Treg/Th17 cell balance and phytohaemagglutinin activation of T lymphocytes in peripheral blood of systemic sclerosis patients

• Published in: World journal of experimental medicine 2017-08, Vol.7 (3), p.84-96
• Main Authors: Krasimirova, Ekaterina, Velikova, Tsvetelina, Ivanova-Todorova, Ekaterina, Tumangelova-Yuzeir, Kalina, Kalinova, Desislava, Boyadzhieva, Vladimira, Stoilov, Nikolay, Yoneva, Tsvetelina, Rashkov, Rasho, Kyurkchiev, Dobroslav
• Format: Article
• Language: English
• Subjects: Basic Study
• ISSN: 2220-315X; 2220-315X
• DOI: 10.5493/wjem.v7.i3.84

To investigate T-cell activation, the percentage of peripheral T regulatory cells (Tregs), Th17 cells and the circulating cytokine profile in systemic sclerosis (SSc). We enrolled a total of 24 SSc patients and 16 healthy controls in the study and divided the patients as having diffuse cutaneous SSc (dcSSc, = 13) or limited cutaneous SSc (lcSSc, = 11). We performed a further subdivision of the patients regarding the stage of the disease - early, intermediate or late. Peripheral venous blood samples were collected from all subjects. We performed flow cytometric analysis of the activation capacity of T-lymphocytes upon stimulation with PHA-M and of the percentage of peripheral Tregs and Th17 cells in both patients and healthy controls. We used ELISA to quantitate serum levels of human interleukin (IL)-6, IL-10, tissue growth factor-β1 (TGF-β1), and IL-17A. We identified a decreased percentage of CD3+CD69+ cells in PHA-stimulated samples from SSc patients in comparison with healthy controls (13.35% ± 2.90% 37.03% ± 2.33%, < 0.001). However, we did not establish a correlation between the down-regulated CD3+CD69+ cells and the clinical subset, nor regarding the stage of the disease. The activated CD4+CD25+ peripheral lymphocytes were represented in decreased percentage in patients when compared to controls (6.30% ± 0.68% 9.36% ± 1.08%, = 0.016). Regarding the forms of the disease, dcSSc patients demonstrated lower frequency of CD4+CD25+ T cells against healthy subjects (5.95% ± 0.89% 9.36% ± 1.08%, = 0.025). With regard to Th17 cells, our patients demonstrated increased percentage in comparison with controls (18.13% ± 1.55% 13.73% ± 1.21%, = 0.031). We detected up-regulated Th17 cells within the lcSSc subset against controls (20.46% ± 2.41% 13.73% ± 1.21%, = 0.025), nevertheless no difference was found between dcSSc and lcSSc patients. Flow cytometric analysis revealed an increased percentage of CD4+CD25-Foxp3+ in dcSSc patients compared to controls (10.94% ± 1.65% 6.88% ± 0.91, = 0.032). Regarding the peripheral cytokine profile, we detected raised levels of IL-6 [2.10 (1.05-4.60) pg/mL 0.00 pg/mL, < 0.001], TGF-β1 (19.94 ± 3.35 ng/mL 10.03 ± 2.25 ng/mL, = 0.02), IL-10 (2.83 ± 0.44 pg/mL 0.68 ± 0.51 pg/mL, = 0.008), and IL-17A [6.30 (2.50-15.60) pg/mL 0 (0.00-0.05) pg/mL, < 0.001] in patients when compared to healthy controls. Furthermore, we found increased circulating IL-10, TGF-β, IL-6 and IL-17A in the lcSSc subset control subjects, as it follows: IL-10 (3