BAL is a valuable method in diagnostic pathway of pulmonary sarcoidosis. However, results of BALF examination must be interpreted considering a specific clinical case. BALF CD4/CD8 ratio depends on clinical and radiographic manifestation.

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Background: The mechanisms driving the transition from inflammation to fibrosis in sarcoidosis patients are poorly understood; prognostic features are lacking. Immune cell profiling may provide insights into pathogenesis and prognostic factors of the disease. This study aimed to establish associations in simultaneous of lymphocyte subset profiles in the blood, bronchoalveolar lavage fluid (BALF), and lung biopsy tissue in the patients with newly diagnosed sarcoidosis.Methods: A total of 71 sarcoid patients (SPs) and 20 healthy controls (HCs) were enrolled into the study. CD31, CD38, CD44, CD103 positive T lymphocytes in blood and BALF were analysed. Additionally, the densities of CD4, CD8, CD38, CD44, CD103 positive cells in lung tissue biopsies were estimated by digital image analysis. Results: Main findings: (I) increase of percentage of CD3 + CD4 + CD38 + in BALF and blood, and increase of percentage of CD3 + CD4 + CD44 + in BALF in Löfgren syndrome patients comparing with patients without Löfgren syndrome, (II) increase of percentage of CD3 + CD4 + 103 + in BALF and in blood in patients without Löfgren syndrome (comparing with Löfgren syndrome patients) and increase of percentage of CD3 + CD4 + 103 + in BALF and in blood in more advanced sarcoidosis stage. (III) Increasing percentage of BALF CD3 + CD4 + CD31 + in sarcoidosis patients when comparing with controls independently of presence of Löfgren syndrome, smoking status or stage of sarcoidosis. Several significant correlations were found. Conclusions: Lymphocyte subpopulations in blood, BALF, and lung tissue were substantially different in SPs at the time of diagnosis compared to HCs. CD3 + CD4 + CD31 + in BALF might be a potential supporting marker for the diagnosis of sarcoidosis. CD3 + CD4 + CD38 + in BALF and blood and CD3 + CD4 + CD44 + in BALF may be markers of the acute immune response in sarcoidosis patients. CD4 + CD103 + T-cells in BALF and in blood are markers of the persistent immune response in sarcoidosis patients and are potential prognostic features of the chronic course of this disease.

BackgroundSarcoidosis is associated with an increase in the number of alveolar T cells (CD3+ cells) and an increase of the CD3+CD4+ lymphocyte subset. However, the number of lymphocytes and the CD4/CD8 ratio in bronchoalveolar lavage (BAL) fluid are highly variable in sarcoidosis. Comparative studies have demonstrated that geographic and ethnic factors are linked to the specific characteristics of patients with sarcoidosis.Aim of the studyTo investigate peculiarities of BAL fluid (BALF) cell patterns in different clinical activity of pulmonary sarcoidosis at the time of diagnosis.Material and methodsA total of 308 non-treated patients (138 asymptomatic and 170 with sarcoidosis-related symptoms) and 40 previously empirically steroid-treated patients with newly diagnosed sarcoidosis have been prospectively examined.ResultsSignificant BAL fluid lymphocytosis and increased CD4/CD8 ratio were characteristic for all three sarcoidosis patient groups. A total of 12% of asymptomatic patients, 3% of patients with sarcoidosis-related symptoms, and 5% of previously treated symptomatic patients had normal BALF cell counts. Non-treated patients with sarcoidosis-related symptoms had significantly higher lymphocytosis (45±19% versus 39±17%, P<0.01), CD4/CD8 ratio (9.3±5.0 versus 5.7±4.5, P<0.001), and total BALF cell count (411±322 106/mL versus 334±273 106/mL, P<0.05), compared with asymptomatic patients. However, previously treated symptomatic patients had lower lymphocytosis (39±15% versus 45±19%, P=0.058), and total BALF cell count (292±166 106/mL versus 411±322 106/mL, P<0.05) compared with non-treated symptomatic patients. The same trend was noticed for CD4/CD8 ratio (8.3±4.8), although a statistically significant difference was not achieved.ConclusionsIndependently of clinical symptoms at the time of diagnosis sarcoid patients have significantly different BAL fluid cell patterns compared to healthy persons. BAL fluid cell changes are more prominent in corticosteroid non-treated patients with clinically active sarcoidosis. Treatment with systemic corticosteroids may modify typical BALF cellular patterns of sarcoidosis.