Other studies show that balneotherapy with Dead Sea salt solution soaks in combination with NB-UVB therapy is superior to NB-UVB therapy alone [24, 25], which could be attributed to increased photosensitivity of the skin to UV radiation [26, 27]. We do not think that explains the results in our study for two reasons. As mentioned above, there are studies showing see more that bathing in the geothermal seawater without NB-UVB treatment has a beneficial clinical effect [1, 2]. In

addition, the cumulative dose of NB-UVB therapy in this current study was only 10 treatment sessions for patients bathing in geothermal seawater combined with NB-UVB therapy compared with 24 sessions for patients treated with NB-UVB therapy alone. However, the agents responsible for PD0332991 in vitro these beneficial effects of bathing in saline or thermal water have not been fully elucidated but most likely involve chemical [26, 28, 29], thermal [30], mechanical [2] and immunomodulatory effects [28, 31]. Furthermore, studies have shown that bathing in salt solutions has been associated with increased photosensitivity of the skin to UV radiation [26, 27]. Even though balneotherapy

and spa therapy are widely used, the immune modulatory mechanisms are only partly understood. Few studies have shown immunomodulatory effects on epidermal Langerhans cells, inhibition of Th1 differentiation and cytokine production from keratinocytes [28, 31]. One recent study from Korea [32] showed that thermal spring water

suppressed the expression of pro-inflammatory cytokines in human keratinocytes ‘in vitro’ as well as the differentiation of mouse CD4+ T cells into Th1, Th2 and Th17 cells. CCR4 has been found to be abundantly expressed on circulating T cells with a skin-homing CLA+ phenotype [33] in normal subjects as well as in patients with psoriasis [34], which is consistent with our results. In contrast, CCR10 and CD103 are weakly expressed in the peripheral blood of normal subjects and nearly undetected in normal skin [35, 36]. In addition, CCR10 is expressed by a minority (approximately 30%) of circulating CLA+ T cells [37]. However, both CCR10 and CD103 Tryptophan synthase have been found in the inflamed psoriatic lesions [35, 36]. Their involvement in the immunopathogenesis of psoriasis is further suggested by our findings demonstrating the increased proportion of circulating skin-homing CLA+ T cells co-expressing the tissue retention integrin CD103 and/or the chemokine receptors CCR4 and CCR10. More importantly, they had a positive correlation with the clinical improvements observed in the study, thus implicating the role of directing CCR4+/CCR10+ and CD103+ subset of skin-homing T cells (CLA+) into psoriasis plaques during the active stage of the disease. CLA+, CD103+ T cells, various adhesion molecules as well as activation markers did not change significantly during or after both treatment protocols.