We have previously reported that alveolitis correlates with clinical, roentgenologic, and functional parameters of pulmonary involvement in primary Sjögren's syndrome (1SS). In the present study, we analyzed the liquid phase characteristics of bronchoalveolar lavage (BAL) in the same 19 patients with 1SS. Our results show that patients with "high alveolitis" (group A, BAL lymphocytes > 15.2 percent) have increased values of total protein, albumin, IgA, and IgG and in their BAL fluid compared with patients with "low alveolitis" (group B) and control subjects. Also interleukin 2 (IL-2) was detected in more "high alveolitis" patients while IgM, IL-2R, and interferon gamma (IFN-gamma) were detected only in this group. There were no differences between the two groups in serum values of all above factors as well as in the presence of rheumatoid factor, extractable nuclear antibodies, and antinuclear antibodies. The increased values of immunoglobulins and cytokines in the BAL fluid of patients with intense alveolitis, in the absence of serum differences, speak for their local production and suggest activation of local immune mechanism.