Available online 5 January 2024

Sarcoidosis is a rare granulomatous disease of unknown aetiology belonging to the wide group of interstitial lung diseases.). Although the limitlessness of BAL fluid is debated, it remains one of the best matrices for studying the pathogenesis of sarcoidosis. Natural killer (NK) cells have been described in BAL fluid from sarcoidosis patients. Elevated NK cells in BAL fluid from sarcoidosis patients have been found to be associated with poor outcomes. In this study, NK cells were evaluated in BAL samples from sarcoidosis patients at the time of diagnosis and associated with clinical characteristics in order to evaluate their prognostic role. Of the 276 patients suspected to have sarcoidosis on the basis of clinical and radiological findings, 248 had a final diagnosis of sarcoidosis. Clinical parameters, Scadding stage, and extrapulmonary localization were collected in a database. It resulted in fibrotic sarcoidosis patients being associated with an increase in lymphocyte percentages in BAL samples, particularly NK cells when compared with other groups. From ROC analysis, NK cell percentages in BAL samples resulted as being the best predictive markers in discriminating stage 4 of sarcoidosis from other RX stages (AUC=0.85, p<0.0001). Furthermore, after the stratification of patients on the basis of the number of extrapulmonary localizations, patients with an higher number of extrapulmonary localizations also showed higher percentages of NK cells in BAL fluid. In conclusion, NK cell percentages in BAL fluid can be considered a good prognostic marker of fibrotic phenotypes of sarcoidosis and involvement of other organs, although their diagnostic utility was poor.

Bronchoalveolar lavage

Sarcoidosis

Natural killer cells

bronchoalveolar lavage

interstitial lung diseases

called bronchoalveolar cytology threshold

forced expiratory volume in the first second

diffusing capacity of the lungs for carbon monoxide

The data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the corresponding author upon reasonable request.

© 2023 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L.U.