) for healthy volunteers and 81 ml (median, 80 ml; range, 62 to 100 ml) for patients with sarcoidosis. Bronchoalveolar lavage specimens were transported to the laboratory on ice. The specimens were passed through sterile gauze and centrifuged. Cell-free BAL fluids were concentrated 100 times using M inicon В15 concentrator chambers (Amicon, Danvers, Mass). Bronchoalveolar lavage cells were suspended in RPMI 1640 (Me-diatech, Washington, DC) medium containing 10 percent fetal calf serum spun onto microscope slides by centrifugation (Cytospin 2, Shandon, United Kingdom). The cells were stained with Wrights stain and cell differentials were performed by counting and averaging four fields of 100 cells per field.