BRONCHOALVEOLAR LAVAGE IMMUNOGLOBULIN-A AND IMMUNOGLOBULIN-G AND ANTIPROTEASES CORRELATE WITH CHANGES IN-DIFFUSION INDEXES DURING THE NATURAL COURSE OF PULMONARY SARCOIDOSIS

We wanted to determine whether cell populations and soluble components in bronchoalveolar lavage (BAL) could be useful in predicting the out come of lung function and chest radiography in patients with untreated pulmonary sarcoidosis. Analysis of soluble proteins in BAL fluid, inc luded the levels of immunoglobulins and the two major antiproteases, a lpha(2)-macroglobulin (alpha(2)-M) and alpha(1)-protease inhibitor (al pha(1)-PI), expressed as a relative coefficient of excretion (RCE). Th irty one nonsmoking patients with biopsy proven sarcoidosis, who remai ned untreated, had reassessment of lung function tests after 6-54 mont hs (median 21 months). No correlation was observed between initial BAL data and changes in lung volumes and radiographic opacities. By contr ast, the initial BAL immunoglobulin A and G (IgA and IgG) RCE correlat ed inversely with the change in transfer factor for carbon monoxide (T LCO) in the whole group and in patients with sarcoidosis of recent ori gin (estimated disease duration <6 months). In the whole group and in patients with longstanding disease (estimated disease duration >24 mon ths, or radiographic Stage 4), the change in carbon monoxide transfer coefficient (KCO) correlated negatively with the initial alpha(1)-PI R CE and positively with the initial helper to suppressor T-cell (T4/T8) ratio. By contrast, no significant difference in BAL cellular and pro tein data was found between patients with recent and longstanding sarc oidosis. We conclude that: 1) among the BAL cellular and protein param eters investigated, immunoglobulins, antiproteases and T4/T8 ratio are predictive markers for the changes of diffusion indices in patients w ith untreated sarcoidosis; and 2) the duration of disease at the time of the BAL procedure should be taken into account when assessing the p redictive value of BAL parameters