Immunomodulation at the initiation of phototherapy and photochemotherapy

UV-based therapy

UV phototherapy has a long history of use for the treatment of select diseases in dermatology. Its use has evolved into more effective and targeted modalities, including psoralen + UV-A photochemotherapy, narrowband UV-B, excimer laser, and UV-A1 phototherapy. With its proven record of efficacy and safety, UV phototherapy is an excellent option in the treatment of an ever-growing number of skin conditions.

Primary cutaneous T-cell lymphoma (mycosis fungoides and Sézary syndrome): part II. Prognosis, management, and future directions

Both mycosis fungoides (MF) and Sézary syndrome (SS) have a chronic, relapsing course, with patients frequently undergoing multiple, consecutive therapies. Treatment is aimed at the clearance of skin disease, the minimization of recurrence, the prevention of disease progression, and the preservation of quality of life. Other important considerations are symptom severity, including pruritus and patient age/comorbidities. In general, for limited patch and plaque disease, patients have excellent prognosis on ≥1 topical formulations, including topical corticosteroids and nitrogen mustard, with widespread patch/plaque disease often requiring phototherapy. In refractory early stage MF, transformed MF, and folliculotropic MF, a combination of skin-directed therapy plus low-dose immunomodulators (eg, interferon or bexarotene) may be effective. Patients with advanced and erythrodermic MF/SS can have profound immunosuppression, with treatments targeting tumor cells aimed for immune reconstitution. Biologic agents or targeted therapies either alone or in combination--including immunomodulators and histone-deacetylase inhibitors--are tried first, with more immunosuppressive therapies, such as alemtuzumab or chemotherapy, being generally reserved for refractory or rapidly progressive disease or extensive lymph node and metastatic involvement. Recently, an increased understanding of the pathogenesis of MF and SS with identification of important molecular markers has led to the development of new targeted therapies that are currently being explored in clinical trials in advanced MF and SS.

Phototherapy in psoriasis: a review of mechanisms of action

BACKGROUND

Phototherapy is one of the most efficacious treatment options for psoriasis. New, emerging studies are beginning to define the biologic mechanisms by which phototherapy improves psoriasis.

METHODS

To provide an overview of the mechanisms thought to be responsible for the therapeutic effects of phototherapy, a review was performed on all relevant published studies in the Medline database from January 1, 1985, to August 15, 2011.

FINDINGS

Four categories of action were proposed in the literature to describe the effects of phototherapy in psoriasis: (1) alteration of the cytokine profile, (2) induction of apoptosis, (3) promotion of immunosuppression, and (4) all other mechanisms.

CONCLUSIONS

Phototherapy acts through a combination of pathways to confer therapeutic benefits in psoriasis, and these different modalities may help explain its particular usefulness in treating this cutaneous disease.

Phototherapy with narrowband vs broadband UVB

Phototherapy with ultraviolet (UV) radiation of wavelengths between 280 and 320 nm (UVB) is a safe and effective treatment for a variety of diseases. In addition to standard broadband UVB (bUVB), narrowband phototherapy with fluorescent bulbs emitting near monochromatic UV around 311 nm (nUVB) has become an important treatment for diseases such as psoriasis, atopic dermatitis and vitiligo. In addition to these indications, the number of diseases for which nUVB phototherapy is reported to be effective is continuously growing. The differential effects of nUVB phototherapy in comparison to other UV wavelengths as well as established and new indications for this treatment modality are reviewed.

An update and guidance on narrowband ultraviolet B phototherapy: a British Photodermatology Group Workshop Report

Summary These guidelines for use of narrowband (TL-01) ultraviolet B have been prepared for dermatologists by the British Photodermatology Group on behalf of the British Association of Dermatologists. They present evidence-based guidance for treatment of patients with a variety of dermatoses and photodermatoses, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of background photobiology.

Monochromatic excimer light (308 nm) in patch-stage IA mycosis fungoides

Recently, numerous studies have been reported concerning the treatment of early-stage mycosis fungoides (MF) with narrowband (311-nm) UVB, claiming a beneficial response. We have used for the first time a 308-nm monochromatic excimer light, a new kind of xenon-chloride lamp, in the treatment of patch stage IA MF. We treated 7 patch lesions in 4 patients with unequivocal clinicopathologic diagnosis of MF. All lesions achieved clinical and histologic complete remission. The number of weekly sessions varied from 4 to 11 (mean 6.5; median 5.5). The total UVB 308-nm irradiation dose ranged from 5 to 9.3 J/cm(2) (mean 7.1 J/cm(2); median 7 J/cm(2)). All lesions remained in stable complete remission after a follow-up of 3 to 28 months. No remarkable side effects were reported. Our preliminary results suggest that monochromatic excimer light phototherapy is a possibly very useful treatment modality in patch stage IA MF.

Monochromatic excimer light (308 nm): an immunohistochemical study of cutaneous T cells and apoptosis-related molecules in psoriasis

BACKGROUND

Various types of UVB radiation source (290-320 nm) are used in treating psoriasis and their therapeutic mechanism has been attributed to immunosuppressive properties. Recently, a new UVB source generated by a 308-nm excimer laser has been introduced for the treatment of psoriasis.

OBJECTIVE

In this study we investigated the immunohistochemical evaluation of T cells and the expression of various apoptosis-related molecules in the psoriatic hyperproliferative skin before and after treatment with 308-nm monochromatic excimer light (MEL).

METHODS

Ten patients (three women and seven men), ranging in age from 29 to 79 years, affected by plaque-type psoriasis vulgaris, were treated with MEL. Biopsies from psoriatic lesions of MEL-treated sites were taken before, 24 h and/or 48 h after the first irradiation and analysed by the immunophosphatase alkaline technique (APAAP).

RESULTS

MEL treatment was found to cause a significant decrease in the rate of proliferation of keratinocytes and a relevant depletion of T cells in all psoriatic lesions, 48 h after the first irradiation: 308 nm light eliminated T cells from the psoriatic epidermis and also from the dermis, highlighting the ability of this UVB source to penetrate the skin compared with normal UVB and establish direct cytotoxic action on T cells infiltrating skin lesions. Rapid clearing of psoriatic lesions involves potential molecular targets of UVB in T cells including p53, which is upregulated after direct irradiation with 308-nm UVB. Moreover, Bcl-2 expression in healing psoriasis epidermis after MEL treatment is significantly decreased compared with untreated skin and the TUNEL (TdT-mediated dUTP-biotin nick end labelling) technique revealed the presence of relevant apoptotic keratinocytes in the irradiated epidermis.

CONCLUSIONS

These results indicate that psoriatic skin after monochromatic excimer light therapy is associated with significant T-cell depletion and alterations of apoptosis-related molecules accompanied by a decreased proliferation index and clinical remission.

Narrowband UVB and psoralen-UVA in the treatment of early-stage mycosis fungoides: a retrospective study

BACKGROUND

Treatment of early-stage mycosis fungoides (MF) consists of topical steroids, phototherapy (UVB), photochemotherapy (psoralen plus UVA [PUVA]), topical nitrogen mustard, or total skin electron-beam irradiation. It has been reported that the same effective UVB dose is safer than PUVA regarding carcinogenicity and produces fewer side effects. Narrowband UVB (311 nm) results in less irritation and erythema and is more effective compared with broadband UVB.

OBJECTIVE

Our purpose in this retrospective study was to analyze the response to treatment, relapse-free interval, and irradiation dose in 56 patients with early-stage MF (stage Ia and Ib). A total of 21 patients were treated with narrowband UVB (311 nm); 35 patients were treated with PUVA.

RESULTS

Narrowband UVB treatment led to complete remission in 17 of 21 patients (81%), partial remission in 4 of 21 (19%), and none showed progressive disease. PUVA treatment led to complete remission in 25 of 35 patients (71%), partial remission in 10 of 35 (29%), and none showed progressive disease. The mean relapse-free interval for patients treated with UVB was 24.5 months (range, 2-66 months) and for patients treated with PUVA, 22.8 months (range, 1-43 months).

CONCLUSION

Narrowband UVB therapy for patients with early-stage MF is an effective treatment modality. It has several advantages over treatment with broadband UVB and PUVA. When treating patients with early-stage MF it may be beneficial to start with narrowband UVB therapy and, if there is progression or no response, switch to PUVA therapy.

Narrowband UV-B phototherapy in the treatment of cutaneous graft versus host disease

Graft versus host disease (GVHD) is an important problem following allogenic bone marrow transplantation (BMT). The beneficial effects of photochemotherapy with psoralens plus UVA irradiation (PUVA) have been described repeatedly; however, PUVA is limited by a wide range of unwanted effects. A novel improved form of UV-B phototherapy, narrowband UV-B, has been proven to be very effective in T-cell mediated dermatoses. Therefore, we investigated the effect of narrowband UV-B phototherapy (5 times per week) in 10 patients with cutaneous GVHD (grade 2-3) resistant to standard immunosuppressive drugs. It was tolerated well by all patients, and no side effects were observed. Skin lesions showed complete clearance in 7 out of 10 patients within 3 to 5 weeks. 3 patients showed significant improvement of GVHD. We suggest that narrowband UV-B phototherapy is a nonaggressive treatment that may benefit patients with cutaneous GVHD who already take high doses of immunosuppressive drugs.

Influence of ultraviolet B exposure on immune responses following hepatitis B vaccination in human volunteers

Exposure to ultraviolet radiation can modulate immune responses in animal and humans. Remarkably, the ultraviolet-induced immunosuppression is not restricted to the exposed skin but is also found at other body sites, i.e., systemic immunosuppression. Effects of ultraviolet radiation on infections cannot be determined by experimentation on humans, but the effects of ultraviolet on vaccination may serve as a model. Moreover, it is important in its own right to assess whether ultraviolet radiation affects vaccination responses. In this study the effect of ultraviolet B exposure on the development of immune responses after hepatitis B vaccination in human volunteers was investigated. To this end, 191 human volunteers were vaccinated against hepatitis B with the Engerix-B vaccine. Ninety-seven of them were prior to the first vaccination exposed to ultraviolet B on 5 consecutive days with one personal minimal erythema dose per day. At several time-points before and after the ultraviolet B exposure regimen and the vaccination, blood samples were taken. Parameters for specific as well as nonspecific cellular and humoral immunity were analyzed. It was demonstrated that ultraviolet B exposure prior to hepatitis B vaccination did not alter the cellular (lymphocyte stimulation test) nor the humoral (antibody titers) immune response against hepatitis B surface antigen significantly. In contrast, contact hypersensitivity to diphenylcyclopropenone was significantly suppressed after ultraviolet B exposure, as was natural killer cell activity. These latter results confirm earlier findings and demonstrate immunosuppressive effectiveness of the ultraviolet regimen. In summary, although natural killer cell activity and contact hypersensitivity responses were suppressed, the ultraviolet B radiation protocol did not alter the humoral nor the cellular immune responses against hepatitis B surface antigen after vaccination.

The effects of ultraviolet radiation on the human immune system

The adverse outcome of increased ultraviolet (UV) irradiation on human health is currently of concern. While many experiments have been carried out in rodent models, fewer have been designed to test the effects of UV exposure in human subjects. This review concentrates on the modulations induced in the human immune system by UV, and outlines changes in antigen presentation by Langerhans cells and macrophages, in the activities of natural killer cells and T cells, and in cytokine regulation. Precautionary measures which might be taken to help protect people against the immunosuppressive action of UV irradiation are considered.

Phototherapy for atopic eczema with narrow-band UVB

Management of atopic dermatitis has been less than satisfactory. Conventional therapy has not been particularly successful, and prolonged use of topical corticosteroids and systemic immunosuppressant drugs (eg, corticosteroids, cyclosporine, azathioprine) can result in severe cutaneous and systemic effects. We decided to evaluate the effect of UVB at 311 nm to treat 5 patients with moderate to severe atopic dermatitis. In each patient a mean cumulative dose of 9.2 J/cm2 was applied over a mean of 19 irradiations. Narrow-band UVB notably reduced atopic dermatitis after 3 weeks in all patients.

312-nanometer ultraviolet B light (narrow-band UVB) induces apoptosis of T cells within psoriatic lesions

Narrow-band (312 nm) ultraviolet B light (UVB) is a new form of therapy for psoriasis, but its mechanism of action is unknown. In a bilateral comparison clinical study, daily exposure of psoriatic plaques to broad-band UVB (290-320 nm) or 312-nm UVB depleted T cells from the epidermis and dermis of psoriatic lesions. However, 312-nm UVB was significantly more depleting in both tissue compartments. To characterize the mechanism of T cell depletion, assays for T cell apoptosis were performed on T cells derived from UVB-irradiated skin in vivo and on T cells irradiated in vitro with 312-nm UVB. Apoptosis was induced in T cells exposed to 50-100 mJ/cm2 of 312-nm UVB in vitro, as measured by increased binding of fluorescein isothiocyanate (FITC)-Annexin V to CD3(+) cells and by characteristic cell size/granularity changes measured by cytometry. In vivo exposure of psoriatic skin lesions to 312-nm UVB for 1-2 wk also induced apoptosis in T cells as assessed by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) reaction in tissue sections, by binding of FITC-Annexin V to CD3(+) T cells contained in epidermal cell suspensions, and by detection of apoptosis-related size shifts of CD3(+) cells. Induction of T cell apoptosis could be the main mechanism by which 312-nm UVB resolves psoriasis skin lesions.

Narrow-band (TL-01) ultraviolet B phototherapy for chronic plaque psoriasis: three times or five times weekly treatment?

Three and five times weekly narrow-band TL-01 (311-313 nm) ultraviolet (UV) B phototherapy regimens for chronic plaque psoriasis were compared in a randomized, observer-blinded, half-body, within-patient paired study. Twenty-one patients [13 men, eight women, age range 21-68 years, skin phototypes I (two patients), II (14) and III (five)] entered the study. Sixteen reached clearance or minimal residual activity (MRA) on both sides. Of the other five, three withdrew because they did not reach clearance or MRA on the 5x weekly side by a maximum of 30 treatments, one when he was satisfied with moderate improvement and one because of repeated failure to attend. Those who completed treatment reached clearance or MRA after a median of 35 days with 5x weekly treatment compared with 40 days with 3x weekly treatment (P = 0.007), but required a median of 23.5 compared with 17 UVB exposures (P = 0.001) and 94 minimal erythema dose multiples (MEDs) compared with 64 MEDs (P = 0.01). Fifteen (of 16) developed at least one episode of well-demarcated erythema during 5x weekly treatment compared with just three of 16 treated 3x weekly (P < 0.001). There was no significant difference between regimens in duration of remission. For this skin phototype I-III population, the more rapid clearance of psoriasis with 5x weekly phototherapy is not, for the majority of patients, sufficient to justify the extra exposures and higher UVB dose. We no longer use 5x weekly phototherapy for psoriasis.

Estimation of the effect of increasing UVB exposure on the human immune system and related resistance to infectious diseases and tumours

Exposure to UV light has, besides some beneficial effects (vitamin D production), many harmful effects on human health. UVB irradiation has been shown to suppress both systemic and local immune responses to a variety of antigens, including some microorganisms. However, it is still not known whether such immunomodulating effects may lead to an increase in the number and severity of certain tumours and/or infections in humans. We report herein the data provided by a project that was funded by the European Union (Programme Environment), and that was aimed at the estimation of the risk associated with increased UVB exposure due to ozone depletion regarding the deleterious effects on the immune system and related resistance to tumours and infections in humans. The data, obtained by the different research groups involved, were assembled and used to calculate for the first time a risk assessment for increased environmental exposure to UVB in human subjects.

Biological effects of narrow-band (311 nm TL01) UVB irradiation: a review

The narrow-band UVB (TL01) lamp (311 nm emission) was developed for use in phototherapy, as an alternative to a broad-band UVB source and to photochemotherapy, both of which have significant side effects and carry a risk of carcinogenesis. This new lamp has proved to be particularly effective at clearing psoriasis. It is now acknowledged that the TL01 lamp is probably 2-3 times more carcinogenic per minimum erythema dose than broad-band UVB, but the cumulative dose required in therapy is considerably less than when using broad-band UVB sources. In terms of irradiation dose, the TL01 lamp is about 5-10-fold less potent than broad-band UVB for erythema induction, hyperplasia, oedema, sunburn cell formation and Langerhans cell depletion from skin. However, the broad-band UVB to TL01 potency ratio for cis-urocanic acid formation in the skin is approximately unity. In addition, the TL01 lamp, as used in phototherapy, has relatively more suppressive effects than broad-band UVB on systemic immune responses as judged by natural killer cell activity, lymphoproliferation and cytokine responses. However, the TL01 lamp is less effective at reducing epidermal antigen presentation, inducing dendritic cell migration to lymph nodes draining irradiated sites and suppressing contact hypersensitivity at the doses tested. Therefore the use of the TL01 lamp in phototherapy should be considered carefully after weighing up its diverse effects on the skin and immune system.

Effects of phototherapy on the production of cytokines by peripheral blood mononuclear cells and on systemic antibody responses in patients with psoriasis

Exposure to ultraviolet B (UVB) radiation results in the suppression of many cell-mediated immune responses, and recent studies mice and murine cells in vitro suggest a shift from a T-helper 1 (Th1) to a Th2 type of response on irradiation. Active psoriasis is considered to be a Th1-type disorder, chiefly on the basis of the cytokines produced by inflammatory cells in psoriatic lesions. We investigated the effect of phototherapy in patients with psoriasis on the cytokine profile of mitogen-stimulated mononuclear cells from peripheral blood and the concentration of IgG subclasses and IgE in the plasma. Eight patients were irradiated with a broad-band UV source (Sylvania UV6; 280-400 nm) three times a week and another eight with a narrow-band UVB source (Philips TL-01; 311-313 nm). Peripheral blood was collected before therapy started and after 1-4 weeks of therapy. Peripheral blood mononuclear cells were stimulated in vitro with phytohemagglutinin; proliferation was measured by incorporation of tritiated thymidine and culture supernatants assayed for interleukin (IL)-2, -4 and -10 and gamma-interferon (IFN) by enzyme-linked immunosorbent assays. Lymphoproliferation was not consistently affected by 4 weeks of UV6 therapy, and there was also no consistent change in the production of IL-2, IL-10 or gamma-IFN. In contrast, 4 weeks of TL-01 therapy significantly suppressed lymphoproliferative responses. In addition the production of IL-2, IL-10 and gamma-IFN was lowered after 1 week of TL-01 therapy, and this was even more apparent after the treatment had been extended to 4 weeks. IL-4 concentrations were below detectable levels in all the samples throughout the study. The amounts of IgG1, -2, -3 and -4 and IgE in the plasma of the patients did not vary with either of the two phototherapies. Thus, although no evidence was obtained to indicate that UV6 exposures affected T-helper subsets in psoriasis, TL-01 inhibited the activity of both Th1 and Th2 subsets while not altering plasma antibody concentrations.