SPONTANEOUS INTERLEUKIN-2 RELEASE OF BRONCHOALVEOLAR LAVAGE CELLS IN SARCOIDOSIS IS A CODETERMINATOR OF PROGNOSIS

There is mounting evidence that activated interleukin 2 (IL-2)-releasi ng lymphocytes play a central role in the immunopathogenesis of sarcoi dosis by directing inflammatory reactions and granuloma formation. In the context that a significant proportion of these cells accumulates i n the lung and releases mediators, we hypothesized that different immu nologically defined stages of sarcoidosis can be identified. A cohort of 89 sarcoidosis patients was allocated to four groups according to t he following criteria: stage A, a low number of bronchoalveolar lavage (BAL) lymphocytes (<20%) without IL-2 release (<1 unit/ml in BAL cell culture supernatant); stage B, BAL lymphocytes <20%, with IL-2 releas e (greater than or equal to 1 unit/ml); stage C, BAL lymphocytes great er than or equal to 20% with IL-2 release; and stage D, greater than o r equal to 20% BAL lymphocytes without IL-2 release. Although patients of stages C and D (n = 49) exhibited lymphocytic inflammation, only 2 0/49 of these patients had activated IL-2-releasing alveolar lymphocyt es. BAL of groups A and B showed a low number of lymphocytes, but the lymphocytes were activated in 20/40 patients. Forty-four patients not receiving therapy were reevaluated by pulmonary function tests 8 +/- 1 months after BAL. Progressive disease was found in 9/12 patients of g roup C and stable or regressing disease in 13/13 patients of group A. These results demonstrate that a combination of BAL parameters can yie ld prognostic information.