1C11 monoclonal antibody detects SI-CLP in bronchoalveolar lavage samples and peripheral-blood leukocytes. Western blot analysis was performed using 1C11 mAb. (A) Different pattern of SI-CLP expression was observed in cells isolated out of bronchoalveolar lavage (BAL). BAL 01, 02, 04, and 05 are obtained from patients with chronic bronchitis; BAL 03 was obtained from patient with sarcoidosis, undergoing corticoid therapy. (B-C) PBLs were isolated from fresh blood samples by gradient centrifugation. PBL samples 01 to 05 correspond to BAL samples 01 to 05; PBL samples 06 to 14 are obtained from healthy donors. PBL samples 06 and 11 are obtained from the same healthy donor.