Sympathetic Nervous System Function In Psoriasis: A Possible Neuroimmunologic Pathogenesis

¹Hanan A. Salem, ¹Shaymaa El-Mongy, ²Samia Nassar, ³Mohamed El-Khatib, ⁴Eman El-Nashar, ⁵Azza Abd El-Baky and ⁵Elham R. Abd EL-Sameea

Departments of: Dermatology and Venereology, ¹Al-Mansoura Faculty of Medicine and ²Tanta Faculty of Medicine, Departments of: ³Neurology and ⁵Clinical Pathology, Al-Mansoura Faculty of Medicine and Department of ⁴Histology and Cytology, Benha Faculty of Medicine, Egypt.

Emotional stress is one of the most powerful precipitating factor in psoriasis. However, the pathomechanism whereby psychological factors precipitate the disease are totally unknown. Research is now underway to examine the interaction between the endocrine, nervous, and immune systems. The aim of the study was to assess the function of sympathetic nervous system, to detect the density of nerve fibres in lesional skin and to determine the number of NK cells in the peripheral blood of patients with psoriasis. Twenty psoriasis patients and 10 normal healthy control subjects were included in the study. For each subject, plasma noradrenaline was determined by ELISA, and serum dopamine b hydroxylase by Sympath TM25 enzymatic assay. The sympathetic skin response (SSR) was examined. The density of skin nerve fibres was evaluated by detection of neurofilaments immunohistochemically. Assessment of natural killer (NK) cells in the peripheral blood was done by using specific monoclonal antibodies to CD16 and measured by flow cytometry. There was significant increase in plasma noradrenaline, serum dopamine b hydroxylase, NK (CD16) cells in peripheral blood in patients than in control. Moreover, there was an increase in nerve fibres at the dermo-epidermal junction and in the papillary dermis, in lesional psoriatic skin than in control normal skin. However, there was no significant changes in the values of latency or the amplitude of SSR in patients than in control. We concluded that the sympathetic nervous system might have a particular role in the pathogenesis of psoriasis possibly via enhanced sympathetic activity which may lead to immune changes.