Sun exposure induces rapid immunological changes in skin and peripheral blood in patients with psoriasis

Abstract

Our data show that clinical improvement of psoriasis following sun exposure is preceded by a rapid reduction in local and systemic inflammatory markers, strongly suggesting that immune modulation mediated the observed clinical effect. We cannot completely rule out that other mechanisms, such as stress reduction, may contribute, but it is extensively documented that UV irradiation is a potent inducer of immunosuppression and we therefore conclude that the observed effect was primarily due to sun exposure.

Effects of ultraviolet light on human serum 25-hydroxyvitamin D and systemic immune function

“…This study is the first to report narrowband UV-B increasing Treg cell numbers in human peripheral blood. However, the result is supported by the recent demonstration 22 of a relative increase in dermal FoxP3 1 cells in patients with psoriasis exposed to controlled natural sunlight. In contrast, a study of 9 patients with atopic dermatitis treated with narrowband UV-B failed to show a significant change in FoxP3 1 cells 40 in lesional skin.…”

“…20,21 In patients being treated with sunlight, PBMCs demonstrated reduced cytokine secretion and skin biopsies showed a relative increase in dermal FoxP3 cells. 22 Photochemotherapy, in which photosensitizing psoralen medication forms DNA adducts when combined with UV-A exposure (psoralen with UV-A), has also been shown to induce CD4 1 CD25 1 FoxP3 1 Treg cells in peripheral blood. 23,24 Although of great potential therapeutic interest, the links between human UV exposure, vitamin D levels, and immune function remain to be clearly established.…”

Positive Changes in Self-management and Disease Severity Following Climate Therapy in People with Psoriasis

“…The 3-week treatment programme includes individualized scheduled sun exposure, daily physical training, education about psoriasis, comorbidity and treatments, group discussions, psychosocial support and medical consultations. CT has been shown to reduce Psoriasis Area and Severity Index (PASI) by 75% (6), inter alia due to the sun-induced reduction in immune activity in psoriasis lesions (7,8). The therapy also increases the serum levels of vitamin D and reduces lipids (9).…”

Effect of weather and environmental factors on the clinical course of psoriasis: Table 1

“…Psoriasis is a chronic disease, the prevalence of which shows geographic variations,1 suggesting that it might be influenced by climatic factors such as sun exposure and humidity 2 3. In order to assess the effect of weather and both outdoor and indoor environmental factors on the clinical course of psoriasis, we analysed the answers given to a specific questionnaire administered to 300 consecutive patients attending the psoriasis outpatient clinic of our department.…”