Narrowband–UVB irradiation decreases the production of pro-inflammatory cytokines by stimulated T cells

Abstract

Narrow-band ultraviolet B (UVB) phototherapy is an effective treatment for psoriasis. Owing to its limited penetration, the direct effects of UVB are mostly restricted to cells residing in the epidermis and papillary dermis, and are associated with epidermal depletion of Langerhans' cells (LC) and T cells. It has been argued that the depletion of the skin-resident T-cell population may be due to a combination of UVB-induced apoptosis and decreased recruitment from the blood due to lower expression of the required adhesion and homing molecules. We have previously demonstrated that UVB treatment can alter the expression of adhesion molecules by blood lymphocytes, and as these can be influenced by cytokines, the aim of this study was to investigate whether UVB irradiation can also influence the cytokine production of circulating T cells. Four patients with active chronic plaque psoriasis were treated daily with narrow-band 312 nm UVB irradiation and blood samples obtained before treatment and weekly thereafter for 2 weeks. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured with a streptococcal superantigen or a conventional streptococcal antigen preparation, and cell culture supernatants were assayed for various cytokines. When stimulated with the superantigen, PBMCs from UVB-treated psoriasis patients secreted greater amounts of the anti-inflammatory cytokine IL-10, and showed markedly decreased production of IL-1beta, IL-2, IL-5 and IL-6 compared to the pre-treatment values; the production of IFN-gamma, IL-8 and IL-12p70 were also decreased but did not reach statistical significance. Thus, the combination of UVB-induced apoptosis, increased secretion of anti-inflammatory cytokines and decreased trafficking to the skin may help to explain the beneficial effects of UVB treatment on psoriasis and why disease remission can sometimes be sustained for a prolonged period.

Epidermal Th22 and Tc17 Cells Form a Localized Disease Memory in Clinically Healed Psoriasis

“…Alternatively, activated T cells may continuously be recruited from circulation in patients after nb-UVB but not after biologics treatment. Taken the available data on circulating T cells during biologics (39,40) and nb-UVB treatment (41,42) it is not possible to predict whether replenishment of skin T cells occur in the different treatments. The inflammatory profiles in epidermal T cells may seem contradictory to previous publications where expression analysis of full skin biopsies 6 wk after nb-UVB treatment suggested normalization of IL17A and IL22 gene expression (43,44) and highlights the importance of dissecting different T cell populations present within the different anatomical compartments of the skin.…”

Progressive Extragenital Lichen Sclerosus Successfully Treated With Narrowband UV-B Phototherapy

“…6 Although its mechanism of action is not completely understood, it appears that NVUV-B has both anti-inflammatory and immunosuppressive effects. 7 While several reports and small case series have demonstrated the effectiveness of UV-A1 therapy (340-400 nm) for extragenital LS, 5,8,9 we could find no published studies in which NBUV-B (311-313 nm) was successfully or unsuccessfully used to treat this condition. Several studies have demonstrated that both UV-A1 and NBUV-B increase matrix-metalloproteinase levels in human skin and cultured dermal fibroblasts, 9-14 which may explain the effectiveness of UV-A1 in sclerosing skin diseases.…”

A Short Cycle of Narrow-Band UVB Phototherapy in the Early Phase of Long-Term Efalizumab Can Provide a Quicker Remission of Moderate and Severe Psoriasis: A Pilot Study

“…In addition, NB-UVB inhibits the release of proinflammatory cytokines [10, 11] and the expression of intercellular adhesion molecule 1 [9, 12]. Finally, NB-UVB isomerizes urocanic acid with a strong downregulatory activity on T-cell functions [13].…”