ASSOCIATION OF CUTANEOUS MAST-CELLS AND SENSORY NERVES WITH PSYCHIC STRESS IN PSORIASIS

Association of stress with psoriatic skin symptoms was studied in 13 p atients with psoriasis by dividing the patients into low- and high-str ess groups based on their clinical examination and answers to three qu estionnaires (General Health Questionnaire, a somatization scale, and a life change questionnaire). This study focused on skin mast cells an d sensory nerves which are the principal components in neurogenic infl ammation. Mast cells were stained enzyme-histochemically for tryptase and chymase, and neuropeptides substance P (SP), vasoactive intestinal peptide (VIP), and calcitonin gene-related peptide (CGRP) were demons trated immunohistochemically. Compared to the low-stress group (n = 7) , the patients in the high-stress group (n = 6) had more severe skin a nd joint symptoms. Furthermore, mast cells positive for chymase activi ty were prominently reduced, but tryptase-positive mast cells only sli ghtly decreased in the lesional skin of the high-stress group. A simil ar tendency was also observed in the nonlesional skin. In the papillar y dermis of the lesional skin, both VIP- and CGRP-immunoreactive nerve s could be observed in the high-stress group whereas in the low-stress group these nerve fibers were hardly visible in the corresponding are a. No association of SP with stress was observed. This study suggests that psychic stress is associated with exacerbation of psoriasis, and stress may induce alterations in the psoriatic lesions by increasing t he neuropeptide content with a concomitant decrease in the activity of neuropeptide-degrading enzymes, especially mast cell chymase.