Mice with Nlrp3 mutations were developed independently by investigators in two laboratories. One group introduced a R258W mutation in the third exon of the Nlrp3 gene of C57BL/6 mice 9. This corresponds to the R260W mutation frequently found in humans

with the Muckle–Wells syndrome 7. A second group introduced either an A350V or an L351P mutation in exon BKM120 supplier 3 of Nlrp3 in 129SvJ mice 10. These mutations occur frequently in patients with Muckle–Wells syndrome and familial cold autoinflammatory syndrome, respectively 10. The targeting strategy used to obtain these strains required that the mice co-express Cre-recombinase to delete a neomycin cassette inserted in reverse orientation that when present causes gene silencing. This allowed studies of mice in which the Cre-recombinase was expressed under tissue-specific promoters and thus enabled tissue-specific expression of the mutated gene 10. In studies

to determine if the R258W mice exhibit the basic immunologic abnormality of patients with CAPS, BM-derived macrophages and BM-derived dendritic cells (BMDC) from these mice were stimulated with a TLR ligand (LPS) in the presence and absence of ATP, the latter an essential co-factor in NLRP3 inflammasome activation in WT cells. It was shown that while cells from R258W mice were unable to produce IL-1β and IL-18 in the absence of stimulation, they produced large amounts of these cytokines upon LPS stimulation in the presence or absence of exogenous ATP. These cells therefore differed from WT cells in that the latter only exhibited IL-1β production upon LPS stimulation in the presence of ATP and thus were similar to cells of patients Bcl-2 inhibitor aminophylline with CAPS. Interestingly, both WT and R258W cells produced equivalent amounts of other cytokines upon LPS stimulation. This suggested that the abnormality was limited to the NLRP3 inflammasome and that elevations in non-inflammasome cytokine production occurring during prolonged inflammation was due to secondary stimulation of cells by increased levels of IL-1β

6, 9. In parallel studies of peritoneal macrophages and BMDC from the A350V and L351P knock-in (KI) mice, production of IL-1β in the absence of ATP was also found. In addition, it was shown that BMDC from L351P mice secreted IL-1β when incubated at 32°C, as do CAPS patients with similar mutations. Thus, cold conditions seem to be an inflammasome activator in the presence of this mutation. Finally, cold-challenged dendritic cells from L351P KI mice exhibited spontaneous IL-1β secretion, whereas A350V KI cells were more dependent on LPS priming; this may explain the greater neonatal mortality of the L351P KI mice when compared with A350V KI mice 10. The mechanism of ATP co-activation of the NLRP3 inflammasome was studied in the R258W KI mice. Previous work has shown that this ATP function is an extracellular activity that involves activation of a membrane receptor, P2X7R 11.

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.