Pulmonary function abnormalities in patients with primary Sjögren's syndrome.

Thirty-two patients with primary Sjögren's syndrome (SS) were studied in order to determine the frequency of pulmonary disease using respiratory function tests. Eleven of the 32 patients revealed positive symptoms compatible with lung disease, including dyspnea, dry or productive cough and pleuritic pain. Seven of these 11 patients also showed a positive physical examination, and 5 showed abnormal chest roentgenograms. Restrictive lung disease was detected in 28.1% of the patients, obstructive disease in 21.8%, and 25% showed a combination of these features (mixed disease). Only 8 patients had completely normal function. There was no significant relationship between respiratory changes and age, smoking habits or glandular and extraglandular manifestations. Positive antinuclear antibodies (p < 0.03) detected by the indirect immunofluorescence test, and anti-SS-A(Ro) and anti-SS-B(La) antibodies (p < 0.009) detected by Ouchterlony occurred more frequently in those patients with primary SS and restrictive pulmonary disease. The patients with anti-SS-A(Ro) and anti-SS-B(La) antibodies also showed significantly lower values for total lung capacity (TLC) (p < 0.0001) and forced vital capacity (FVC) (p < 0.0005) than patients without these serum abnormalities. The study of primary SS may help to elucidate the prevalence of lung abnormalities and their relationship with serum autoantibodies.