Evaluation of bronchoalveolar lavage fluid phospholipids and cytokine release by alveolar macrophages as prognostic markers in sarcoidosis

Background: The clinical course of sarcoidosis is unpredictable and reliable laboratory prognostic parameters are lacking.

Objectives: The aim of the present study was to estimate the prognostic value of bronchoalveolar lavage fluid (BALF) phospholipids and cytokine production by alveolar macrophages (AM) in pulmonary sarcoidosis.

Methods: We investigated BALF parameters in 64 subjects (55 patients with sarcoidosis and 9 healthy volunteers as controls). After a period of 12 months, the total sarcoidosis study population was divided into three groups according to radiological, functional and laboratory dynamics: the group with a favorable (n = 15), the one with an unfavorable (n = 16) and the one with an intermediate clinical course of the disease (n = 24).

Results: The group of patients with a poor clinical outcome was characterized by a lower percentage of lymphocytes in BALF [20% (4-56%)], rather small amounts of cytokines [TNF-alpha: 1.5 ng/ml/10(6 )(0.08-8.6), IL-6: 5.75 ng/ml/10(6) (1.7-22.5)] and a significant decrease in BALF phospholipids [total lipid phosphorus (TLP): 29.9 micromol/l (13.8-68.3) as compared to 67.5 micromol/l (33.2-127.2) in controls]. Patients with a favorable clinical outcome were shown to have higher lymphocytosis (40%, range 6-64, p < 0.05 versus poor outcome), intensive TNF-alpha and IL-6 release by AM, and close to normal phospholipid content in BALF.

Conclusions: The level of TNF-alpha secretion by AM <3.9 ng/ml/10(6) and total lipid phosphorus in BALF less than 30 micromol/l may serve as markers of poor prognosis in pulmonary sarcoidosis.