Increase in Vitamin D but not Regulatory T Cells following Ultraviolet B Phototherapy of Patients with Atopic Dermatitis.

This study investigated serum 25-hydroxyvitamin D (25(OH)D) concentrations and circulating regulatory T cells in patients with atopic dermatitis receiving narrow-band ultraviolet B (nbUVB) phototherapy. Thirty adult patients with atopic dermatitis were included. Blood samples were collected at baseline and at weeks 2 and 4 of nbUVB phototherapy. Skin biopsies were taken at baseline and at week 4. Serum 25(OH)D concentrations increased significantly following nbUVB phototherapy (estimate of change from baseline to week 2: 32.00 nmol/l, confidence interval (CI) 20.48-43.52, p < 0.0001, n = 25; and from baseline to week 4: 50.30 nmol/l, CI 37.28-63.33, p < 0.0001, n = 18). This increase was independent of the filaggrin gene FLG loss-of-function mutation status. Flow cytometry showed no significant change in regulatory T cells or cytokine profiles of T cells in blood. Real-time quantitative PCR showed no change in skin cytokine levels. In conclusion, nbUVB phototherapy was associated with increased serum 25(OH)D concentrations, but not changes in circulating regulatory T cells in patients with atopic dermatitis.

Differential effects of phototherapy, adalimumab and betamethasone-calcipotriol on effector and regulatory T cells in psoriasis.

BACKGROUND: Psoriasis is a chronic T-cell-mediated skin disease with marked social and economic burdens. Current treatments are unsatisfactory, with unpredictable remission times and incompletely understood modes of action. Recent advances in our understanding of the pathogenesis of psoriasis have identified the imbalance between CD4+ T effector cells, particularly the T helper (Th)17 subset, and regulatory T cells (Tregs) as key to the development of psoriatic lesions, and therefore a novel therapeutic target. OBJECTIVES: To quantify in patients the effects of three commonly used psoriasis treatment modalities on the Th1, Th2, Th17 and Treg subsets, and to test whether any change correlates with clinical response. METHODS: Flow cytometry was used to enumerate Th1, Th2, Th17 and Treg subsets in blood and skin of patients with psoriasis before and after receiving any of the following treatments: narrowband ultraviolet B (NB-UVB), adalimumab and topical betamethasone-calcipotriol combination (Dovobet® ) RESULTS: All patients responded clinically to the treatments. NB-UVB significantly increased the numbers of circulating and skin Tregs, while, by contrast, adalimumab reduced Th17 cells in these compartments, and Dovobet had dual effects by both increasing Tregs and reducing Th17 cells. CONCLUSIONS: The differential effects reported here for the above-mentioned treatment modalities could be exploited to optimize or design therapeutic strategies to overcome the inflammatory drivers more effectively and restore the Th17-Treg balance in psoriasis.

Influence of the season on vitamin D levels and regulatory T cells in patients with polymorphic light eruption.

The exact mechanisms of photohardening in polymorphic light eruption (PLE) are still unknown, but medical photohardening was shown to increase regulatory T cell (Treg) numbers in the blood of PLE patients, similar to natural hardening. Furthermore, oral vitamin D supplementation increased peripheral Tregs in healthy individuals. We herein report on a post hoc analysis of 26 screened PLE patients of a clinical trial (ClinicalTrials.gov No. NCT01595893), in which the influence of the progressing season was investigated on baseline CD4+CD25+FoxP3+CD127- Treg numbers by flow cytometry and Treg suppressive function by co-culture assays with T effector cells as a secondary endpoint, together with 25-hydroxy vitamin D (25(OH)D) serum levels at the study's screening visit, taking place in the period from January to June. The mean 25(OH)D serum level of all patients was 33.2 ng ml(-1). Ten of those patients (38.5%) were identified with low 25(OH)D levels (<30 ng ml(-1)). Significantly higher baseline 25(OH)D serum levels (plus 34.4%; P = 0.0182) as well as higher relative Treg percentages in CD4+ population (plus 62.8%; P = 0.0157) and in total lymphocyte population (plus 59.6%; P = 0.0372) and higher absolute Treg numbers (plus 100.2%; P = 0.0042) were observed in the late spring/early summer period (April to June) compared to the winter period (January to February). No significant relationship was observed when Treg numbers and function were correlated with 25(OH)D levels. These data indicate that in PLE patients Treg numbers and their suppressive function are independent of vitamin D serum levels and suggest that UV light and/or other seasonal factors may affect these cells via the non-vitamin D related pathway(s).

EMSA Eritin Drives Expansion of Regulatory T Cells and Promotes T Cells Differentiation in Irradiated Mice.

Sublethal irradiation therapy in cancer treatment causes generalized immunosuppression, which results in a range of DNA damage. We examined the significance of a polyherbal medicine called "EMSA Eritin" on immunological responses in sublethally irradiated mice focusing on the involvement of Treg, naïve T cell, and also the development and differentiation of T cells in thymus. Normal BALB/c mice were sublethally irradiated with dose of 600 rad. The irradiated mice were then orally administered by EMSA Eritin once a day at different doses: 1.04, 3.12, 9.37 mg/g body weight. The treatment was performed for 14 days. On day 15, immunological responses were observed by analyzing the status of Treg and differentiation of T cells in thymus. The administration of EMSA Eritin to irradiated mice resulted in a significant increase of pre T cells, Treg cells, and naïve T cells, which in general could maintain and normalize healthy condition in mice.

Recovery Profiles of T-Cell Subsets Following Low-Dose Total Body Irradiation and Improvement With Cinnamon.

PURPOSE: Inefficient T-cell reconstitution from x-ray-induced immune damage reduces antitumor response. To understand the profile of T-cell reconstitution after irradiation will overcome the barrier of antitumor immunity. This study aimed to identify the recovery profile of T-cell subsets following x-ray irradiation and to highlight the role of cinnamon on efficient T-cell restoration postexposure in the antitumor response. METHODS AND MATERIALS: CD3(+), CD8(+), and CD4(+) T cells and Th1, Th2, Th17, and regulatory T (Treg) cells were evaluated at different time points after single low-dose total body irradiation (SLTBI) with or without cinnamon treatments. T-bet, GATA3, RORγt, and Foxp3 signaling specific for Th1, Th2, Th17, and Treg were also analyzed by RT-PCR assay. The effects of cinnamon on efficient T-cell subset reconstitution was confirmed in a lung melanoma model in irradiated mice. RESULTS: Reconstitution of CD4(+) T cells was delayed more than that of CD8(+) T cells in T-cell restoration after SLTBI. The production of IFNγ by Th1 or Tc1 cells was sharply decreased and was accompanied by reduced T-bet mRNA, even when total T-cell numbers had recovered; the frequencies of Th17 and Treg cells and their specific transcription factors (RORγt and Foxp3, respectively) were obviously increased. Irradiation-induced inefficient T-cell reconstitution impaired the antitumor capacities in the lung melanoma model. Pretreatment with cinnamon in irradiated mice accelerated the generation of Th1 and reduced the differentiation of Treg cells by activating T-bet and limiting transcriptions of Foxp3. Improvement resulting from cinnamon pretreatment on the efficient T-cell recovery profile from SLTBI promoted antitumor immunity in the lung melanoma model. CONCLUSIONS: T-cell reconstitution from SLTBI was characterized by impaired Th1 and elevated Th17 and Treg cells. Cinnamon effectively improved the imbalance of T-cell subsets by promoting the proliferation of Th1 and by suppressing expansions of Th17 and Tregs. The role of cinnamon in efficient T-cell reconstitution from SLTBI is effective in antitumor immunity.

Ultraviolet B light attenuates the systemic immune response in central nervous system autoimmunity.

OBJECTIVE: Environmental conditions (eg, latitude) play a critical role in the susceptibility and severity of many autoimmune disorders, including multiple sclerosis (MS). Here, we investigated the mechanisms underlying the beneficial effects of immune regulatory processes induced in the skin by moderate ultraviolet B (UVB) radiation on central nervous system (CNS) autoimmunity. METHODS: Effects of UVB light were analyzed in a murine model of CNS autoimmunity (experimental autoimmune encephalomyelitis). Additionally, patients with relapsing-remitting MS were treated with narrowband UVB phototherapy. Immunomodulatory effects were examined in skin biopsies, serum samples, and immune cells of the peripheral blood. RESULTS: Regulatory T cells (Tregs), which are induced locally in the skin-draining lymph nodes in response to UVB exposure, connect the cutaneous immune response to CNS immunity by migration to the sites of inflammation (blood, spleen, CNS). Here, they attenuate the inflammatory response and ameliorate disease symptoms. Treg-inducing tolerogenic dendritic cells (DCs) were further necessary for induction of this systemic immune regulation by UVB radiation, because ablation of Langerhans cells abolished the UVB-induced phenotype. MS patients treated with UVB phototherapy showed an increase in induced Tregs and tolerogenic DCs accompanied by the downregulation of the T-cell effector cytokine interleukin 21. The treatment further induced elevated serum levels of vitamin D. INTERPRETATION: Local UVB radiation of the skin influences systemic immune reactions and attenuates systemic autoimmunity via the induction of skin-derived tolerogenic DCs and Tregs. Our data could have implications for the understanding or therapeutic modulation of environmental factors that influence immune tolerance.

Photohardening of polymorphic light eruption patients decreases baseline epidermal Langerhans cell density while increasing mast cell numbers in the papillary dermis.

The pathogenesis of polymorphic light eruption (PLE) has been linked to a lack of UV-induced immune suppression. To determine the role of Langerhans cells (LC), mast cells and regulatory T cells, biopsies from PLE patients were taken from exposed sites in spring before and after photohardening with 311 nm or PUVA as well as again in summer. Skin sections were assessed for the presence of Langerin/CD1a+ LC and CD3+, CD4+, CD25+ or FoxP3+ T cells and mast cells. Photohardening transiently decreased the density of epidermal LC and significantly increased a low baseline mast cell density in the papillary dermis of PLE patients. Baseline T cell numbers in the skin were low, and there was no difference in PLE patients among any time point. This suggests that LC suppression together with recruitment of mast cells into photohardened skin may be a key cellular event underlying the mechanism by which phototherapy protects from PLE.

Changes in 1,25-dihydroxyvitamin D and 25-hydroxyvitamin D are associated with maturation of regulatory T lymphocytes in patients with chronic pancreatitis: a randomized controlled trial.

OBJECTIVES: We studied the impact of changes in 25-hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D (1,25(OH)(2)D) on regulatory T lymphocytes (Tregs) in patients with chronic pancreatitis (CP) and fat malabsorption in a prospective clinical trial. METHODS: The patients were randomized to 1 of 3 treatments during 10 weeks: weekly UV-B in a tanning bed (group A), 1520-IU/d vitamin D supplement (group B), or placebo (group C). A placebo tanning bed was used in groups B and C. We determined the levels of CD4 Tregs (CD3(+)CD4(+)CD25(+)CD127(low)FoxP3(+)) and CD8(+) Tregs (CD3(+)CD8(+)CD25(+)CD127(low)FoxP3(+)), together with 25OHD and 1,25(OH)2D. For baseline comparisons, we included 8 healthy individuals. Of the 30 included patients, 27 (group A, 7 patients; group B, 9 patients; and group C, 11 patients) completed the protocol. RESULTS: The baseline levels of CD4(+) Tregs relative to total CD4(+) count were higher in 22 patients with CP compared with healthy controls (2.8% vs 1.9%, P < 0.05) and were comparable for CD8+ Tregs (0.13% vs 0.05%, P = 0.3). Increases in levels of CD4(+) Tregs correlated to changes in 1,25(OH)(2)D (2% per 100 pmol/L, P = 0.002) and 25OHD (3% per 100 nmol/L, P = 0.01). CONCLUSIONS: Patients with CP have elevated relative levels of CD4(+) Tregs. Increases in 25OHD and 1,25(OH)(2)D were both related with increases in levels of Tregs.

8-Methoxypsoralen plus UVA treatment increases the proportion of CLA+ CD25+ CD4+ T cells in lymph nodes of K5.hTGFß1 transgenic mice.

8-Methoxypsoralen plus UVA (PUVA) photochemotherapy is an effective treatment for many skin diseases including psoriasis. However, its exact mechanism of therapeutic action is incompletely understood. Previously, in K5.hTGFß1 transgenic psoriatic mice, we found that PUVA induces Foxp3+ CD25+ CD4+ regulatory T cells in both lymph node and spleen. Now, in the same model, we investigated whether cutaneous lymphocyte-associated antigen (CLA) mediates PUVA's effect on homing of CD25+ CD4+ T cells to the lymph nodes of K5.hTGFß1 transgenic mice. We found that a low dose of topical PUVA maximally increased the proportion of CLA + CD25+ CD4 + T cells in the lymph nodes by up to 8-fold. We also observed an increased number of Foxp3+ CD25+ T cells in the skin of the mice after PUVA treatment. Together, these findings suggest that PUVA affects the homing of regulatory T cells.

Efficacy of excimer light therapy (308 nm) for palmoplantar pustulosis with the induction of circulating regulatory T cells.

In this open-label study, we investigated the efficacy of excimer light (308 nm) with a filter to cut off wavelengths below 297 nm for the treatment of palmoplantar pustulosis (PPP). Twenty patients with PPP were recruited and treated once a week for a total of 30 sessions. Patient response was assessed every 10 sessions based on the Palmoplantar Pustulosis Area and Severity Index (PPPASI) score. Levels of Th17 cells and regulatory T cells (Treg) in the peripheral blood in patients with PPP were also evaluated. Mean PPPASI score was 19.5 at baseline, 13.2 at 10 treatments, 10.9 at 20 treatments and 9.5 at 30 treatments. Th17 levels after excimer therapy were not significantly different from those at baseline. In contrast, Treg levels after excimer therapy were significantly higher than those at baseline.

8-methoxypsoralen plus ultraviolet A therapy acts via inhibition of the IL-23/Th17 axis and induction of Foxp3+ regulatory T cells involving CTLA4 signaling in a psoriasis-like skin disorder.

To elucidate the molecular action of 8-methoxypsoralen plus UVA (PUVA), a standard dermatological therapy, we used K5.hTGF-beta1 transgenic mice exhibiting a skin phenotype and cytokine abnormalities with strong similarities to human psoriasis. We observed that impaired function of CD4+CD25+ regulatory T cells (Tregs) and increased cytokine levels of the IL-23/Th17 pathway were responsible for the psoriatic phenotype in this mouse model. Treatment of K5.hTGF-beta1 transgenic mice with PUVA suppressed the IL-23/Th17 pathway, Th1 milieu, as well as transcription factors STAT3 and orphan nuclear receptor RORgammat. PUVA induced the Th2 pathway and IL-10-producing CD4+CD25+Foxp3+Tregs with disease-suppressive activity that was abolished by anti-CTLA4 mAb treatment. These findings were paralleled by macroscopic and microscopic clearance of the diseased murine skin. Anti-IL-17 mAb treatment also diminished the psoriatic phenotype of the mice. This indicated that both induced Tregs involving CTLA4 signaling and inhibition of the IL-23/Th17 axis are central for the therapeutic action of PUVA.

Ultraviolet light-induced regulatory (suppressor) T cells: an approach for promoting induction of operational allograft tolerance?

Ultraviolet (UV) light is known to induce skin cancers by causing DNA gene mutations and inducing immunosuppression. Taking advantage of these immunosuppressive capacities, UV light has been used, with different modalities, as an immunosuppressive therapy in a variety of diseases including allograft rejection and graft-versus-host disease. Phototherapy includes UVB irradiation, UVA irradiation, oral psoralen (+)UVA irradiation (PUVA), photodynamic therapy, and extracorporeal photopheresis, which consists of infusion of UVA-irradiated autologous leukocytes collected by apheresis and incubated with 8-methoxypsoralen. According to numerous experimental models and human data, there is increasing evidence that UVB irradiation and extracorporeal photopheresis can induce regulatory T cells and anticlonotypic activity. These therapies induce apoptosis of activated T cells or of extracorporally treated mononuclear cells, and up-regulate the expression of costimulary molecules and adhesion molecules on antigen presenting cells. UVB- or UVA-induced apoptotic cells could secrete immune suppressive cytokines (interleukin (IL)-4, IL-10). The processing and presentation of apoptotic T cell antigens from clones of pathogenic T cells by activated antigen presenting cells might explain the induction of systemic anticlonotypic activity by photopheresis. This induction of cell-mediated suppressive activity opens up future prospects with the aim of expanding regulatory T cells and/or anticlonotypic activity, especially by photopheresis in organ and cell transplantation.

Effects of a novel azaspirane (SK&F 105685) on arthritic lesions in the adjuvant Lewis rat: attenuation of the inflammatory process and preservation of skeletal integrity.

OBJECTIVE: To determine the effects of SK&F 105685 (N,N-dimethyl-8,8-dipropyl-2-azaspiro[4.5] decane-2-propanamine dihydrochloride) on the arthritic lesions in the tibiotarsal joint of adjuvant arthritic (AA) rats. METHODS: Inhibition of hindpaw inflammation was measured by water displacement. The protective effects on joint integrity were determined by measuring radiographic and histological changes and by scanning electron microscopy. RESULTS: Compared to AA control rats, SK&F 105685 suppressed hindpaw edema 64% or 41-54% in AA rats receiving 30 or 20 mg/kg/day, respectively. Radiographic evaluation showed marked decreases in soft tissue swelling and in the severity of skeletal tissue loss at the tibiotarsal joint in both dose groups. Histologically SK&F 105685 markedly attenuated the extent and severity of the inflammatory lesion and preserved the basic integrity of bone and cartilaginous tissues, including the content and distribution of proteoglycans of the articular cartilages. Cellular changes included decreases in the inflammatory infiltrate and in the number of osteoclasts and chondroclasts. Whereas AA control rats exhibited marked to severe loss (41-70%) of skeletal tissue mass, the loss in rats given 30 mg/kg SK&F 105685 was mild (< 20%). Scanning electron microscopy of the talus revealed only slight erosion of the articular cartilage and general preservation of the underlying bone. In contrast, in AA controls, there was marked erosion of the talar articular cartilage and severe loss of subchondral bone. Spleen cells from SK&F 105685 treated rats had a reduced capacity to respond to concanavalin A and contained suppressor cell activity as measured in a coculture assay. CONCLUSION: Our studies show that SK&F 105685 has remarkable protective effects on the joints of AA rats and suggests that it may attenuate the overall inflammatory process and retard the degenerative loss of skeletal tissue in rheumatoid arthritis in humans.

Ultraviolet radiation induces differential calcium signals in human peripheral blood lymphocyte subsets.

Ultraviolet (UV) irradiation is known to suppress normal lymphocyte function, which allows UV phototherapy for a variety of applications. Although UV radiation is well known to cause DNA damage, recent findings indicate that UV irradiation can activate cellular signal-transduction processes. We have previously found that UV induces tyrosine phosphorylation in lymphocytes in a dose- and wavelength-dependent manner and also induces Ca2+ signals in Jurkat T cells via tyrosine phosphorylation of PLC gamma 1 and associated proteins. In this study, normal human lymphocyte subsets were examined for UV-induced Ca2+ responses. CD4+ and CD8+ T cells gave strong responses, whereas other cells did not. Although B cells did not have substantial Ca2+ signals, the pattern of UV-induced tyrosine phosphorylation was very similar to that observed after surface immunoglobulin cross-linking. We propose that the inhibitory effect of UV on lymphocyte function may be due in part to an active induction of tyrosine phosphorylation and Ca2+ signals by a process that bypasses normal receptor control.

Systemic immunosuppression of cell-mediated immune reactions by a monofunctional psoralen plus ultraviolet A radiation.

Because of the undesirable side effects associated with the use of 8-methoxypsoralen and long-wave ultraviolet A (UVA) radiation in the treatment of skin disorders such as psoriasis, the use of monofunctional psoralens, which are less erythemogenic, less mutagenic, and generally non-phototoxic, has received considerable attention. Little is known, however, about the immunosuppressive properties of monofunctional psoralens. The purpose of this study was to examine the effect of parenteral administration of a monofunctional psoralen, angelicin, plus exposure to UVA radiation on the immune response. Injection of angelicin followed by exposure to UVA radiation significantly suppressed delayed-type hypersensitivity to alloantigen in a dose-dependent fashion. Similarly, the capacity of spleen cells from the angelicin and UVA-treated animals to proliferate to alloantigen was significantly suppressed. The suppression was specific for the alloantigen used to sensitize the angelicin and UVA-treated animals and was associated with the appearance of splenic antigen-specific suppressor T lymphocytes. These data demonstrate that the effect of systemic administration of a monofunctional psoralen followed by UVA exposure on the immune response is similar to that seen following the injection of bifunctional psoralens. These findings also suggest that the severe skin phototoxicity associated with the use of a bifunctional psoralen and UVA radiation is not necessary for the induction of systemic immuno-suppression. Furthermore, the induction of systemic antigen-specific immunosuppression by angelicin plus UVA, without overt skin phototoxicity, suggests the possibility of using this and related compounds to specifically inhibit unwanted immune reactions.

Immunological consequences of ultraviolet radiation exposure.

Depending on the dose and conditions of administration, ultraviolet radiation (UVR) can function as either a complete carcinogen, a co-carcinogenic agent, or an immunologic modulator. Although much is known about its carcinogenic properties, only recently have investigations been aimed at defining the mechanisms by which UVR mediates its effect on the immune system. The objective of this article is to present the necessary background and results of recent studies that provide the basis for defining some of the local and systemic effects that UVR has on an individual's immunologic potential. This discussion focuses on: the histologic alterations in the skin and draining lymph nodes, the changes in lymphocyte localization, the increased release of the immunologic (and physiologic) mediator ETAF/IL-1, and the induction of antigen-specific immunoregulatory circuits that occur subsequent to UVR exposure. It is our hypothesis that the detrimental effects that UVR has on the host's immunologic competence may represent a normal defense mechanism to protect the individual against the adverse consequences of chronic inflammatory stimuli. In this regard, a better understanding of photoimmunology may lead to the development of more effective means of immunologic modulation for altering the clinical course of various human diseases that are either immunologically mediated, photoinduced, or responsive to phototherapy.

Regulation of naturally occurring autoantibody secretion by a radiosensitive lymphocyte: initial characterization and ontogeny.

Low level irradiation (400-500 R) of normal mice or of murine spleen cells resulted in the detection of an enhanced number of plaque-forming cells against bromelain-treated autologous red cells (Br MRBC) 1 day later. The mechanism responsible for the increased numbers of plaques is apparently the elimination of a suppressor T cell since the addition of thymocytes or of Lyt 1+2+ splenic cells to cultures of irradiated cells reversed the radiation-induced increase. Studies on the ontogeny of the phenomenon indicate that anti-Br MRBC plaques can be formed by spleen cells taken from mice shortly after birth although adult levels are not reached until after 3 weeks of age. Radiation-induced increases in the number of plaques were not seen until 3 weeks of age, thus, suggesting a temporal developmental sequence of the ability to produce autoantibodies and to regulate such production.

Systemic suppression of contact hypersensitivity in mice by psoralen plus UVA radiation (PUVA).

Treatment of mice with 8-methoxypsoralen plus longwave UV radiation (UVA, 320-400 nm) decreased their response to contact sensitizers applied subsequently to unirradiated skin. This decreased reactivity exhibited a delayed time course, it affected the afferent but not the efferent phase of the reaction, and it was associated with the development of splenic suppressor cells. These suppressor cells were antigen-specific T lymphocytes, and they prevented the induction, but not the elicitation, of contact hypersensitivity in recipient mice. In all of these characteristics, the decreased reactivity induced by treatment with psoralen plus UVA radiation (PUVA) resembled that produced by UV radiation of shorter wavelengths (less than 320 nm). These studies suggest that PUVA treatment may initiate the same sequence of cellular events as does exposure to sunlamp (UVB, 280-320 nm) radiation, leading to preferential activation of the suppressor cell pathway.