Air-space immunoglobulin production and levels in bronchoalveolar lavage fluid of normal subjects and patients with sarcoidosis.

The purpose of this study was to examine the relationship between immunoglobulin production and immunoglobulin levels in bronchoalveolar lavage (BAL) fluid and serum of normal subjects and patients with sarcoidosis. Eleven normal volunteers and 17 patients were studied. In normal subjects, no important relationship existed between the number of immunoglobulin-secreting cells and immunoglobulin levels in BAL or serum. By contrast, in patients with sarcoidosis, a highly significant correlation existed between the number of IgG secreting cells and IgG/alb% in BAL (p = 0.008) and between the number of IgG secreting cells in BAL and serum IgG mg/ml (p = 0.002). Similar associations did not exist for IgA and IgM. These data demonstrate for the first time the relationship between immunoglobulin production and immunoglobulin levels in normal persons, and convincingly show that immunoglobulin production at sites of disease activity is responsible for hypergammaglobulinemia in BAL and serum of patients with sarcoidosis.