Photo(chemo)therapy reduces circulating Th17 cells and restores circulating regulatory T cells in psoriasis

312 nm UVB Phototherapy Limits Atherosclerosis by Regulating Immunoinflammatory Responses in Mice

AIM

Our previous studies identified ultraviolet B (UVB) irradiation as a possible approach for preventing atherosclerosis. The aim of this study was to clarify the effect of 312 nm UVB, a wavelength similar to that of clinically available narrow-band UVB for the treatment of psoriasis, on atherosclerosis and the underlying mechanisms.

METHODS AND RESULTS

Using a recently developed UVB-light-emitting diode device, we irradiated 6-week-old male atherosclerosis-prone apolipoprotein E-deficient mice with 312 nm UVB at 5 or 10 kJ/m² and examined its effect on the development of atherosclerosis and immunoinflammatory responses by performing histological analysis, flow cytometry, biochemical assays, and liquid chromatography/mass spectrometry-based lipidomics. UVB irradiation at 10 kJ/m² but not at 5 kJ/m² significantly attenuated the development of aortic root atherosclerotic plaques, while UVB irradiation at both doses induced a less inflammatory plaque phenotype. This atheroprotective effect was associated with a reduced effector T cell number, a shift toward anti-atherogenic helper T cell responses, and increased proportion of regulatory T cells in lymphoid tissues and increased levels of proresolving lipid mediators in the skin.

CONCLUSIONS

We demonstrated that 312 nm UVB irradiation limits atherosclerosis by favorably modulating the T cell balance and lipid mediator profile. Our findings indicate that 312 nm UVB phototherapy could be an attractive immunomodulatory approach for preventing and treating atherosclerosis.

Diverse roles of dendritic cell and regulatory T cell crosstalk in controlling health and disease

Dendritic cells (DCs) are specialized antigen-presenting cells for lymphocytes, including regulatory T (Treg) cells, a subset of CD4+ T cells expressing CD25 and Foxp3, a transcription factor. Treg cells maintain immunological self-tolerance in mice and humans, and suppress autoimmunity and other various immune responses such as tumor immunity, transplant rejection, allergy, responses to microbes, and inflammation. Treg-cell proliferation is controlled by antigen-presenting DCs. On the other hand, Treg cells suppress the function of DCs by restraining DC maturation. Therefore, the interaction between DCs and Treg cells, DC-Treg crosstalk, could contribute to controlling health and disease. We recently found that unique DC-Treg crosstalk plays a role in several conditions. First, Treg cells are expanded in ultraviolet B (UVB)-exposed skin by interacting with DCs, and the UVB-expanded Treg cells have a healing function. Second, manipulating DC-Treg crosstalk can induce effective acquired immune responses against severe acute respiratory syndrome coronavirus 2 antigens without adjuvants. Third, Treg cells with a special feature interact with DCs in the tumor microenvironment of human head and neck cancer, which may contribute to the prognosis. Understanding the underlying mechanisms of DC-Treg crosstalk may provide a novel strategy to control health and disease.

Novel UV-B Phototherapy With a Light-Emitting Diode Device Prevents Atherosclerosis by Augmenting Regulatory T-Cell Responses in Mice

BACKGROUND

Ultraviolet B (UV-B) irradiation is an effective treatment for human cutaneous disorders and was shown to reduce experimental atherosclerosis by attenuating immunoinflammatory responses. The aim of this study was to clarify the effect of specific wavelengths of UV-B on atherosclerosis and the underlying mechanisms focusing on immunoinflammatory responses.

METHODS AND RESULTS

Based on light-emitting diode technology, we developed novel devices that can emit 282 nm UV-B, which we do not receive from natural sunlight, 301 nm UV-B, and clinically available 312 nm UV-B. We irradiated 6-week-old male atherosclerosis-prone Apoe-/- (apolipoprotein E-deficient) mice with specific wavelengths of UV-B and evaluated atherosclerosis and immunoinflammatory responses by performing histological analysis, flow cytometry, biochemical assays, and liquid chromatography/mass spectrometry-based lipidomics. Irradiation of 282 nm UV-B but not 301 or 312 nm UV-B significantly reduced the development of aortic root atherosclerotic plaques and plaque inflammation. This atheroprotection was associated with specifically augmented immune responses of anti-inflammatory CD4+ Foxp3 (forkhead box P3)+ regulatory T cells in lymphoid tissues, whereas responses of other immune cells were not substantially affected. Analysis of various lipid mediators revealed that 282 nm UV-B markedly increased the ratio of proresolving to proinflammatory lipid mediators in the skin.

CONCLUSIONS

We demonstrated that 282 nm UV-B irradiation effectively reduces aortic inflammation and the development of atherosclerosis by systemically augmenting regulatory T-cell responses and modulating the balance between proresolving and proinflammatory lipid mediators in the skin. Our findings indicate that a novel 282 nm UV-B phototherapy could be an attractive approach to treat atherosclerosis.

The roles of T cells in psoriasis

Psoriasis is a recurring inflammatory skin condition characterized by scaly, red patches on the skin. It affects approximately 3% of the US population and is associated with histological changes such as epidermal hyperplasia, increased blood vessel proliferation, and infiltration of leukocytes into the skin's dermis. T cells, which are classified into various subtypes, have been found to play significant roles in immune-mediated diseases, particularly psoriasis. This paper provides a review of the different T lymphocyte subtypes and their functions in psoriasis, as well as an overview of targeted therapies for treating psoriasis.

The optimal use of tildrakizumab in the elderly via improvement of Treg function and its preventive effect of psoriatic arthritis

Introduction

As a form of precision medicine, this study aimed to investigate the specific patient population that would derive the greatest benefit from tildrakizumab, as well as the mechanism of action and efficacy of tildrakizumab in reducing the occurrence of psoriatic arthritis (PsA).

Methods

To achieve this, a multi-center, prospective cohort study was conducted, involving a population of 246 psoriasis patients who had not received any systemic therapy or topical finger therapy between January 2020 and April 2023. Two independent clinicians, who were blinded to the study, analyzed nailfold capillary (NFC) abnormalities, such as nailfold bleeding (NFB) and enlarged capillaries, as well as the incidence of new PsA. Additionally, the factors that determined the response of psoriasis after seven months of tildrakizumab treatment were examined. The study also examined the quantity and role of regulatory T cells (Tregs) and T helper 17 cells both pre- and post-treatment.

Results

The severity of psoriasis, as measured by the Psoriasis Area and Severity Index (PASI), was found to be more pronounced in the tildrakizumab group (n=20) in comparison to the topical group (n=226). At 7 months after tildrakizumab treatment, multivariate analysis showed that those 65 years and older had a significantly better response to treatment in those achieved PASI clear or PASI 2 or less (Likelihood ratio (LR) 16.15, p<0.0001; LR 6. 16, p=0.01). Tildrakizumab improved the number and function of Tregs, which had been reduced by aging. Tildrakizumab demonstrated significant efficacy in improving various pathological factors associated with PsA. These factors include the reduction of NFB, enlargement of capillaries, and inhibition of PsA progression. The hazard ratio for progression to PsA was found to be 0.06 (95% confidence interval: 0.0007-0.46, p=0.007), indicating a substantial reduction in the risk of developing PsA.

Discussion

Tildrakizumab's effectiveness in improving skin lesions can be attributed to its ability to enhance the number and function of Tregs, which are known to decline with age. Furthermore, the drug's positive impact on NFB activity and capillary enlargement, both of which are recognized as risk factors for PsA, further contribute to its inhibitory effect on PsA progression.

Water-responsive gel extends drug retention and facilitates skin penetration for curcumin topical delivery against psoriasis

Psoriasis is a chronic inflammatory skin disease characterized by erythema, scaling, and skin thickening. Topical drug application is recommended as the first-line treatment. Many formulation strategies have been developed and explored for enhanced topical psoriasis treatment. However, these preparations usually have low viscosity and limited retention on the skin surface, resulting in low drug delivery efficiency and poor patient satisfaction. In this study, we developed the first water-responsive gel (WRG), which has a distinct water-triggered liquid-to-gel phase transition property. Specifically, WRG was kept in a solution state in the absence of water, and the addition of water induced an immediate phase transition and resulted in a high viscosity gel. Curcumin was used as a model drug to investigate the potential of WRG in topical drug delivery against psoriasis. In vitro and in vivo data showed that WRG formulation could not only extend skin retention but also facilitate the drug permeating across the skin. In a mouse model of psoriasis, curcumin loaded WRG (CUR-WRG) effectively ameliorated the symptoms of psoriasis and exerted a potent anti-psoriasis effect by extending drug retention and facilitating drug penetration. Further mechanism study demonstrated that the anti-hyperplasia, anti-inflammation, anti-angiogenesis, anti-oxidation, and immunomodulation properties of curcumin were amplified by enhanced topical drug delivery efficiency. Notably, neglectable local or systemic toxicity was observed for CUR-WRG application. This study suggests that WRG is a promising formulation for topically psoriasis treatment.

Deregulated phenotype of autoreactive Th17 and Treg clone cells in pemphigus vulgaris after in-vitro treatment with desmoglein antigen (Dsg-3)

The loss of balance between regulatory T (Treg) and T helper 17 (Th17) causes loss of tolerance against desmoglein (Dsg)-3 leading to pemphigus vulgaris (PV), an autoimmune bullous skin disorder associated with autoantibodies against Dsg-3. We aimed to elucidate the complex relationship of Th17 and Treg cells, their molecules, and the underlying mechanism in the development of PV disease. Using cytokine secretion assays, Th17 and Treg cells were sorted by FACS Aria-III within Dsg-3-responsive PBMC population and homogeneous T cell clones were generated in-vitro. Different cell surface molecules like CD25, GITR, CD122, CD152, CD45RO, IL-23R, STAT3, STAT5, CD127, HLA-DR, CCR4, CCR5, CCR6 and CCR7 were studied. The functional response of Th17 and Treg cells were elucidated by measuring the levels of various cytokines released by IL-10 and IL-17 T cells. The mRNA expression of transcription factors (FoxP3 and RORγt) was also analyzed. IL-17 secreting (Th17) cells with phenotype CD4⁺IL-17⁺ were greatly increased and IL-10 secreting (Treg) cells with phenotype CD4⁺IL-10⁺ were reduced in PV cases than healthy controls. The qPCR analysis showing high expression of retinoic acid receptor-related orphan receptor gamma (RORγt) mRNA in comparison to forkhead box P3 (FoxP3) mRNA confirmed the development of pro-inflammatory Th17 response in PV. Further, the cytokine profile of pro-inflammatory and anti-inflammatory cytokines suggested defective suppressive functions in Treg cells with high inflammatory response. Our findings indicate that autoantigen Dsg-3 specifically allows the proliferation of IL-17 secreting T cells though has a negative effect on IL-10 secreting T cells leading to dysregulation of immunity in PV patients. This antagonistic relationship between Dsg-3-specific Th17 and Treg cells may be critical for the onset and persistence of inflammation in PV cases.

Autoreactive T-Cells in Psoriasis: Are They Spoiled Tregs and Can Therapies Restore Their Functions?

Psoriasis is a chronic inflammatory skin disease, which affects 2-4% of the population worldwide. T-cell derived factors such as Th17 and Th1 cytokines or cytokines such as IL-23, which favors Th17-expansion/differentiation, dominate in the disease. Therapies targeting these factors have been developed over the years. An autoimmune component is present, as autoreactive T-cells specific for keratins, the antimicrobial peptide LL37 and ADAMTSL5 have been described. Both autoreactive CD4 and CD8 T-cells exist, produce pathogenic cytokines, and correlate with disease activity. Along with the assumption that psoriasis is a T-cell-driven disease, Tregs have been studied extensively over the years, both in the skin and in circulation. This narrative review resumes the main findings about Tregs in psoriasis. We discuss how Tregs increase in psoriasis but are impaired in their regulatory/suppressive function. We debate the possibility that Tregs convert into T-effector cells under inflammatory conditions; for instance, they may turn into Th17-cells. We put particular emphasis on therapies that seem to counteract this conversion. We have enriched this review with an experimental section analyzing T-cells specific for the autoantigen LL37 in a healthy subject, suggesting that a shared specificity may exist between Tregs and autoreactive responder T-cells. This suggests that successful psoriasis treatments may, among other effects, restore Tregs numbers and functions.

Short-term effects of air pollutants on outpatients with psoriasis in a Chinese city with a subtropical monsoon climate

Introduction

Psoriasis is a common skin disease that seriously affects patients' quality of life. The association of air pollutants with psoriasis, and the extent of their effects remains unclear.

Methods

Based on a distributed lag non-linear model, this study explored the short-term effects of air pollutants on outpatients with psoriasis in Hefei, China, between 2015 and 2019 by analyzing the exposure-lag-response relationship, after controlling for confounding influences such as meteorological factors, long-term trends, day of the week, and holidays. Stratified analyses were performed for patients of different ages and genders.

Results

The maximum relative risks of psoriasis outpatients' exposure to SO₂, NO₂, and O₃ were 1.023 (95% confidence intervals (CI): 1.004-1.043), 1.170 (95% CI: 1.046-1.307), and 1.059 (95% CI: 1.030-1.090), respectively. An increase of 10 μg/m ³ of NO₂ was associated with a 2.1% (95% CI: 0.7-3.5%) increase in outpatients with psoriasis, and a decrease of 10 μg/m ³ of O₃ was associated with an 0.8% (95% CI: 0.4-1.2%) increase in outpatients with psoriasis. Stratified analyses showed that male subjects were more sensitive to a change in meteorological factors, while female subjects and outpatients with psoriasis aged 0-17 years old were more sensitive to a change in air pollutants.

Discussion

Short-term air pollutant exposures were associated with outpatients having psoriasis, suggesting that patients and high-risk people with psoriasis should reduce their time spent outside and improve their skin protection gear when air quality is poor.

Efficacy and safety of apremilast and phototherapy versus phototherapy only in psoriasis vulgaris

Phototherapy and apremilast (oral phosphodiesterase-4 inhibitor) are well-known in the treatment of moderate to severe psoriasis vulgaris. However, current evidence on the efficacy and safety of their combination is not sufficient. This multicenter, randomized controlled study compared the efficacy and safety between phototherapy as monotherapy and phototherapy and apremilast as combination therapy in patients with psoriasis vulgaris. Patients with moderate to severe psoriasis vulgaris were assigned to combination (n = 29) and monotherapy (n = 13) groups. All patients underwent an 8-week phototherapy regimen comprising irradiation with narrowband UV-B. The patients in the combination group were also administered 10 mg to 60 mg of oral apremilast. We evaluated the improvement percentage based on the Psoriasis Area and Severity Index (PASI) score from baseline to week 8. Additionally, we evaluated the percentage of patients who achieved ≥75% improvement; changes in body surface area (BSA) and scores of EuroQol 5-dimensions 5-level, Dermatology Life Quality Index, and visual analog scale for pruritis from baseline to 4 and 8 weeks; and adverse events. Compared with the monotherapy group, the combination group had significantly lower PASI scores at 4 and 8 weeks and more patients who achieved a PASI score improvement of ≥75% at 8 weeks. Both groups exhibited a significant decrease in BSA; at 8 weeks, no significant difference was observed between the two groups, although the combination group tended toward a greater reduction in BSA. The intergroup differences in the changes at the three time points were not significant. Adverse events were more frequent in the combination group than in the monotherapy group. Our findings suggest that an 8-week combined apremilast and phototherapy regimen may not be adequate in patients for improvements in their subjective assessment of psoriasis, and longer treatment periods may be necessary.

The Dopamine Gene Receptors (DRD1-5) Expression Alteration in Psoriasis Patients

BACKGROUND

Psoriasis is a chronic inflammatory autoimmune disease that is considered linked to genetic and environmental factors such as stress. Since the neurotransmitter dopamine has a close association with stress configuration, it can be a candidate for relieving psoriasis representation. In addition to the CNS, immune cells can play a decisive role in regulating immune functions through dopamine synthesis and the expression of its receptors. Altered response of immune cells to dopamine as well as a distorted expression of dopamine receptors (DRs) in immune cells have been reported in some chronic inflammatory conditions.

OBJECTIVE

This study aims the evaluation of dopamine receptor (DR1-DR5) gene expression in mononuclear blood cells of psoriatic patients in comparison with normal individuals.

METHODS

We isolated peripheral mononuclear cells (PBMCs) from blood samples followed by total RNA extraction, cDNA synthesis, and real-time PCR using specific primer pairs.

RESULTS

We found that all types of DRs are expressed in the PBMCs of normal and psoriatic individuals. We also concluded that compared to controls, DR2 and DR4 were overexpressed in psoriasis patients while DR3 was low-expressed.

CONCLUSION

Increased expression of DR2 and DR4 along with decreased expression of DR3 in PBMCs of psoriasis patients not only provide new insight into the pathogenesis of psoriasis but may also be effective in designing future therapeutic strategies attributable to psoriasis.

The peripheral blood regulatory T-cells analysis as a criterion for assessing the therapy efficacy and a prognostic marker for the duration of remission of psoriasis

Background. The recently discovered regulatory T-cells CD4+CD25+FOXP3+CD127low (Treg-cells) plays an important role in sustaining immune tolerance. These cells demonstrated a significant tremendous potential in suppressing the pathological immune response associated with various autoimmune diseases, including psoriasis vulgaris (VP). Aims. To find the role of Treg-cells in VP pathogenesis and to show the possible use of the Treg-cells analysis for diagnosis, remission duration prediction and measurement of therapeutic effectiveness. Materials and methods. We studied 60 VP patients (35 females and 25 males) aged 1855. The patients were diagnosed with VP at advanced, remedial and retrogressive phases (28, 19 and 13 participants, respectively). The disease severity was assessed with the PASI (Psoriasis Area and Severity Index). The patients were stratified into two groups based on disease duration (less than 20 years, n = 42; over 20 years, n = 28). The study involved 12 VP patients in the advanced stage, whose Treg level was tested prior and after 311 nm UVB course. We followed up the VP patients for two years following the UVB-311 nm phototherapy course to assess the remission duration and the relapse frequency. Results. We found lower levels of Тreg in patients in the study group. Treg peripheral blood levels in VP patients and in HD were 2.84 1.00% and 4.02 0.73%, respectively. The Treg levels were 2.59 0.68%, 2.82 1.55% and 3.68 1.62% at advanced, remedial and retrogressive stages, respectively. The patients with the VP history less than 20 years demonstrated Treg level of 3.42 1.11% and 2.31 0.62% for patients with VP history over 20 years. We found an inverse correlation between the Treg subpopulation CD4+CD25+FOXP3+CD127low and the VP severity level evaluated with PASI (r = 0.39). The UVB-311 nm phototherapy resulted in the significant Treg level increase in 12 patients (2.11 0.61% and 3.43 1.02% prior and after therapy, respectively). Subsequently, we revealed the direct correlation (r = 0.88) between the Treg cell level increase in patients prior and after the phototherapy and the duration of remission in this group of the VP patients. Conclusions. We found decreased in Treg levels in VP patients compared to HD and revealed correlation between Treg-cells level in VP patients and VP phases, duration and the severity of the clinical picture. We demonstrated Treg feasibility as a laboratory indicator of VP therapy treatment with the example of 311 nm UVB and as a predict factor of remission duration.

Recent Advances on the Role and Therapeutic Potential of Regulatory T Cells in Atherosclerosis

Atherosclerotic diseases, including ischemic heart disease and stroke, are a main cause of mortality worldwide. Chronic vascular inflammation via immune dysregulation is critically involved in the pathogenesis of atherosclerosis. Accumulating evidence suggests that regulatory T cells (Tregs), responsible for maintaining immunological tolerance and suppressing excessive immune responses, play an important role in preventing the development and progression of atherosclerosis through the regulation of pathogenic immunoinflammatory responses. Several strategies to prevent and treat atherosclerosis through the promotion of regulatory immune responses have been developed, and could be clinically applied for the treatment of atherosclerotic cardiovascular disease. In this review, we summarize recent advances in our understanding of the protective role of Tregs in atherosclerosis and discuss attractive approaches to treat atherosclerotic disease by augmenting regulatory immune responses.

308-nm Excimer Lamp vs. Combination of 308-nm Excimer Lamp and 10% Liquor Carbonis Detergens in Patients With Scalp Psoriasis: A Randomized, Single-Blinded, Controlled Trial

Background: Scalp psoriasis is usually refractory to treatment. Excimer devices have been proved to be a promising therapeutic option in psoriasis. Greater efficacy of phototherapy can be achieved by concurrent use of coal tar derivatives.

Objective: We aimed to compare efficacy and safety between 308-nm excimer lamp monotherapy and a combination of 308-nm excimer lamp and 10% liquor carbonis detergens in the treatment of scalp psoriasis.

Methods: In this randomized, evaluator-blinded, prospective, comparative study, 30 patients with scalp psoriasis received either 308-nm excimer lamp monotherapy or a combination of 308-nm excimer lamp and 10% liquor carbonis detergens twice per week until complete remission of the scalp or for a total of 30 sessions. Efficacy was evaluated by the improvement of Psoriasis Scalp Severity Index (PSSI) score, itch score, and Scalpdex score.

Results: Both treatments induced significant improvement in PSSI score with greater reduction observed in the combination group. At 30th visit, a 75% reduction in PSSI (PSSI75) was attained by 4 (28.6%) and 9 (69.2%) patients treated with monotherapy and combination therapy, respectively (P < 0.05).

Conclusions: Excimer lamp is well-tolerated in patients with scalp psoriasis and liquor carbonis detergens can be used as a combination therapy to improve the efficacy of excimer lamp.

More Than Effects in Skin: Ultraviolet Radiation-Induced Changes in Immune Cells in Human Blood

Cells of the skin and circulation are in constant two-way communication. Following exposure of humans to sunlight or to phototherapy, there are alterations in the number, phenotype and function of circulating blood cells. In this review, only data obtained from human studies are considered, with changes induced by UV radiation (UVR) exposure described for phagocytic leukocytes and peripheral blood mononuclear cells plus their component T and B cells, natural killer cells and dendritic cells. These immune modulations illustrate the potential of UVR to have therapeutic effects beyond the skin, and that sunlight exposure is an important environmental influence on human health.

pH-Dependent Photoinduced Interconversion of Furocoumaric and Furocoumarinic Acids

Photo-controlled or photo-regulated molecules, especially biologically active and operating in physiological conditions, are in steady demand. Herein, furocoumaric and furocoumarinic acids being (Z/E)-isomers relative to each other were obtained in two stages starting from psoralen: the alkaline solvolysis of psoralen led to furocoumaric acid, which was further Z → E photoisomerized (365 nm) to furocoumarinic acid. The kinetics of Z → E photoisomerization was monitored by HPLC and UV-vis spectrophotometry. Photophysical characteristics in the aqueous phase for both acids, as well as the reversibility of (Z/E) photoisomerization process, were also assessed. Furocoumarinic acid was found to be visibly fluorescent at pH 2.0-12.0, with the maxima of fluorescence emission spectra being pH-dependent. The reverse E → Z photoisomerization predicted by quantum chemistry calculations as energetically favorable for the monoanionic form of furocoumarinic acid was proved in the experiment while being complicated by pyrone ring closure back to psoralen in acidic and neutral conditions. The preparative synthesis of furocoumarinic acid outlined in this work is particularly valuable in view of a wide range of pharmacological effects previously predicted for this compound.

Oral and Topical Vitamin D, Sunshine, and UVB Phototherapy Safely Control Psoriasis in Patients with Normal Pretreatment Serum 25-Hydroxyvitamin D Concentrations: A Literature Review and Discussion of Health Implications

Vitamin D, sunshine and UVB phototherapy were first reported in the early 1900s to control psoriasis, cure rickets and cure tuberculosis (TB). Vitamin D also controlled asthma and rheumatoid arthritis with intakes ranging from 60,000 to 600,000 International Units (IU)/day. In the 1980s, interest in treating psoriasis with vitamin D rekindled. Since 1985 four different oral forms of vitamin D (D2, D3, 1-hydroxyvitaminD3 (1(OH)D3) and 1,25-dihydroxyvitaminD3 (calcitriol)) and several topical formulations have been reported safe and effective treatments for psoriasis-as has UVB phototherapy and sunshine. In this review we show that many pre-treatment serum 25(OH)D concentrations fall within the current range of normal, while many post-treatment concentrations fall outside the upper limit of this normal (100 ng/mL). Yet, psoriasis patients showed significant clinical improvement without complications using these treatments. Current estimates of vitamin D sufficiency appear to underestimate serum 25(OH)D concentrations required for optimal health in psoriasis patients, while concentrations associated with adverse events appear to be much higher than current estimates of safe serum 25(OH)D concentrations. Based on these observations, the therapeutic index for vitamin D needs to be reexamined in the treatment of psoriasis and other diseases strongly linked to vitamin D deficiency, including COVID-19 infections, which may also improve safely with sufficient vitamin D intake or UVB exposure.

Role of regulatory T cells in psoriasis pathogenesis and treatment

Psoriasis is a chronic inflammatory disease with a strong genetic component that can be triggered by environmental factors. Disease pathogenesis is mainly driven by type 1 and type 17 cytokine-producing cells which, in healthy individuals, are modulated by regulatory T cells (Tregs). Tregs play a fundamental role in immune homeostasis and contribute to the prevention of autoimmune disease by suppressing immune responses. In psoriasis, Tregs are impaired in their suppressive function leading to an altered T-helper 17/Treg balance. Although Treg dysfunction in patients with psoriasis is associated with disease exacerbation, it is unknown how they are functionally regulated. In this review, we discuss recent insights into Tregs in the setting of psoriasis with an emphasis on the effect of current treatments on Tregs and how already available therapeutics that modulate Treg frequency or functionality could be exploited for treatment of psoriasis.

A deep dive into UV-based phototherapy: Mechanisms of action and emerging molecular targets in inflammation and cancer

UV-based phototherapy (including psoralen plus UVA (PUVA), UVB and UVA1) has a long, successful history in the management of numerous cutaneous disorders. Photoresponsive diseases are etiologically diverse, but most involve disturbances in local (and occasionally systemic) inflammatory cells and/or abnormalities in keratinocytes that trigger inflammation. UV-based phototherapy works by regulating the inflammatory component and inducing apoptosis of pathogenic cells. This results in a fascinating and complex network of simultaneous events-immediate transcriptional changes in keratinocytes, immune cells, and pigment cells; the emergence of apoptotic bodies; and the trafficking of antigen-presenting cells in skin-that quickly transform the microenvironment of UV-exposed skin. Molecular elements in this system of UV recognition and response include chromophores, metabolic byproducts, innate immune receptors, neurotransmitters and mediators such as chemokines and cytokines, antimicrobial peptides, and platelet activating factor (PAF) and PAF-like molecules that simultaneously shape the immunomodulatory effects of UV and their interplay with the microbiota of the skin and beyond. Phototherapy's key effects-proapoptotic, immunomodulatory, antipruritic, antifibrotic, propigmentary, and pro-prebiotic-promote clinical improvement in various skin diseases such as psoriasis, atopic dermatitis (AD), graft-versus-host disease (GvHD), vitiligo, scleroderma, and cutaneous T-cell lymphoma (CTCL) as well as prevention of polymorphic light eruption (PLE). As understanding of phototherapy improves, new therapies (UV- and non-UV-based) are being developed that will modify regulatory T-cells (Treg), interact with (resident) memory T-cells and /or utilize agonists and antagonists as well as antibodies targeting soluble molecules such as cytokines and chemokines, transcription factors, and a variety of membrane-associated receptors.

Effect of methotrexate treatment on the expression of epidermal-fatty acid-binding protein (E-FABP) and apolipoproteins in patients with psoriasis

Introduction

Epidermal-fatty acid-binding protein (E-FABP) is a marker of transiently amplifying cells which are formed from stem cells in epidermis. Their role is an uptake of fatty acids and metabolism. Psoriatic keratinocytes overexpress E-FABPs, which leads to acanthosis and may explain the lipid’s disturbances in psoriasis.

Aim

Assessment of FABP and apolipoprotein expression in patients treated with methotrexate (MTX).

Material and methods

FABP expression in the lesional and perilesional psoriatic skin from 11 male patients compared to 5 healthy skin samples were evaluated by immunohistochemistry. FABP, apolipoprotein A1 (ApoA1) and B (ApoB) serum levels were assessed by ELISA. These parameters were evaluated before and after treatment with subcutaneous MTX (15 mg/wk for 12 weeks).

Results

Expression of E-FABP was lower in the control group than in the lesional and perilesional psoriatic skin, before and after treatment. After treatment the expression decreased in the lesional and perilesional skin. Serum E-FABP was higher in the control group (482.855 ±240.550 pg/ml) compared to patients, but not statistically significantly. After MTX treatment, a statistically significant reduction was observed in psoriatic patients. ApoA1 levels did not differ in the control and patients groups, both before and after treatment. In contrast, ApoB levels did not differ statistically between the control group (1447.126 ±311.11 ng/ml) and patients before treatment, while they were the lowest after treatment (1081.67 ±117.83 ng/ml vs. 808.306 ±103.72 ng/ml; p < 0.01).

Conclusions

Our study confirms the beneficial effect of MTX, not only as an anti-proliferative effect, but also reducing the cardiovascular risk by decreasing atherogenic ApoB.

How It Works: The Immunology Underlying Phototherapy

Phototherapeutic modalities induce apoptosis of keratinocytes and immune cells, impact cytokine production, downregulate the IL-23/Th17 axis, and induce regulatory T cells. As in anti-IL-17 or anti-IL-23 antibody treatment, the dual action of phototherapy on skin and the immune system is likely responsible for sustained resolution of lesions in diseases such as psoriasis. In cutaneous T cell lymphoma, phototherapy may function by causing tumor cell apoptosis and eliminating the neoplastic and inflammatory infiltrate. Further research on phototherapeutic mechanisms will help advance, optimize, and refine dermatologic treatments and may open up novel avenues for treatment strategies in dermatology and beyond.

Pathogenesis of psoriasis in the "omic" era. Part I. Epidemiology, clinical manifestation, immunological and neuroendocrine disturbances

Psoriasis is a common, chronic, inflammatory, immune-mediated skin disease affecting about 2% of the world's population. According to current knowledge, psoriasis is a complex disease that involves various genes and environmental factors, such as stress, injuries, infections and certain medications. The chronic inflammation of psoriasis lesions develops upon epidermal infiltration, activation, and expansion of type 1 and type 17 Th cells. Despite the enormous progress in understanding the mechanisms that cause psoriasis, the target cells and antigens that drive pathogenic T cell responses in psoriatic lesions are still unproven and the autoimmune basis of psoriasis still remains hypothetical. However, since the identification of the Th17 cell subset, the IL-23/Th17 immune axis has been considered a key driver of psoriatic inflammation, which has led to the development of biologic agents that target crucial elements of this pathway. Here we present the current understanding of various aspects in psoriasis pathogenesis.

Kaempferol attenuates imiquimod-induced psoriatic skin inflammation in a mouse model

Psoriasis is an immune-mediated inflammatory skin disease that mainly affects the skin barrier. Treatment for psoriasis mainly includes conventional immunosuppressive drugs. However, long-term treatment with global immunosuppressive agents may cause a variety of side effects, including nephrotoxicity and infections. Kaempferol, a natural flavonol present in various plants, is known to possess potent anti-inflammatory, anti-oxidant and anti-cancerous properties. However, it is unknown whether kaempferol is also anti-psoriatic. Here we established an imiquimod (IMQ)-induced psoriatic mouse model to explore the potential therapeutic effects of kaempferol on psoriatic skin lesions and inflammation. In this study, we demonstrated that treatment with kaempferol protected mice from developing psoriasis-like skin lesions induced by topical administration of IMQ. Kaempferol reduced CD3+ T cell infiltration and gene expression of major proinflammatory cytokines, including interleukin (IL)-6, IL-17A and tumor necrosis factor (TNF)-α, in the psoriatic skin lesion. It also down-regulated proinflammatory nuclear factor kappa B (NF-κB) signaling in the skin. The therapeutic effects were associated with a significant increase in CD4+ forkhead box protein 3 (FoxP3)+ regulatory T cell (Treg ) frequency in the spleen and lymph nodes as well as FoxP3-positive staining in the skin lesion. Conversely, depletion of CD4+ CD25+ Tregs reversed the therapeutic effects of kaempferol on the skin lesion. Kaempferol also lowered the percentage of IL-17A+ CD4+ T cells in the spleen and lymph nodes of IMQ-induced psoriatic mice. Finally, kaempferol suppressed the proliferation of T cells in vitro and their mTOR signaling. Thus, our findings suggest that kaempferol may be a therapeutic drug for treating human psoriasis in the near future.

Risk of End-Stage Renal Disease in Psoriatic Patients: Real-World Data from a Nationwide Population-Based Cohort Study

Psoriasis is a chronic inflammatory skin disorder mediated by the T-cell–related immune response. Psoriatic patients may have a variety of comorbidities, but their risk of end-stage renal disease (ESRD), particularly according to the subtype of psoriasis, is unclear. We investigated the risk of ESRD in patients with psoriasis according to the subtype of psoriasis and history of systemic therapy for psoriasis. A total of 2,121,228 adults (1,590,921 in the control group and 530,307 in the psoriasis group) were enrolled in this nationwide population-based cohort study until 2015. During follow-up, 1,434 of the subjects in the psoriasis group developed ESRD. After adjusting for confounding factors, psoriasis was associated with the risk of ESRD (hazard ratio (HR) 1.58, 95% confidence interval [95% CI] 1.47–1.68). The psoriatic arthritis group (HR 7.60, 95% CI 1.90–30.41) had a higher risk of ESRD than the control group. Interestingly, no such association was detected in the systemically treated group (HR 1.07, 95% CI 0.80–1.41). Moreover, the acitretin-treated group had a lower risk of ESRD (HR 0.658, 95% CI, 0.494–0.875) than the non-systemically treated group. In conclusion, the risk of developing ESRD in patients with psoriasis differed according to the type of treatment and the presence of arthritis.

Anti-IL-17A and IL-23p19 antibodies but not anti-TNFα antibody induce expansion of regulatory T cells and restoration of their suppressive function in imiquimod-induced psoriasiform dermatitis

BACKGROUND

Psoriasis is a chronic inflammatory skin disease. Anti-TNFα, IL-17A and IL-23p19 antibodies are effective for psoriasis. However, the contribution of regulatory T cells (Treg) in their effectiveness remains to be elucidated.

OBJECTIVE

We investigated the effects of TNFα, IL-17A and IL-23p19 inhibition on Tregs in imiquimod-induced psoriasiform dermatitis.

METHODS

Psoriasiform dermatitis was induced by imiquimod application on murine shaved back skin for six days. Mice were treated with anti-TNFα, IL-17A or IL-23p19 monoclonal antibodies every other day from one day before imiquimod application.

RESULTS

Administration of anti-TNFα, IL-17A or IL-23p19 antibodies improved the clinical score and downregulated Th17-related cytokines and chemokines, while IL-23p19 antibodies upregulated IL-10 mRNA expression. Anti-IL-17A or IL-23p19 antibody-treated imiquimod-applied mice showed a significant increase in the number of Foxp3⁺ IL-10⁺ Tregs. Recipient mice adoptively transferred with Tregs derived from donor mice treated with antibodies demonstrated clinical and pathological improvement in imiquimod-induced psoriasiform dermatitis. Anti-IL-17A or IL-23p19 antibody-induced Tregs significantly increased the number of Foxp3⁺ cells and IL-10 expression in imiquimod-induced psoriasiform dermatitis in recipient mice but anti-TNFα antibody-induced Tregs did not.

CONCLUSION

Anti-IL-17A or IL-23p19 antibody inhibits the IL-17/IL-23 signaling pathway, and induces expansion of Tregs and their suppressive capacity in imiquimod-induced psoriasiform dermatitis.

Evaluation of selected mechanisms of immune tolerance in psoriasis

INTRODUCTION

Psoriasis is an autoimmune disease with an excessively aberration of the Th17/Treg balance and deficiency of anti-inflammatory cytokines.

AIM

Evaluation of Treg markers expression in the lesional and perilesional psoriatic skin and serum anti-inflammatory cytokines in male psoriatic patients compared to healthy men.

MATERIAL AND METHODS

Treg markers (FoxP3+, CD4, CTLA-4, CD25/IL-2R, CD39/ENTPD1, IL-7R/CD127, CD3) and tissue expression of protective cytokines (IL-10, IL-35, TGF-β) in the lesional and perilesional psoriatic skin from 33 male patients compared to 6 healthy skin samples were evaluated by immunohistochemistry. ELISA was used to assess serum IL-10, IL-35 and TGF-β levels.

RESULTS

The serum levels of IL-35, IL-10 and TGF-β1 were higher in psoriatic patients than in controls but without any statistically significant relationship with PASI. The expressions of IL-35, CD4, IL-10, TGF-β1, CD3, FOXP3 and CD25/IL-2R were varied in different experimental groups (p < 0.05). The level of IL-35 was the lowest in psoriatic lesions (p < 0.05) compared to perilesional skin and to controls. CD4, IL-10 and TGF-β1 expressions were higher (p < 0.05) in perilesional skin than in lesions. TGF-β1 expression was decreased in psoriatic lesions compared to controls (p < 0.05). CD25/IL2R expression was increased in healthy skin compared to psoriatic skin (p < 0.05). FOXP3 expression was elevated in psoriatic skin compared to healthy and perilesional one. There was no difference between experimental groups in CTLA-4, IL7R/CD127 and CD39/ENTPD1 expression.

CONCLUSIONS

The differences between the levels of protective cytokines and expression of Treg markers might explain the inflammation development in psoriasis.

Dead Sea climatotherapy versus topical steroid treatment for atopic dermatitis children: long-term follow-up study

The aim of this study was to compare long-term results of 4 weeks Dead Sea climatotherapy at the Deutsches Medizinisches Zentrum, Israel to those obtained by classical topical treatment for moderate-to-severe atopic dermatitis. Seventy-two children from the Czech Republic were divided into three groups of 24 and treated during three periods (March 2014, October 2014 and March 2015) with gradually increasing sun exposure during 28 consecutive days. Forty-four children were treated with steroid creams at the Department of Dermatovenereology, Third Faculty of Medicine, Charles University and University Hospital of Kralovske Vinohrady, Prague, Czech Republic. The primary outcome was the change in the SCORing Atopic Dermatitis (SCORAD) index, recorded after 1 month of treatment (immediately after DSC) and 3, 6, 9, 12, and 18 months later in Prague. The mean SCORAD improvement was 87.5 ± 13.4% after 4 weeks at the Dead Sea and 86.1 ± 11.3% after 1 month of treatment with steroid creams in the Czech Republic. All 44 patients treated in Prague participated in this 18-month follow-up study, whereas only 47 patients (65.3%) after DSC treatment. Good clinical results were maintained in both groups and mean SCORAD values were stable and low, around 5.

Human health in relation to exposure to solar ultraviolet radiation under changing stratospheric ozone and climate

The Montreal Protocol has limited increases in the UV-B (280-315 nm) radiation reaching the Earth's surface as a result of depletion of stratospheric ozone. Nevertheless, the incidence of skin cancers continues to increase in most light-skinned populations, probably due mainly to risky sun exposure behaviour. In locations with strong sun protection programs of long duration, incidence is now reducing in younger age groups. Changes in the epidemiology of UV-induced eye diseases are less clear, due to a lack of data. Exposure to UV radiation plays a role in the development of cataracts, pterygium and possibly age-related macular degeneration; these are major causes of visual impairment world-wide. Photodermatoses and phototoxic reactions to drugs are not uncommon; management of the latter includes recognition of the risks by the prescribing physician. Exposure to UV radiation has benefits for health through the production of vitamin D in the skin and modulation of immune function. The latter has benefits for skin diseases such as psoriasis and possibly for systemic autoimmune diseases such as multiple sclerosis. The health risks of sun exposure can be mitigated through appropriate sun protection, such as clothing with both good UV-blocking characteristics and adequate skin coverage, sunglasses, shade, and sunscreen. New sunscreen preparations provide protection against a broader spectrum of solar radiation, but it is not clear that this has benefits for health. Gaps in knowledge make it difficult to derive evidence-based sun protection advice that balances the risks and benefits of sun exposure.

Regulatory cells in the skin: Pathophysiologic role and potential targets for anti-inflammatory therapies

Inflammation is a fundamental defense mechanism to protect the body from danger, which becomes potentially harmful if it turns chronic. Therapeutic strategies aimed at specifically blocking proinflammatory signals, particularly cytokines, such as IL-4, IL-6, IL-13, IL-17A, or TNF-α, have substantially improved our ability to effectively and safely treat chronic inflammatory diseases. Much less effort has been made to better understand the role of potential anti-inflammatory mechanisms. Here we summarize the current understanding of regulatory cell populations in the context of chronic inflammation, namely macrophages, Langerhans cells, myeloid-derived suppressor cells, and regulatory T and B lymphocytes. Emphasis is given to the skin because many different immune-related diseases occur in the skin. Development, phenotype, function, and evidence for their role in animal models of inflammation, as well as in the corresponding human diseases, are described. Finally, the feasibility of using regulatory cells as targets for potentially disease-modifying therapeutic strategies is discussed.

Deviations in Peripheral Blood Cell Populations are Associated with the Stage of Primary Biliary Cholangitis and Presence of Itching

To evaluate the role of Th17, Treg cells, activated T CD3+ and B CD19+ lymphocytes in primary biliary cholangitis (PBC) patients. 40 female patients with PBC and 20 healthy donors were enrolled in this study. The percentages and absolute counts of Th17, Treg, activated T CD3+, B CD19+, NK, NKT-like lymphocytes were measured by flow cytometry. Our research revealed significantly lower frequencies and absolute counts of CD4+CD25+FOXP3+ Treg cells (p < 0.0001), higher percentages and absolute counts of Th17 cells (IL-17A+CD3+CD4+; p < 0.0001 and p = 0.009, respectively), CD3-/CD16+CD56+ NK cells (p < 0.0001 and p = 0.039, respectively), CD3+/CD16+CD56+ NKT-like cells (p < 0.0001 and p = 0.048, respectively). There were also higher percentages and numbers of B CD19+ lymphocytes (p = 0.002 and p = 0.001, respectively) and higher percentages and absolute counts of activated B CD19+CD25+ cells (p = 0.007 and p = 0.002, respectively). Moreover, we observed a statistically significant correlation between the presence of itching and particular peripheral blood subpopulations in PBC patients. Absolute counts of both CD4+CD3+ cells (p = 0.0119) and CD3+CD25+ cells (p = 0.0329) were lower in patients with pruritus. A similar dependency was noted in reference to percentages of NKT-like cells (CD3+/CD16+CD56+; p = 0.0359) and (CD3+) T lymphocytes (p = 0.0302). Th17 and Treg cells are involved in the course of PBC. There is also the association between the pruritus and peripheral blood subpopulations.

T Regulatory Cell Subpopulations Associated with Recent Ultraviolet Radiation Exposure in a Skin Cancer Screening Cohort

UV radiation (UVR) causing DNA damage is a well-documented risk factor for nonmelanoma skin cancer. Although poorly understood, UVR may also indirectly contribute to carcinogenesis by promoting immune evasion. To our knowledge, we report the first epidemiological study designed to investigate the association between quantitative measures of UVR, obtained using a spectrophotometer, and circulating T regulatory (Treg) cells. In addition to total Treg cells, the proportion of functionally distinct Treg cell subsets defined by CD45RA and CD27 phenotypic markers, graded expression of FOXP3 and CD25, and those expressing cutaneous lymphocyte-associated Ag and the chemokine receptor CCR4 were enumerated in 350 individuals undergoing routine skin cancer screening exams and determined not to have prevalent skin cancer. No associations were identified for UVR exposure or the overall proportion of circulating Treg cells; however, Treg cell subpopulations with an activation-associated phenotype, CD45RA^-/CD27^-, and those expressing cutaneous homing receptors were significantly positively associated with UVR. These subpopulations of Treg cells also differed by age, sex, and race. After stratification by natural skin tone, and adjusting for age and sex, we found that spectrophotometer-based measures of UVR exposure, but not self-reported measures of past sun exposure, were positively correlated with the highest levels of these Treg cell subpopulations, particularly among lighter-skinned individuals. Findings from this large epidemiologic study highlight the diversity of human Treg cell subpopulations associated with UVR, thus raising questions about the specific coordinated expression of CD45RA, CD27, CCR4, and cutaneous lymphocyte-associated Ag on Treg cells and the possibility that UVR contributes to nonmelanoma skin cancer carcinogenesis through Treg cell-mediated immune evasion.

Effect of methotrexate monotherapy on T-cell subsets in the peripheral circulation in psoriasis

BACKGROUND

Psoriasis is a T-helper (Th)1/Th17-mediated chronic inflammatory disease. There is an increased population of Th cells in skin lesions and peripheral circulation of patients with psoriasis. Systemic methotrexate (MTX) is an effective treatment for moderate to severe psoriasis; however, its effect on different T-cell subsets is not yet clear.

AIM

To study the effect of MTX monotherapy on the psoriatic T-cell profile in the peripheral circulation of patients with psoriasis.

METHODS

This was a follow-up study involving 50 patients with moderate to severe psoriasis treated with systemic MTX for 12 weeks. Blood samples (5 mL) were collected from participants, from which PBMCs were isolated, and T-cell phenotyping was performed by flow cytometry.

RESULTS

Following 12 weeks of MTX treatment, there was an increase in the percentages of Th2/Treg cells, and a relative decrease in the percentages of Th1/Th17 cells, along with a significant reduction in the median Psoriasis Area and Severity Index (PASI).

CONCLUSION

MTX helps in the restoration of the immune balance by decreasing the numbers of Th1 and Th17 cells and increasing the numbers of Th2 and Treg cells, thus resulting in a significant reduction in disease severity. MTX converts a proinflammatory T-cell phenotype to a protective anti-inflammatory phenotype, thus significantly suppressing the inflammation in psoriasis.

From Early Immunomodulatory Triggers to Immunosuppressive Outcome: Therapeutic Implications of the Complex Interplay Between the Wavebands of Sunlight and the Skin

Phototherapy is an efficient treatment for many cutaneous diseases that involve the activation of inflammatory pathways or the overgrowth of cells with aberrant phenotype. In this review, we discuss recent advances in photoimmunology, focusing on the effects of UV-based therapies currently used in dermatology. We describe the molecular responses to the main forms of photo(chemo)therapy such as UVB, UVA-1, and PUVA that include the triggering of apoptotic or immunosuppressive pathways and help to clear diseased skin. The early molecular response to UV involves DNA photoproducts, the isomerization of urocanic acid, the secretion of biophospholipids such as platelet activating factor (PAF), the activation of aryl hydrocarbon receptor and inflammasome, and vitamin D synthesis. The simultaneous and complex interaction of these events regulates the activity of the immune system both locally and systemically, resulting in apoptosis of neoplastic and/or benign cells, reduction of cellular infiltrate, and regulation of cytokines and chemokines. Regulatory T-cells and Langerhans cells, among other skin-resident cellular populations, are deeply affected by UV exposure and are therefore important players in the mechanisms of immunomodulation and the therapeutic value of UV in all its forms. We weigh the contribution of these cells to the therapeutic application of UV and how they may participate in transferring the direct impact of UV on the skin into local and systemic immunomodulation. Moreover, we review the therapeutic mechanisms revealed by clinical and laboratory animal investigations in the most common cutaneous diseases treated with phototherapy such as psoriasis, atopic dermatitis, vitiligo, and cutaneous T-cell lymphoma. Better understanding of phototherapeutic mechanisms in these diseases will help advance treatment in general and make future therapeutic strategies more precise, targeted, personalized, safe, and efficient.

Exposure to Ultraviolet Radiation in the Modulation of Human Diseases

This review focuses primarily on the beneficial effects for human health of exposure to ultraviolet radiation (UVR). UVR stimulates anti-inflammatory and immunosuppressive pathways in skin that modulate psoriasis, atopic dermatitis, and vitiligo; suppresses cutaneous lesions of graft-versus-host disease; and regulates some infection and vaccination outcomes. While polymorphic light eruption and the cutaneous photosensitivity of systemic lupus erythematosus are triggered by UVR, polymorphic light eruption also frequently benefits from UVR-induced immunomodulation. For systemic diseases such as multiple sclerosis, type 1 diabetes, asthma, schizophrenia, autism, and cardiovascular disease, any positive consequences of UVR exposure are more speculative, but could occur through the actions of UVR-induced regulatory cells and mediators, including 1,25-dihydroxy vitamin D₃, interleukin-10, and nitric oxide. Reduced UVR exposure is a risk factor for the development of several inflammatory, allergic, and autoimmune conditions, including diseases initiated in early life. This suggests that UVR-induced molecules can regulate cell maturation in developing organs.

ASTHMA - comparing the impact of vitamin D versus UVR on clinical and immune parameters

The incidence of asthma has increased markedly since the 1960s and is currently estimated to affect more than 300 million individuals worldwide. A number of environmental factors are implicated in asthma pathogenesis, one of which is vitamin D. Vitamin D deficiency is a global health concern and has increased in parallel with asthma incidence. Epidemiological studies report associations between low vitamin D status, assessed as circulating levels of 25-hydroxyvitamin D, with asthma incidence, severity, exacerbations and responses to treatment. This has led to clinical studies to test whether increasing the levels of vitamin D improves asthma management. Despite being highly variable in dosing regimens, design and outcomes, meta-analyses suggest overall positive outcomes with respect to reduced asthma exacerbations and steroid requirements. The primary mechanism for increasing vitamin D levels in the body is through exposure of the skin to the ultraviolet B (UVB) component of ultraviolet radiation (UVR), most commonly from sun exposure. However, only a limited number of studies investigating the impact of UVR on the asthmatic response have been performed; these generally report on the impact of latitude as a surrogate of sun exposure, or address this in animal models. To the best of our knowledge no comprehensive trials to assess the impact of UVB radiation on asthma outcomes have been performed. Within this review we discuss observational and clinical studies in this field, and innate and adaptive immune mechanisms through which UVR and vitamin D may impact respiratory health, and asthma. We highlight the heterogeneity of asthmatic disease, which is likely to impact upon the efficacy of interventional studies, and briefly overview more recent findings relating to the impact of vitamin D/UVR on the development of asthma.

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.

Notch1 Signaling Regulates the Th17/Treg Immune Imbalance in Patients with Psoriasis Vulgaris

Purpose

To evaluate the regulating effect of Notch1 signaling on Th17/Treg immune imbalance in psoriasis vulgaris (PV).

Materials and Methods

Notch1, Hes-1, RORγt, Foxp3, IL-17, and IL-10 mRNA expression, as well as Th17 and Treg cell percentages in peripheral CD4⁺ T cells, were detected by real-time quantitative RT-PCR and flow cytometry, and serum concentrations of IL-17 and IL-10 were detected by ELISA in 36 PV patients and 32 healthy controls. Additionally, CD4⁺ T cells from 12 PV patients were treated with γ-secretase inhibitor DAPT, and the above indexes were measured.

Results

PV patients presented distinct Th17/Treg immune imbalance and highly expressed Notch1 and Hes-1 mRNA levels, which were positively correlated with psoriasis area and severity index (PASI) and the ratios of Th17/Treg and RORγt/Foxp3. DAPT treatment resulted in the obvious downregulation of Th17 cell percentage in cocultured CD4⁺ T cells, RORγt and IL-17 mRNA levels, and IL-17 concentration in cell-free supernatant from cocultured CD4⁺ T cells of PV patients in a dose-dependent manner, while there was no significant influence on Treg cell percentage, Foxp3, and IL-10 expression, therefore leading to the recovery of Th17/Treg immune imbalance.

Conclusion

Notch1 signaling may contribute to the pathogenesis of PV by regulating Th17/Treg immune imbalance.

Regulatory B cells induced by ultraviolet B through toll-like receptor 4 signalling contribute to the suppression of contact hypersensitivity responses in mice

BACKGROUND

Ultraviolet (UV) B irradiation is known to suppress contact hypersensitivity (CHS) responses in mouse models by suppressing immune responses. However, the cellular mechanisms responsible for UVB-induced systemic suppression remain unclear. Regulatory B cells have been reported to play an inhibitory role during CHS. It is presently unknown whether regulatory B cells contribute to the effect of UVB phototherapy.

OBJECTIVE

To investigate the inductive effect of UVB on regulatory B cells and the underlying mechanisms by using a CHS mouse model.

METHODS

CHS was induced with oxazolone, and evaluated by histopathology, flow cytometry, and quantitative real-time polymerase chain reaction.

RESULT

We found that UVB irradiation induced regulatory B cell expansion and ameliorated CHS. UVB-induced regulatory B cells contribute to systemic immunosuppression by inhibiting the proliferation of T cells. Moreover, we determined that toll-like receptor (TLR) 4, the expression of which was upregulated in B cells after UVB exposure, played an essential role in the induction of regulatory B cells.

CONCLUSION

Our data identified regulatory B cells as regulators of UVB-induced immunosuppression in CHS, and suggest the importance of the UVB-TLR4 axis in the generation of regulatory B cells.

Desired response to phototherapy vs photoaggravation in psoriasis: what makes the difference?

Psoriasis commonly responds beneficially to UV radiation from natural sunlight or artificial sources. Therapeutic mechanisms include the proapoptotic and immunomodulating effects of UV, affecting many cells and involving a variety of pro- and anti-inflammatory cytokines, downregulating the Th17/IL-23 response with simultaneous induction of regulatory immune cells. However, exposure to UV radiation in a subset of psoriasis patients leads to exacerbation of the disease. We herein shed light on the predisposing factors of photosensitive psoriasis, including genetics (such as HLA-Cw*0602 or CARD14), gender and coexisting photodermatoses such as polymorphic light eruption (PLE) in the context of potential molecular mechanisms behind therapeutic photoresponsiveness or photoaggravation. UV-induced damage/pathogen-associated molecular patterns, damage to self-coding RNA (signalling through Toll-like receptors), certain antimicrobial peptides and/or inflammasome activation may induce innate immunity, leading to psoriasis at the site of UV exposure when there is concomitant, predisposing resistance against UV-induced suppression of the adaptive immune response (like in PLE) that otherwise would act to reduce psoriasis.

Expression of miRNA 155, FOXP3 and ROR gamma, in children with moderate and severe atopic dermatitis

BACKGROUND

Atopic dermatitis is a disease characterized by a chronic inflammatory process in the skin, but its link to miRNA 155 is less known. The aim of the study was to evaluate the expression of microRNA155, and T helper type 17 cells and Treg cells in children with atopic dermatitis.

METHODS

The study population consisted of: children seen for atopic dermatitis at the outpatient ambulatory of Dermatology at the Children Hospital Regina Margherita, Torino, Italy (N.=23); healthy control subjects (N.=23). Blood samples were taken during routine control analysis and the expression of miRNA 155 and the production of FOXP3 and RORγ was determined using PCR real time.

RESULTS

The analysis of miR-155 shows that the over-expression of miR-155 is statistically significant (P=0.0040) in the group of patients with atopic dermatitis compared to the healthy control group. Analysis of mRNAs of FOXP3 and RORγ shows a FOXP3 mRNA expression statistically higher in the group of patients (P=0.0057). The Th17 / Treg ratio is significantly smaller in patients with atopic dermatitis (P=0.0012). Also the ratio miR-155/Th17/Treg is larger in the group of patients with atopic dermatitis (P=0.0002).

CONCLUSIONS

Our results suggest that increased miR-155 and FOXP3 and RORγ responses may provide a link to immune dysregulation associated with atopic dermatitis. Although a point-by-point correlation between miR-155 and the ratio Th17/Treg is not demonstrated, our findings shows that these two elements do not appear to be completely unrelated to each other.

Photochemotherapy and Graft-versus-Leukemia Reaction in Acute Leukemia: Tumor Immunity and Survival Are Dependent on Timing of Photochemotherapy of the Skin

BACKGROUND

Cure of acute leukemia after transplantation is mediated by the grafted cells. We investigated the graft-versus-leukemia effect (GVL) in patients with cutaneous acute graft-versus-host disease (GVHD) treated with photochemotherapy (psoralen and ultraviolet light type A).

METHOD

Forty-seven patients with acute leukemia were followed 5,000 days after transplantation to assess survival and GVL by multivariate analysis. The primary predictor was time to treatment of cutaneous acute GVHD by photochemotherapy separated into treatment start during the first week of acute GVHD versus after the first week of acute GVHD.

RESULTS

Photochemotherapy started after the first week of acute GVHD predicted GVL with a hazard ratio (HR) of 3.94 (95% confidence interval, CI, 1.67-9.33, p = 0.0018) and survival with preserved GVL with an HR of 2.63 (95% CI 1.30-5.32, p = 0.007). The effects on GVL and survival with preserved GVL were present regardless of whether the patients were transplanted in remission or relapse (p < 0.05). Chronic GVHD came earlier in the group that started photochemotherapy after 1 week of acute GHVD, but chronic GVHD did not increase the GVL.

CONCLUSION

The timing of photochemotherapy after cutaneous acute GVHD may direct the GVL and predict long-term leukemia-free survival.

The role of regulatory T cells and genes involved in their differentiation in pathogenesis of selected inflammatory and neoplastic skin diseases. Part II: The Treg role in skin diseases pathogenesis

Regulatory FOXP3+ T cells (Tregs) constitute 5% to 10% of T cells in the normal human skin. They play an important role in the induction and maintenance of immunological tolerance. The suppressive effects of these cells are exerted by various mechanisms including the direct cytotoxic effect, anti-inflammatory cytokines, metabolic disruption, and modulation of the dendritic cells function. The deficiency of Treg cells number or function are one of the basic elements of the pathogenesis of many skin diseases, such as psoriasis, atopic dermatitis, bacterial and viral infections. They also play a role in the pathogenesis of T cell lymphomas of the skin (cutaneous T cell lymphomas - CTCL), skin tumors and mastocytosis. Here, in the second part of the cycle, we describe dysfunctions of Tregs in selected skin diseases.

The paradox of Th17 cell functions in tumor immunity

Immune system acts as a host defensive mechanism protecting against attacking pathogens and transformed cells, including cancer cells. Th17 cells are a specific subset of T helper lymphocytes determined by high secretion of IL-17 and other inflammatory cytokines. Th17 cells increase tumor progression by activating angiogenesis and immunosuppressive activities. They can also mediate antitumor immune responses through recruiting immune cells into tumors, stimulating effector CD8+ T cells, or surprisingly by altering toward Th1 phenotype and producing IFN-γ, so Th17 cells are supposed as a double-edged sword in cancer. A comprehensive approach to indicating the activity of Th17 cells in tumor progression could help in the planning of new therapeutic approaches specially targeting Th17 cells in cancer.

Psoriasis and Cardiovascular Comorbidities: Focusing on Severe Vascular Events, Cardiovascular Risk Factors and Implications for Treatment

Psoriasis is a common and chronic inflammatory disease of the skin. It may impair the physical and psychosocial function of patients and lead to decreased quality of life. Traditionally, psoriasis has been regarded as a disease affecting only the skin and joints. More recently, studies have shown that psoriasis is a systemic inflammatory disorder which can be associated with various comorbidities. In particular, psoriasis is associated with an increased risk of developing severe vascular events such as myocardial infarction and stroke. In addition, the prevalence rates of cardiovascular risk factors are increased, including hypertension, diabetes mellitus, dyslipidemia, obesity, and metabolic syndrome. Consequently, mortality rates have been found to be increased and life expectancy decreased in patients with psoriasis, as compared to the general population. Various studies have also shown that systemic treatments for psoriasis, including methotrexate and tumor necrosis factor-α inhibitors, may significantly decrease cardiovascular risk. Mechanistically, the presence of common inflammatory pathways, secretion of adipokines, insulin resistance, angiogenesis, oxidative stress, microparticles, and hypercoagulability may explain the association between psoriasis and cardiometabolic disorders. In this article, we review the evidence regarding the association between psoriasis and cardiovascular comorbidities, focusing on severe vascular events, cardiovascular risk factors and implications for treatment.