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Narrow band-ultraviolet B (NB-UVB) is an effective treatment for psoriasis. We aim to generate a potential mechanism of NB-UVB through comparing the transcriptomic profile before and after NB-UVB treatment between the peripheral edge of lesional skin (PE skin) and the center of lesional skin (CE skin) on the basis of molecular mechanisms of these two areas display different downstream functions. More than one-fourth of the NB-UVB-altered genes were found to be plaque-specific. Some of them were psoriasis signature genes that were downregulated by NB-UVB in, both, PE and CE skin (core alteration), such as IL36G, DEFB4A/B, S100A15, KRT16, and KRT6A. After NB-UVB treatment, the activity score of upstream cytokines, such as interferons, interleukin (IL)-6, IL-17, and IL-22 in pathogenesis decreased. In addition, NB-UVB could restore normal keratinization by upregulating LORICRIN and KRT2, particularly in the CE skin. Finally, we illustrated that NB-UVB is capable of suppressing molecules from the initiation to maintenance phase of plaque formation, thereby normalizing psoriatic plaques. This finding supports the usefulness of NB-UVB treatment in clinical practice and may help in the development of new treatment approaches in which NB-UVB treatment is included for patients with psoriasis or other inflammatory skin diseases.

Although TNF inhibitors have dramatically improved the outcome of patients with rheumatoid arthritis, 30-40% of patients do not respond well to them and treatment needs to be changed. In an effort to discriminate good and poor responders, we focused on the change in serum and synovial fluid levels of interleukin (IL-) 33 before and after treatment with TNF inhibitors. They were also measured in synovial fluids from 17 TNF inhibitor-naïve patients, and fibroblast-like synoviocytes (FLS) in-culture from 6 patients and correlated with various pro-inflammatory cytokines. Serum levels of IL-33 at 6 months after treatment decreased significantly in responders, while they did not change in non-responders. Synovial fluid levels of IL-33 in 6 patients under treatment with TNF inhibitors stayed high in 3 who were refractory and slightly elevated in 2 moderate responders, while they were undetectable in one patient under remission. Among inflammatory cytokines measured in 17 synovial fluids from TNF inhibitor-naïve patients, levels of IL-33 showed a significant positive correlation only to those of IL-1β. IL-1β increased IL-33 expression markedly in FLS in vitro, compared to TNF-α. IL-1β might be inducing RA inflammation through producing pro-inflammatory IL-33 in TNF inhibitor-hypo-responders. Sustained elevation of serum and/or synovial levels of IL-33 may account for a poor response to TNF inhibitors, although how TNF inhibitors affect the level of IL-33 remains to be elucidated.

Topical vitamin D3 has relatively recently been introduced for the treatment of psoriasis. Synthetic vitamin D3 analogues with a high potential for inducing differentiation of cells, but with a low hypercalcemic effect have recently been developed. One such synthetic analogue of 1,25-dihydroxyvitamin D3 (calcitriol), 22-oxacalcitriol (OCT), is a novel agent for the topical treatment of psoriasis. The activity of OCT in vitro was investigated and compared with that of a series of vitamin D3 analogues as to their ability to inhibit murine T lymphocyte proliferation stimulated by con-A, to suppress IL-6 and IL-8 production by keratinocytes stimulated with IL-1alpha and TNFalpha, and to inhibit AP-1- and NFkappaB-dependent reporter gene expression. OCT inhibited the proliferation of lymphocytes and suppressed IL-8 and IL-6 production by keratinocytes to the same extent as the other vitamin D3 analogues. It also inhibited AP-1- and NFkappaB-controlled luciferase activity to the same extent as the other vitamin D3 analogues, which demonstrates its mechanism of action in the suppression of inflammatory processes.