Sarcoidosis is a multiorgan granulomatous disease of unknown etiology. The predominance of Th1‑related cytokines is observed in the bronchoalveolar fluid (BALF) in pulmonary sarcoidosis. Recently, Th17 cells have been postulated to be involved in the pathogenesis of sarcoidosis. Sarcoidosis is more prevalent in nonsmokers than in smokers. The exact effect of smoking on granulomatous inflammation in this disease remains unclear. The aim of the study was to evaluate the Th1/Th2/Th17‑related cytokine concentration in the BALF of patients with pulmonary sarcoidosis in relation to smoking status. The study included 74 patients with confirmed pulmonary sarcoidosis. Data on smoking status were available for 61 patients (26 ever‑smokers, 35 never‑smokers; mean 11 ±9.1 pack-years in smokers). The concentrations of interleukin (IL) 17A (IL‑17A), IL‑10, IL‑6, IL‑4, and IL‑2 as well as interferon γ (IFN‑γ) and tumor necrosis factor α (TNF‑α) were measured in BALF supernatants using a flow cytometry method--the Cytometric Bead Array. The median concentration of IL‑6, IFN‑γ, and IL‑17A (2.19 pg/ml, 1.28 pg/ml, and 6.08 pg/ml, respectively) did not differ significantly between smokers and nonsmokers. TNF‑α, IL‑10, IL‑4 and IL‑2 levels were below the detection limit in most patients. We observed a significant correlation between IFN‑γ concentration and the number of macrophages in BALF (r = 0.66, P <0.05) and between IL‑17A and IL‑6 levels (r = 0.94, P <0.05). We confirmed a significant role of IL‑6, IFN‑γ, and IL-17A in the local inflammatory response in sarcoidosis. However, the interpretation of the limited number of cytokine measurements should be made with caution. Further studies are needed to explain the effect of smoking on the pathomechanism of inflammation in sarcoidosis.

Airway resistance is the ratio of driving pressure to the rate of the airflow in the airways. The most frequent methods used to measure airway resistance are whole-body plethysmography, the interrupter technique and the forced oscillation technique. All these methods allow to measure resistance during respiration at the level close to tidal volume, they do not require forced breathing manoeuvres or deep breathing during measurement. The most popular method for measuring airway resistance is whole-body plethysmography. The results of plethysmography include among others the following parameters: airway resistance (Raw), airway conductance (Gaw), specific airway resistance (sRaw) and specific airway conductance (sGaw). The interrupter technique is based on the assumption that at the moment of airway occlusion, air pressure in the mouth is equal to the alveolar pressure . In the forced oscillation technique (FOT), airway resistance is calculated basing on the changes in pressure and flow caused by air vibration. The methods for measurement of airway resistance that are described in the present paper seem to be a useful alternative to the most common lung function test—spirometry. The target group in which these methods may be widely used are particularly the patients who are unable to perform spirometry.