Am. J. Respir. Crit. Care Med., Vol 151, No. 2, 02 1995, 544-547.
Soluble CD14 is increased in bronchoalveolar lavage of active sarcoidosis and correlates with alveolar macrophage membrane-bound CD14
I Striz, L Zheng, YM Wang, H Pokorna, PC Bauer and U Costabel
Immunology Unit, Institute of Chest Diseases, Prague, Czech Republic.
CD14 is a myeloid differentiation antigen which exists in a membrane- bound
(55 kD) and a soluble (48 kD) form. This antigen is a receptor for
lipopolysaccharide (LPS) structures and triggers the production of various
cytokines. The aim of this study was to evaluate whether in active
sarcoidosis, a disease with increased proportions of alveolar macrophages
(AM) with CD14 expression in BAL fluid, the soluble form of CD14 (sCD14) is
also increased. The sCD14 levels were measured in BAL fluid with an ELISA,
and membrane-bound CD14 was determined by an immunoperoxidase assay, in
active sarcoidosis (n = 13), inactive sarcoidosis (n = 9), idiopathic
pulmonary fibrosis (IPF) (n = 6), and control subjects (n = 8). Higher
concentrations of sCD14 were present in BAL fluid of patients with active
sarcoidosis (58 +/- 34 ng/ml) than in those with inactive disease (13 +/-
10 ng/ml), patients with IPF (5 +/- 5 ng/ml), or control subjects (10 +/-
8% ng/ml) (p < 0.01). Similarly, the proportions of AM expressing
membrane-bound CD14 were increased in active sarcoidosis (91 +/- 6%)
compared with inactive sarcoidosis (82 +/- 6%), patients with IPF (76 +/-
13%), and control subjects (79 +/- 9%) (p < .05). In sarcoidosis, a
significant correlation was found between the sCD14 concentration in BAL
fluid and AM membrane expression of CD14 (r = 0.57, p < 0.01). We
conclude that sCD14 is increased in BAL of active sarcoidosis suggesting a
potential role for this substance as marker of activity and in the
pathogenesis of pulmonary sarcoidosis.
