Abstract and Introduction
Background: Psychological stress causes phenotypic changes in circulating lymphocytes and is regarded as an important trigger of the Th1-polarized inflammatory skin disease psoriasis.
Objective: To study the effects of psychological stress on immunological parameters, i.e. membrane molecules relevant to the pathophysiology of psoriasis, especially cutaneous lymphocyte-associated antigens (CLA) involved in T and natural killer (NK) cells homing in on the skin.
Methods: The severity of psoriasis was assessed in patients using the Psoriasis Area and Severity Index. Patients with psoriasis (n = 15) and healthy volunteers (n = 15) were exposed to brief psychological stress in the laboratory. In vitro analyses were conducted 1 h before, immediately following and 1 h after stress exposure. Peripheral T- and NK-cell subsets including CD8+ T lymphocytes, CLA+ lymphocytes and lymphocyte function-associated antigen type 1 (LFA-1)+ lymphocytes were analysed by flow cytometry.
Results: We found a significant stress-induced increase of CD3+ T lymphocytes in patients with psoriasis only. Analyses of T-cell subsets revealed that this increase was observable for cytotoxic CD8+ T lymphocytes and CLA+ CD3+ lymphocytes. The total number of circulating NK cells (CD16+, CD56+) increased immediately after stress in both groups whereas only patients with psoriasis showed a significant increase in CLA+ NK cells.
Conclusions: A higher stress-induced increase of CLA+ T and CLA+ NK cells in the circulation of patients with psoriasis might point to an increased ability of T and NK cells in the presence of psoriasis to home in on the skin during mental stress. Further studies are needed to verify these relationships in more detail and to investigate the time point at which these cells accumulate within lesional skin, and whether or not psychotherapy improves the quality of life of patients with psoriasis and influences stress-dependent parameters.
The current pathophysiological concept of psoriasis emphasizes the central role of immunological abnormalities. T cells are activated and home in on the psoriatic lesions before epidermal changes appear. The improvement gained by treatment with immunosuppressive agents underlines the central role of T cells in this disease. In addition, different study groups have found cells that express natural killer (NK) markers, NK-T cell markers in plaques of psoriasis[3,4] and a reduced number of circulating NK cells in psoriasis, suggesting a pathophysiological relevance for NK cells in psoriasis.
Previous studies suggest the existence of a brain-skin axis in psoriasis.[6,7,8,9] However, until now the different expression of membrane molecules by circulating lymphocytes after psychological stress has been studied in much more detail in patients with atopic dermatitis (e.g. Schmid-Ott et al.[8,9]) than in patients with psoriasis except for studies on NK cells and the CD11b+ subpopulation of CD8+ T cells. In this study we focus on the stress effects of T and NK cells in patients with psoriasis compared with healthy volunteers.
The British Journal of Dermatology. 2009;160(4):782-785. © 2009
Cite this: Immunological Effects of Stress in Psoriasis - Medscape - Apr 01, 2009.