Evaluation of Bronchoalveolar Lavage Fluid Phospholipids and Cytokine Release by Alveolar Macrophages as Prognostic Markers in Sarcoidosis

Abstract

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-α: 1.5 ng/ml/10⁶(0.08–8.6), IL-6: 5.75 ng/ml/10⁶ (1.7–22.5)] and a significant decrease in BALF phospholipids [total lipid phosphorus (TLP): 29.9 µmol/l (13.8–68.3) as compared to 67.5 µmol/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-α and IL-6 release by AM, and close to normal phospholipid content in BALF. Conclusions: The level of TNF-α secretion by AM <3.9 ng/ml/10⁶ and total lipid phosphorus in BALF less than 30 µmol/l may serve as markers of poor prognosis in pulmonary sarcoidosis.