[The role of chemotactic factors in the pathogenesis of sarcoid granuloma formation].

There is evidence suggesting that macrophages and epithelioid cells, predominant cells in sarcoid granuloma, are derived from circulating monocytes on a gradient of chemotactic factors between the lesion and the circulation. A previous study by the author showed that epithelioid cells and lymphocytes from sarcoid granulomas released chemotactic factors to attract blood-derived mononuclear cells. The present study was undertaken to further explore the role of chemotactic factors in the pathogenesis of sarcoid granuloma formation. Twenty two sarcoid patients, 14 patients with active pulmonary involvement and 8 patients without pulmonary involvement, were lavaged and the bronchoalveolar lavage (BAL) fluids were evaluated for chemotactic activity. Chemotactic activity was detected in BAL fluid from sarcoid patients with active pulmonary disease, but not from those without pulmonary involvement. Chemotactic activity for mononuclear cells in the BAL fluid correlated with the percentage of lymphocyte numbers (r = 0.702, p less than 0.05) and number of CD4+ lymphocytes (r = 0.796 p less than 0.02) present in the BAL fluids, which has been proved to reflect disease activity. Chemotactic activity was independent of the amounts of albumin in BAI fluid (r = 0.271, p less than 0.10). Chemotactic factors in BAL fluid were eluted in 4 different regions on molecular sieving and were stable at 56 degrees C for 30 min. However, chemotactic activities were abolished completely by treatment at 100 degrees C for 30 min or trypsinization. Our observations suggest that chemotactic activity in BAL fluid from sarcoid patients reflects the disease activity contributing to formation of sarcoid granulomas.