HIV, UV and immunosuppression

A review of the use of tanning beds as a dermatological treatment

Introduction

In-office phototherapy is an effective treatment for many dermatologic conditions, however, many patients are unable to adhere to the rigorous travel and time commitments sometimes needed. Tanning bed facilities are nearly ubiquitous in modern society and could represent a more convenient means to obtain ultraviolet (UV) exposure when office phototherapy is not feasible. The purpose of this study was to review available evidence on the use of tanning facilities as a treatment for dermatologic conditions.

Methods

PubMed was searched on February 2015 for “tanning beds” and “phototherapy”, and with some dermatologic conditions sensitive to UV light, including “psoriasis”, “mycosis fungoides”, “acne”, “atopic dermatitis” and “eczema”. From there, further articles were found using the reference sections of the initial papers. A similar methodology was used with the Google Scholar search engine. Only articles in English and prospective studies were included in this review.

Results

We found studies validating the use of tanning facilities for psoriasis treatment. Use as a treatment option for atopic dermatitis, mycosis fungoides, acne, scleroderma, vitiligo, and pruritus, as well as other UV sensitive dermatoses, may also be beneficial. This study is limited by the lack of double-blind, placebo-controlled trials, long-term follow-up studies, and meta-analyses for tanning facility use in dermatologic phototherapy, and by the lack of standardization of both tanning facilities and exposure dosing.

Conclusion

Unsupervised sun exposure is a standard recommendation for some patients to obtain phototherapy. Selected use of commercial tanning beds in the treatment of dermatologic conditions may be another useful and effective treatment for those patients with an inability to access office-based or home-based phototherapy.

Electronic supplementary material

The online version of this article (doi:10.1007/s13555-015-0071-8) contains supplementary material, which is available to authorized users.

UV-based therapy and vitamin D

The ultraviolet (UV) light spectrum has long been known to induce biologic effect on the skin. For a large number of cutaneous disorders, phototherapy and photochemotherapy are effective therapeutic options with excellent safety profiles and well-documented side effects. Despite their ease of administration and benefits, phototherapeutic treatment modalities require appropriate space for the equipment, trained staff, and patient education prior to initiating treatment. However, when the initial barriers to treatment can be overcome, UV therapy can offer patients significant relief from their cutaneous disease. Furthermore, UVB-based phototherapy can produce significant alteration to vitamin D levels. With the recent research implicating association of low vitamin D levels with a variety of health conditions, whether patients receiving phototherapy or, more specifically, those getting vitamin D supplement may be protected from these diseases remains to be established.

Ultraviolet phototherapy for pruritus

Ultraviolet-based therapy has been used to treat various pruritic conditions including pruritus in chronic renal failure, atopic dermatitis, HIV, aquagenic pruritus and urticaria, solar, chronic, and idiopathic urticaria, urticaria pigmentosa, polycythemia vera, pruritic folliculitis of pregnancy, breast carcinoma skin infiltration, Hodgkin's lymphoma, chronic liver disease, and acquired perforating dermatosis, among others. Various mechanisms of action for phototherapy have been posited. Treatment limitations, side effects, and common dosing protocols are reviewed.

Fototerapia

Fototerapia é utilizada para tratar uma grande variedade de dermatoses. Desde o século passado a fototerapia tem sido utilizada em várias modalidades, com irradiação UVA ou UVB. Está indicada para todos os tipo de dermatoses inflamatórias e com período crônico de evolução, como vitiligo, pasoríase, parapsoríase, linfomas cutâneos de células T, eczemas crônicos, demonstrando bons resultados terapêuticos. Pode ser utilizada como monoterapia ou associada a outras drogas, como retinóides, metotrexate, ciclosporina, com objetivo de diminuir o tempo de tratamento e as doses das medicações mencionadas. Como os demais tipos de tratamento, a fototerapia apresenta algumas limitações, como a necessidade de equipamentos específicos, a adesão do paciente, a possibilidade de indicação ao paciente e a dose cumulativa de irradiação UV. A fototerapia deve ser conduzida com seguimento criterioso para a obtenção de resposta efetiva com poucos efeitos colaterais.

The Effect of Ultraviolet Radiation on Human Viral Infections

Exposure to UV radiation is recognized to suppress cell-mediated immunity and therefore could adversely affect the course of a viral infection. Rodent models of viral infection confirm this possibility but the situation in human subjects is not so clear, apart from two exceptions. These are herpes simplex, in which sunlight exposure can cause reactivation, and certain papillomavirus types in which sunlight exposure can lead to the development of nonmelanoma skin cancer. In both cases, there are UV response elements in the viral genomes that alter the normal interactions between the viruses and the host following exposure, and UV-induced effects on the immune response occur in addition. These complex mechanisms are discussed, and the situation regarding UV radiation and viral exanthems plus other viruses, including the retroviruses, summarized. Finally viral vaccination is considered in the context of UV exposure and the importance of the host's genetic background emphasized. Further research is required to evaluate whether sunlight can significantly affect the resistance to common viral infections and vaccines.

Vitiligo in association with human immunodeficiency virus infection

Autoimmune disorders such as vitiligo have been previously reported in patients with human immunodeficiency virus (HIV) infection. We describe a case of vitiligo in association with HIV where a rising CD4 lymphocyte count due to highly active antiretroviral therapy (HAART) closely correlated with changes in the skin. This effect, to our knowledge, has not been previously observed.

HIV-associated pruritus: etiology and management

With the advent of highly active antiretroviral therapy (HAART), life-threatening opportunistic infection has become less common in patients with HIV infection and longevity has increased dramatically. With increased longevity, the problems of living with a chronic disease have become more prominent in this patient population. Disorders such as fat redistribution and metabolic abnormalities can result from antiviral medications and from HIV disease itself. Pruritus is one of the most common symptoms encountered in patients with HIV. The spectrum of skin diseases in such patients encompasses dermatoses of diverse etiologies; a few are peculiar to patients with HIV while others are not. Some of these conditions may cause severe and sometimes intractable pruritus that provokes scratching, picking, disfigurement, sleep loss, and significant psychological stress. Moreover, the expense of ongoing medical treatments can be daunting. Skin rash can sometimes be the initial presentation of HIV infection or serve as a harbinger of disease progression. Causes of pruritus include skin infections, infestations, papulosquamous disorders, photodermatitis, xerosis, drug reactions, and occasionally lymphoproliferative disorders. Drug eruptions are particularly common in patients who are HIV positive, presumably as a result of immune dysregulation, altered drug metabolism, and polypharmacy. Itching can also result from systemic diseases such as chronic renal failure, liver disease, or systemic lymphoma. Workup of pruritus should include a careful examination of the skin, hair, nails, and mucous membranes to establish a primary dermatologic diagnosis. If no dermatologic cause is found, a systemic cause or medication-related etiology should be sought. Idiopathic HIV pruritus is a diagnosis of exclusion and should only be considered when a specific diagnosis cannot be established. The management of HIV-associated pruritus should be directed at the underlying condition. Phototherapy has been found to be useful in the treatment of several HIV-associated dermatoses and idiopathic pruritus as well. Unfortunately, some of the treatments that have been suggested for patients with HIV are anecdotal or based on small uncontrolled studies. The last decade has seen a surge in the utilization of HAART which, to some degree, reconstitutes the immune system and ameliorates some dermatologic diseases. On the other hand, some skin diseases flare temporarily when HAART is started. Unless frank drug allergy is suspected, HAART does not need to be stopped.

Prediction of experimental data for an independent variable using the experimental data collected for other independent variables in a study of skin cancer caused by exposure to UV radiation

In this study, two algorithms (ONE and TWO) are introduced to determine the position of the t-distribution of variable V(i) (with 95% confidence) in the treated group in reference to the t-distribution of variable V(i) (with 95% confidence) in the control group of an experimental study involving UV radiation exposure of a group of rodents. The outcome of applying the two algorithms is two discretized files. A reduct of each file is generated using the rough sets methodology and then the measurements for one independent variable are predicted using the measurements of the other independent variables in the same reduct. The rough sets methodology and the fuzzy-rough classifier are used for this prediction. The results reveal that (1) algorithm TWO is the best, (2) the values for non-core variables are predicted with minimum accuracy of 87%, and (3) the prediction of values for core variables is not successful.

Health effects from stratospheric ozone depletion and interactions with climate change

The potential health effects of elevated levels of ambient UV-B radiation are diverse, and it is difficult to quantify the risks, especially as they are likely to be considerably modified by human behaviour. Nevertheless epidemiological and experimental studies have confirmed that UV radiation is a definite risk factor for certain types of cataract, with peak efficacy in the UV-B waveband. The causal link between squamous cell carcinoma and cumulative solar UV exposure has been well established. New findings regarding the genetic basis of skin cancer, including studies on genetically modified mice, have confirmed the epidemiological evidence that UV radiation contributes to the formation of basal cell carcinomas and cutaneous melanomas, For the latter, animal models have demonstrated that UV exposure at a very young age is more detrimental than exposure in adulthood. Although suppression of certain immune responses has been recognised following UV exposure, the impact of this suppression on the control of infectious and autoimmune diseases is largely unknown. However, studies on several microbial infections have indicated significant consequences in terms of symptoms or reactivation of disease. The possibility that the immune response to vaccination could be depressed by UV-B exposure is of considerable concern. Newly emerging possibilities regarding interactions between ozone depletion and global climate change further complicate the risk assessments for human health but might result in an increased incidence of cataracts and skin cancer, plus alterations in the patterns of certain categories of infectious and other diseases.

Amsterdam Cohort Study on HIV and AIDS: impact of exposure to UVR as estimated by means of a 2-year retrospective questionnaire on immune parameters in HIV positive males

We studied a group of HIV-infected homosexuals who participated in the Amsterdam Cohort Study on HIV and AIDS to investigate whether greater exposure to sunlight is associated with a less favorable course of some important immunological parameters. This was done because ultraviolet radiation (UVR) is potentially harmful to the cellular immunity and may enhance viral replication. The exposure to UVR was estimated by means of a 2-year retrospective questionnaire in 1997. Both a 2-year cumulative estimate and estimates by 3-monthly episodes were calculated. The associations with CD4+ T-cell count, CD4+/CD8+ T-cell ratio, and T-cell reactivity were investigated. First, the associations between the cumulative estimate and the individual slopes of these parameters during the 2 years covered by the questionnaire were explored by means of a robust regression analysis. Secondly, the short-term association with the estimate by episode was examined by means of a linear mixed-effect model for repeated measurements (LME). No statistically significant associations with the cumulative estimate were found. Although a trend to lower values of the immunological parameters studied after short-term greater exposure in the LME model was observed, the differences were not statistically significant either. These findings suggest that exposure to sunlight does not have a suppressive effect on the above mentioned immunological parameters in HIV-infected persons.

Seasonal influences on immunological parameters in HIV-infected homosexual men: searching for the immunomodulating effects of sunlight

In view of the capacity of ultraviolet radiation (UVR) to induce suppression of various immunological parameters and to enhance the viral replication of HIV, we investigated whether seasonal influences on immunological parameters that are relevant for HIV infection could be identified. As the sunny season is associated with high levels of ambient UVR, a decline of immunological parameters and an increase of the HIV viral load during the summer months might ensue. We analysed the immunological data of the HIV-infected homosexual men who participated in the Amsterdam Cohort Study on HIV infection and AIDS (1984-1996; n = 556). The effect of season on the individual development of various immunological parameters in time was examined by means of a random effects model for repeated measurements. Lower levels in the mean number of CD4+ T cells and the mean CD4+/CD8+ ratio were found during summer and spring, respectively (P = 0.0001/0.0001). For the CD8+ T cells, high mean values were observed both in April and September (P = 0.0001). The highest T-cell reactivity values were found during the summer (P = 0.0001). No effect of season on the viral load was established. The seasonal effect on CD4+ T cells seemed to be more pronounced at a more advanced stage of the HIV infection. It is concluded that the lower CD4+ T-cell counts during summer support the notion that solar UVR may have a suppressive effect on the cellular immunity of HIV-infected persons. However, whether this observation can be attributed to the effect of ambient UVR solely is questionable, as the other immunological parameters follow different seasonal courses and other reports suggest that both internal and environmental factors influence immunological parameters.

Dissociation of innate and adaptive immunity by UVB irradiation

Increasing ultraviolet-B irradiation (UVB) resulting from diminution of stratospheric ozone is becoming a serious international problem. UVB irradiation exerts not only carcinogenic effects on animals but also causes them to become vulnerable to infections by modulating their immune responses. UVB irradiation suppresses innate immune functions of cells such as macrophages, neutrophils, Langerhans cells, dendritic cells, and the serum component, complement. UVB irradiation also causes changes in cytokine profiles, represented by the induction of a paradigm switch involving Th1/Th2 phenotypes. According to earlier studies, Th1 responses are suppressed, whereas Th2 activities are augmented by UVB irradiation. These immune modulations are caused by several pathways via cytokines and neuropeptides, and eventually may lead to increasing incidences of infection, allergy, and cancer. We have reviewed reports concerning UVB-irradiation induced immune modulation from the viewpoint of risks for human diseases and, in addition, for ecosystems and immunity of lower animals.

Effects of solar radiation on the human immune system

On UV irradiation of the skin, a complex cascade of immunological changes results, initiated by cutaneous chromophores and ending in suppression of some local and systemic immune responses. In this review, the stages in this process are outlined first, concentrating on the roles of DNA and urocanic acid as photoreceptors. Evidence indicating UV-induced immunomodulation of delayed hypersensitivity and resistance to infectious diseases in human subjects follows. Aspects of genetic susceptibility to the immunosuppressive effects of UV exposure and extrapolation of the data obtained in animal models to the human situation are included. Finally uncertain and unknown factors relating to the impact of UV on the human immune system are discussed.

Retroviruses and psoriasis

Psoriasis occurs with at least undiminished frequency in HIV infected individuals. The behaviour of psoriasis in HIV disease is of interest, both in terms of pathogenesis and therapy, because of the background of profound immunodysregulation. It is paradoxical that, while drugs that target T lymphocytes are effective in psoriasis, the condition should be exacerbated by HIV infection. Antiretroviral therapy may improve psoriasis in tandem with improvement in the overall clinical and virological condition of the patient. The aetiopathogenesis of psoriasis is unknown but genetic and environmental factors are thought to be involved. There are controversial issues regarding the immunological basis of psoriasis and the role of CD4+ versus CD8+ T lymphocytes. Current opinion favours an autoimmune basis for psoriasis, although the precipitating activating signal(s) within psoriatic plaques remains unknown. The immunodysregulation resulting from HIV infection may trigger psoriasis in those genetically predisposed by the Cw*0602 allele. Since CD8+ T cells recognize antigen in the context of class I molecules, the identification of a human leucocyte antigen class I association in HIV-associated psoriasis strengthens the argument for an important role for CD8+ T lymphocytes in the immunopathogenesis of psoriasis. HLA-Cw*0602 could act as a cross-reactive target for cytotoxic T lymphocytes responding to processed peptides from microorganisms. Human retrovirus-5 is a recently described, partially characterized retrovirus and has been implicated in the pathogenesis of psoriatic arthropathy but not psoriasis.