Air-Space Immunoglobulin Production and Levels in Bronchoalveolar Lavage Fluid of Normal Subjects and Patients with Sarcoidosis^1–4

Abstract

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.

Bronchoalveolar lavage immunoglobulin A and G and antiproteases correlate with changes in diffusion indices during the natural course of pulmonary sarcoidosis

“…High IgG/albumin ratio and increased numbers of IgG secreting cells has been documented in BAL fluid from sarcoidosis patients, suggesting that immunoglobulins are produced locally [21,[31][32][33][34]. VALEYRE et al [29] found a negative correlation between BAL IgG/ albumin but not IgA/albumin ratio and TLCO corrected for alveolar volume in patients with sarcoidosis of recent origin (radiographic Stages 1, 2 and 3, mean disease duration of 12.5 months).…”

“…This indicates that immune process could be predominantly associated with TLCO impairment in early stages of the disease. However, it remains unclear whether BAL immunoglobulins represent only markers of immunological events or play a direct role in the pathogenesis of alveolocapillary derangement [31][32][33]. Circulating immune complexes have been described in acute sarcoidosis [1], and it has recently been suggested that immunoglobulins, in particular IgA and IgG, could directly interact with alveolar macrophages [36].…”

Immunoglobulins in the lung.

“…The first is an increase in the transudation of protein from the blood, presumably because of inflammation within the lung. This conclusion is based on the observation that albumin concentrations in lavage fluid are also frequently increased in sarcoidosis, "1 12 37 The increased immunoglobulin concentrations in lung secretions from patients with interstitial lung disease clearly result mainly from local synthesis by plasma cells and, by contrast with the normal lung, a considerable proportion of this protein is derived from cells lining the airways. The source of these cells is not known.…”

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“…In normal subjects and in patients with various lung diseases, some local immunoglobulin production has been demonstrated in the lung. This is probably derived from plasma cells contained in the bronchial lamina propria or from cells in the airway lumens [31].…”