Posttraumatic stress disorder is associated with elevated risk for inflammatory and autoimmune diseases. Regulatory T cells play a major role in maintaining homeostasis of the immune system by controlling the activity of effector cells and auto reactive T lymphocytes, thus controlling immunoreactivity. Regarding the role of regulatory T cells in inflammatory and autoimmune diseases, we hypothesized that PTSD patients might exhibit changes in composition of regulatory T cells in peripheral blood. For this purpose we have analyzed absolute numbers of T cells and CD4, CD8 subpopulations in peripheral blood of N=21 PTSD patients and N=22 healthy controls. Frozen samples of the same participants were later analyzed regarding regulatory T cell composition. Natural regulatory T cell (nTreg) population is characterized CD4+CD25+FOXP3+ phenotype. In addition to CD25 and FOXP3 nTreg cells express other markers which define different subpopulations of these cells. Mature nTreg express low levels of CD127 and HLA-DR (CD4+CD25+FOXP3+CD127+HLA-DR+). Terminally differentiated nTreg cells lose CD127 ((CD4+CD25+FOXP3+CD127-HLA-DR+) and have high expression of FOXP3. Induced regulatory T cells (iTreg) are characterized by low expression of CD127 and lack of HLA-DR marker. Their precursors pTreg cells do not express CD127 or HLA-DR. In addition to these markers we have analyzed the expression of CD39, membrane ectoenzyme which hydrolyzes extracellular ATP and ADP into AMP, an all of the Tregs subpopulations. Although PTSD patients have a lower number of T cells and T helper cells we found no differences in Tregs percentage and composition.

Temeljne medicinske znanosti