Calgranulin B (S100A9) Levels in Bronchoalveolar Lavage Fluid of Patients with Interstitial Lung Diseases

Calgranulins are small calcium-binding proteins with several immunological functions involved in inflammatory processes. Calgranulin A is reported to be mainly associated with acute inflammation while calgranulin B seems to play a role in chronic inflammatory disorders. In this study we used a proteomic approach to analyse calgranulin B expression in bronchoalveolar lavage (BAL) from a group of patients with different interstitial lung diseases. Two dimensional electrophoresis analysis of BAL was performed in 11 idiopathic pulmonary fibrosis patients, nine sarcoidosis patients, 11 with systemic sclerosis patients and five healthy controls. Significantly higher (p<0.001) calgranulin B percentage volumes were observed in BAL from IPF patients than controls and other ILD patients. This result sustains the hypothesis that calgranulin B could be involved in chronic lung diseases, probably through increased expression and enhanced activation of alveolar polymorphonuclear cells related to idiopathic pulmonary fibrosis. Quantitative analysis by an easier method applied to a larger population will be necessary to determine whether calgranulin B could be a good marker of disease severity.