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Rueter K, Jones AP, Siafarikas A, Chivers P, Prescott SL, Palmer DJ. The Influence of Sunlight Exposure and Sun Protecting Behaviours on Allergic Outcomes in Early Childhood. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18105429. [PMID: 34069576 PMCID: PMC8161152 DOI: 10.3390/ijerph18105429] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/11/2021] [Accepted: 05/16/2021] [Indexed: 01/22/2023]
Abstract
The dramatic rise in allergic disease has occurred in tandem with recent environmental changes and increasing indoor lifestyle culture. While multifactorial, one consistent allergy risk factor has been reduced sunlight exposure. However, vitamin D supplementation studies have been disappointing in preventing allergy, raising possible independent effects of ultraviolet (UV) light exposure. The aim of this study was to examine whether UV light exposure influences the development of allergic disease in early childhood. Direct sunlight exposure (290-380 nm) in early infancy was measured via UV dosimeters. Outdoor exposure, sun protective behaviours, and allergy outcomes were assessed over the first 2.5 years of life with clinical assessment appointments at 3, 6, 12 and 30 months of age. Children with eczema had less (p = 0.038) direct UV light exposure between 0-3 months of age (median (IQR) 747 (473-1439) J/m2) than children without eczema (median (IQR) 1204 (1717-1843) J/m2); and less outdoor exposure time (7 min/day) between 11 a.m. and 3 p.m. compared to children without eczema (20 min/day, p = 0.011). These associations were seen independent of vitamin D status, and after adjusting for other potential confounders. Whilst we could not find any associations between direct UV light exposure and other allergic disease outcomes, exposure to UV light appears to be beneficial in reducing the risk of eczema development in early childhood. Further research is required to determine optimal levels of UV light exposure while balancing the potential risks.
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Affiliation(s)
- Kristina Rueter
- School of Medicine, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia; (K.R.); (A.S.); (S.L.P.)
- Department of Immunology and Dermatology, Perth Children’s Hospital, 15 Hospital Avenue, Nedlands 6009, Australia
- inVIVO Planetary Health, Group of the Worldwide Universities Network (WUN), 6010 Park Ave, West New York, NJ 07093, USA
| | - Anderson P. Jones
- Telethon Kids Institute, University of Western Australia, 15 Hospital Avenue, Nedlands 6009, Australia;
| | - Aris Siafarikas
- School of Medicine, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia; (K.R.); (A.S.); (S.L.P.)
- Telethon Kids Institute, University of Western Australia, 15 Hospital Avenue, Nedlands 6009, Australia;
- Department of Endocrinology, Perth Children’s Hospital, 15 Hospital Avenue, Nedlands 6009, Australia
- Institute for Health Research, The University of Notre Dame Australia, Perth 6160, Australia;
| | - Paola Chivers
- Institute for Health Research, The University of Notre Dame Australia, Perth 6160, Australia;
- School of Medical and Health Science, Edith Cowan University, Perth 6027, Australia
| | - Susan L. Prescott
- School of Medicine, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia; (K.R.); (A.S.); (S.L.P.)
- Department of Immunology and Dermatology, Perth Children’s Hospital, 15 Hospital Avenue, Nedlands 6009, Australia
- inVIVO Planetary Health, Group of the Worldwide Universities Network (WUN), 6010 Park Ave, West New York, NJ 07093, USA
- The ORIGINS Project, Telethon Kids Institute and Division of Paediatrics, University of Western Australia, 15 Hospital Avenue, Nedlands 6009, Australia
| | - Debra J. Palmer
- School of Medicine, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia; (K.R.); (A.S.); (S.L.P.)
- Telethon Kids Institute, University of Western Australia, 15 Hospital Avenue, Nedlands 6009, Australia;
- Correspondence:
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Hart PH, Norval M. The Multiple Roles of Urocanic Acid in Health and Disease. J Invest Dermatol 2021; 141:496-502. [DOI: 10.1016/j.jid.2020.07.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/15/2020] [Accepted: 07/30/2020] [Indexed: 12/31/2022]
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Rueter K, Jones AP, Siafarikas A, Lim EM, Prescott SL, Palmer DJ. In "High-Risk" Infants with Sufficient Vitamin D Status at Birth, Infant Vitamin D Supplementation Had No Effect on Allergy Outcomes: A Randomized Controlled Trial. Nutrients 2020; 12:nu12061747. [PMID: 32545250 PMCID: PMC7353265 DOI: 10.3390/nu12061747] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 06/07/2020] [Accepted: 06/09/2020] [Indexed: 12/20/2022] Open
Abstract
Lower vitamin D status at birth and during infancy has been associated with increased incidence of eczema and food allergies. The aim of this study was to investigate the effect of early infancy vitamin D supplementation on allergic disease outcomes in infants at “hereditary risk” of allergic disease, but who had sufficient vitamin D levels at birth. Here, we report the early childhood follow-up to 2.5 years of age of “high-risk” infants who participated in a double-blinded, randomized controlled trial. For inclusion in this trial, late gestation (36–40 weeks) maternal 25-hydroxyvitamin D levels needed to be ≥50 nmol/L. Infants were randomized to either oral vitamin D supplementation of 400 IU/day (n = 97) or a placebo (n = 98) for the first six months of life. Vitamin D levels and allergic disease outcomes were followed up. There were no statistically significant differences in incidence of any medically diagnosed allergic disease outcomes or allergen sensitization rates between the vitamin D-supplemented and placebo groups at either 1 year or at 2.5 years of age. In conclusion, for “allergy high-risk” infants who had sufficient vitamin D status at birth, early infancy oral vitamin D supplementation does not appear to reduce the development of early childhood allergic disease.
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Affiliation(s)
- Kristina Rueter
- School of Medicine, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; (K.R.); (A.S.); (S.L.P.)
- Perth Children’s Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
- InVIVO Planetary Health, Group of the Worldwide Universities Network (WUN), 6010 Park Ave, West New York, NJ 07093, USA
| | - Anderson P. Jones
- Telethon Kids Institute, University of Western Australia, 15 Hospital Avenue, Nedlands, WA 6009, Australia;
| | - Aris Siafarikas
- School of Medicine, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; (K.R.); (A.S.); (S.L.P.)
- Perth Children’s Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
- Telethon Kids Institute, University of Western Australia, 15 Hospital Avenue, Nedlands, WA 6009, Australia;
| | - Ee-Mun Lim
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, WA 6009, Australia;
- Department of Clinical Biochemistry, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Nedlands, WA 6009, Australia
| | - Susan L. Prescott
- School of Medicine, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; (K.R.); (A.S.); (S.L.P.)
- Perth Children’s Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
- InVIVO Planetary Health, Group of the Worldwide Universities Network (WUN), 6010 Park Ave, West New York, NJ 07093, USA
- The ORIGINS Project, Telethon Kids Institute and Division of Paediatrics, University of Western Australia, 15 Hospital Avenue, Nedlands, WA 6009, Australia
| | - Debra J. Palmer
- School of Medicine, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; (K.R.); (A.S.); (S.L.P.)
- Telethon Kids Institute, University of Western Australia, 15 Hospital Avenue, Nedlands, WA 6009, Australia;
- Correspondence: ; Tel.: +61-8-6319-1750
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Hart PH, Norval M. Are there differences in immune responses following delivery of vaccines through acutely or chronically sun-exposed compared with sun-unexposed skin? Immunology 2019; 159:133-141. [PMID: 31593303 DOI: 10.1111/imm.13128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/24/2019] [Accepted: 10/03/2019] [Indexed: 12/18/2022] Open
Abstract
The majority of human vaccines are administered above the deltoid muscle of the arm, a site that is chronically sun-exposed in many people. It is known that exposure of the skin to the UV wavelengths in sunlight stimulates systemic immunosuppression, an outcome that is associated with reduced immunity to microbial infections in animal models. Here we consider whether immunization of humans through a UV-irradiated skin site will lead to a less effective immune response compared with immunization through an unexposed site. Studies showing that the efficacy of vaccination can be reduced when surrogates of increased levels of sun exposure, such as latitude of residence and season of the year, are considered. Results from a limited number of intervention experiments in humans demonstrate a similar pattern. To provide an explanation for these findings, changes in the number and functional potential of immune cells in chronically sun-exposed compared with unexposed skin are outlined. UV radiation-induced changes to skin cells are also relevant when considering skin sites for administration of immune-tolerizing peptides. The review provides the basis for further research into the effects of acute and chronic UV radiation exposure on skin cells in the context of vaccination.
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Affiliation(s)
- Prue H Hart
- Telethon Kids Institute, University of Western Australia, Perth, WA, Australia
| | - Mary Norval
- University of Edinburgh Medical School, Edinburgh, Scotland
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Bernard JJ, Gallo RL, Krutmann J. Photoimmunology: how ultraviolet radiation affects the immune system. Nat Rev Immunol 2019; 19:688-701. [PMID: 31213673 DOI: 10.1038/s41577-019-0185-9] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2019] [Indexed: 02/07/2023]
Abstract
Ultraviolet (UV) radiation is a ubiquitous component of the environment that has important effects on a wide range of cell functions. Short-wavelength UVB radiation induces sunburn and is a potent immunomodulator, yet longer-wavelength, lower-energy UVA radiation also has effects on mammalian immunity. This Review discusses current knowledge regarding the mechanisms by which UV radiation can modify innate and adaptive immune responses and how this immunomodulatory capacity can be both beneficial in the case of inflammatory and autoimmune diseases, and detrimental in the case of skin cancer and the response to several infectious agents.
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Affiliation(s)
- Jamie J Bernard
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA. .,Division of Dermatology, Department of Medicine, Michigan State University, East Lansing, MI, USA.
| | - Richard L Gallo
- Department of Dermatology, University of California, San Diego, La Jolla, CA, USA
| | - Jean Krutmann
- IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany.,Medical Faculty, Heinrich Heine University, Duesseldorf, Germany
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Rueter K, Jones AP, Siafarikas A, Lim EM, Bear N, Noakes PS, Prescott SL, Palmer DJ. Direct infant UV light exposure is associated with eczema and immune development. J Allergy Clin Immunol 2018; 143:1012-1020.e2. [PMID: 30366577 DOI: 10.1016/j.jaci.2018.08.037] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/16/2018] [Accepted: 08/17/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Suboptimal vitamin D levels during critical periods of immune development have emerged as an explanation for higher rates of allergic diseases associated with industrialization and residing at higher latitudes. OBJECTIVE We sought to determine the effects of early postnatal vitamin D supplementation on infant eczema and immune development. METHODS By using a double-blind randomized controlled trial, newborn infants were randomized to receive vitamin D supplementation (400 IU/d) or a placebo until 6 months of age. Some infants also wore personal UV dosimeters to measure direct UV light (290-380 nm) exposure. Infant vitamin D levels were measured at 3 and 6 months of age. Eczema, wheeze, and immune function outcomes were assessed at 6 months of age. RESULTS At 3 (P < .01) and 6 (P = .02) months of age, vitamin D levels were greater for the vitamin D-supplemented group than the placebo group, but there was no difference in eczema incidence between groups. Infants with eczema were found to have had less UV light exposure (median, 555 Joules per square meter [J/m2; interquartile range, 322-1210 J/m2]) compared with those without eczema (median, 998 J/m2 [interquartile range, 676-1577 J/m2]; P = .02). UV light exposure was also inversely correlated with IL-2, GM-CSF, and eotaxin production to Toll-like receptor ligands. CONCLUSION This study is the first to demonstrate an association between greater direct UV light exposures in early infancy with lower incidence of eczema and proinflammatory immune markers by 6 months of age. Our findings indicate that UV light exposure appears more beneficial than vitamin D supplementation as an allergy prevention strategy in early life.
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Affiliation(s)
- Kristina Rueter
- School of Medicine, University of Western Australia, Crawley, Australia; Princess Margaret Hospital, Subiaco, Australia; inVIVO Planetary Health, Group of the Worldwide Universities Network (WUN), West New York, NJ
| | - Anderson P Jones
- Telethon Kids Institute, University of Western Australia, Subiaco, Australia
| | - Aris Siafarikas
- School of Medicine, University of Western Australia, Crawley, Australia; Princess Margaret Hospital, Subiaco, Australia; Telethon Kids Institute, University of Western Australia, Subiaco, Australia
| | - Ee-Mun Lim
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Australia; Department of Clinical Biochemistry, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Nedlands, Australia
| | - Natasha Bear
- Department of Clinical Research and Education, Child Adolescent Health Service, Perth, Australia
| | - Paul S Noakes
- School of Medicine, University of Western Australia, Crawley, Australia; Telethon Kids Institute, University of Western Australia, Subiaco, Australia
| | - Susan L Prescott
- School of Medicine, University of Western Australia, Crawley, Australia; Princess Margaret Hospital, Subiaco, Australia; inVIVO Planetary Health, Group of the Worldwide Universities Network (WUN), West New York, NJ; Telethon Kids Institute, University of Western Australia, Subiaco, Australia
| | - Debra J Palmer
- School of Medicine, University of Western Australia, Crawley, Australia; Telethon Kids Institute, University of Western Australia, Subiaco, Australia.
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Hart PH, Norval M, Byrne SN, Rhodes LE. Exposure to Ultraviolet Radiation in the Modulation of Human Diseases. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2018; 14:55-81. [PMID: 30125148 DOI: 10.1146/annurev-pathmechdis-012418-012809] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
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.
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Affiliation(s)
- Prue H Hart
- Telethon Kids Institute, University of Western Australia, Perth, Western Australia 6008, Australia;
| | - Mary Norval
- University of Edinburgh Medical School, Edinburgh EH8 9AG, United Kingdom;
| | - Scott N Byrne
- Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales 2006, Australia; .,Westmead Institute for Medical Research, Westmead, New South Wales 2145, Australia
| | - Lesley E Rhodes
- Centre for Dermatology Research, Division of Musculoskeletal and Dermatological Sciences, School of Biological Sciences, and Faculty of Biology, Medicine, and Health, The University of Manchester and Salford Royal NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9PL, United Kingdom;
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Abhimanyu, Coussens AK. The role of UV radiation and vitamin D in the seasonality and outcomes of infectious disease. Photochem Photobiol Sci 2018; 16:314-338. [PMID: 28078341 DOI: 10.1039/c6pp00355a] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The seasonality of infectious disease outbreaks suggests that environmental conditions have a significant effect on disease risk. One of the major environmental factors that can affect this is solar radiation, primarily acting through ultraviolet radiation (UVR), and its subsequent control of vitamin D production. Here we show how UVR and vitamin D, which are modified by latitude and season, can affect host and pathogen fitness and relate them to the outcomes of bacterial, viral and vector-borne infections. We conducted a thorough comparison of the molecular and cellular mechanisms of action of UVR and vitamin D on pathogen fitness and host immunity and related these to the effects observed in animal models and clinical trials to understand their independent and complementary effects on infectious disease outcome. UVR and vitamin D share common pathways of innate immune activation primarily via antimicrobial peptide production, and adaptive immune suppression. Whilst UVR can induce vitamin D-independent effects in the skin, such as the generation of photoproducts activating interferon signaling, vitamin D has a larger systemic effect due to its autocrine and paracrine modulation of cellular responses in a range of tissues. However, the seasonal patterns in infectious disease prevalence are not solely driven by variation in UVR and vitamin D levels across latitudes. Vector-borne pathogens show a strong seasonality of infection correlated to climatic conditions favoring their replication. Conversely, pathogens, such as influenza A virus, Mycobacterium tuberculosis and human immunodeficiency virus type 1, have strong evidence to support their interaction with vitamin D. Thus, UVR has both vitamin D-dependent and independent effects on infectious diseases; these effects vary depending on the pathogen of interest and the effects can be complementary or antagonistic.
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Affiliation(s)
- Abhimanyu
- Clinical Infectious Diseases Research Initiative, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Anzio Rd, Observatory, 7925, Western Cape, South Africa.
| | - Anna K Coussens
- Clinical Infectious Diseases Research Initiative, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Anzio Rd, Observatory, 7925, Western Cape, South Africa. and Division of Medical Microbiology, Department of Pathology, University of Cape Town, Anzio Rd, Observatory, 7925, Western Cape, South Africa
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Guo B, Naish S, Hu W, Tong S. The potential impact of climate change and ultraviolet radiation on vaccine-preventable infectious diseases and immunization service delivery system. Expert Rev Vaccines 2014; 14:561-77. [PMID: 25493706 DOI: 10.1586/14760584.2014.990387] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Climate change and solar ultraviolet radiation may affect vaccine-preventable infectious diseases (VPID), the human immune response process and the immunization service delivery system. We systematically reviewed the scientific literature and identified 37 relevant publications. Our study shows that climate variability and ultraviolet radiation may potentially affect VPID and the immunization delivery system through modulating vector reproduction and vaccination effectiveness, possibly influencing human immune response systems to the vaccination, and disturbing immunization service delivery. Further research is needed to determine these affects on climate-sensitive VPID and on human immune response to common vaccines. Such research will facilitate the development and delivery of optimal vaccination programs for target populations, to meet the goal of disease control and elimination.
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Affiliation(s)
- Biao Guo
- Queensland University of Technology, School of Public Health and Social Work, D Wing, O Block, Victoria Park Road, Kelvin Grove, Brisbane, 4059, Australia
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Sleijffers A, Garssen J, Vos JG, Loveren H. Ultraviolet light and resistance to infectious diseases. J Immunotoxicol 2012; 1:3-14. [PMID: 18958636 DOI: 10.1080/15476910490438333] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Exposure to ultraviolet (UV) radiation, as in sunlight, can modulate immune responses in animals and humans. This immunomodulation can lead to positive health effects especially with respect to certain autoimmune diseases and allergies. However, UV-induced immunomodulation has also been shown to be deleterious. Experimental animal studies have revealed that UV exposure can impair the resistance to many infectious agents, such as bacteria, parasites, viruses, and fungi. Importantly, these effects are not restricted to skin-associated infections, but also concern systemic infections. UV radiation induces a multistep process, locally in the skin as well as systemically, that ultimately leads to immunosuppression. The first event is the absorption of "UV" photons by chromophores, or so-called photoreceptors, such as DNA and urocanic acid (UCA) in the upper cell layers of the skin. Upon absorption of UV radiation, trans-UCA isomerizes to the cis-isomer. Cis-UCA is likely the most important mediator of UV-induced immunosuppression, as this compound has been shown to modulate the induction of contact type hypersensitivity and delayed type hypersensitivity, allograft rejection, and the functions of monocytes and T-lymphocytes as well as natural killer cells. The real consequences of UV-induced immunomodulation on resistance to infectious diseases for humans are not fully known. Risk estimations have been performed through extrapolation of animal data, obtained from infection models, to the human situation. This estimation indicated that UV doses relevant to outdoor exposure can impair the human immune system sufficiently to have effects on resistance to infections, but also indicated that human data are necessary to further quantify and validate this risk estimation. Further information has been obtained from vaccination studies in human volunteers as ethical reasons prohibit studies with infectious agents. Studies in mice and human volunteers on the effects of prior UVB exposure on hepatitis B vaccination responses revealed suppressed cellular and humoral immune responses in mice but not in human volunteers. However, subgroups within the performed human volunteer study made by determination of cytokine polymorphisms or UVB-induced mediators, revealed that some individuals have suppressed hepatitis B vaccination responses after UVB exposure. Thus, it might be concluded that the human immune system can be affected by UVB exposure, and decreased resistance to infectious diseases can be expected after sun exposure.
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Affiliation(s)
- Annemarie Sleijffers
- Laboratory for Toxicology, Pathology and Genetics, National Institute of Public Health and the Environment, Bilthoven, The Netherlands
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Jeevan A, Formichella CR, Russell KE, Dirisala VR. Guinea pig skin, a model for epidermal cellular and molecular changes induced by UVR in vivo and in vitro: effects on Mycobacterium bovis Bacillus Calmette-Guérin vaccination. Photochem Photobiol 2012; 89:189-98. [PMID: 22882532 DOI: 10.1111/j.1751-1097.2012.01218.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 07/22/2012] [Indexed: 11/27/2022]
Abstract
Previously, we reported that ultraviolet B-radiation (UVR) suppressed Bacillus Calmette-Guérin (BCG) vaccine-induced resistance to Mycobacterium tuberculosis in guinea pigs (GP). Herein, we investigated the cellular and molecular changes within the irradiated GP epidermis and the in vivo effect of supernatants from UV-irradiated (200 J m(-2)) epidermal cells (UV-sup) on M. bovis BCG vaccination. UVR increased the number of nucleated keratinocytes in the skin, but caused a decrease in the proportions of CD25(+)T cells. In the spleen, UVR resulted in a decrease in the proportions of T-cell subsets including CD25(+)T cells, and major histocompatibility complex (MHC) class II(+) and CD14(+) cells. Similarly, significant up-regulation of several cytokine mRNAs including IL-10 was also observed. Furthermore, UV-sup significantly reduced the MHC class II expression in peritoneal cells and reduced T-cell proliferation to ConA. The proliferation to purified protein derivative (PPD) was restored to normal levels by anti-IL-10 antibody. The UV-sup when injected into BCG-vaccinated GP significantly diminished the skin test response and T-cell proliferation to PPD and up-regulated the expression of IL-10, IL-4, IL-1β and Foxp3 mRNAs in the lymph node or spleen. Thus, whole body UVR induces profound cellular and molecular changes and injection of UV-sup from epidermal cells mimics the effect of whole body UVR in BCG-vaccinated GP.
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Affiliation(s)
- Amminikutty Jeevan
- Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, College Station, TX, USA.
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The mechanisms and consequences of ultraviolet-induced immunosuppression in the skin and eye. Eye Contact Lens 2011; 37:176-84. [PMID: 21709488 DOI: 10.1097/icl.0b013e31821d7573] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ultraviolet radiation (UVR) of the skin results in immune suppression to antigens encountered shortly after the exposure. The pathways leading to the downregulation in immunity are complex, initiated by chromophores located at the surface of the skin and ending with the generation of immunosuppressive mediators and regulatory cells. Ultraviolet-induced immunosuppression can be considered not only as beneficial, such as in preventing chronic inflammatory responses and allergic and automimmune reactions, but it can also be detrimental, such as in the lack of control of skin tumors and infectious diseases. The eye is an immune privileged site through a wide variety of mechanisms that allow selected immune responses without causing inflammation. The role of UVR in altering immune responses in the eye is not clear and is discussed in relation to photokeratitis, herpetic stromal keratitis, and pterygium.
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The challenges of UV-induced immunomodulation for children's health. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 107:323-32. [PMID: 21875613 DOI: 10.1016/j.pbiomolbio.2011.07.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 07/26/2011] [Indexed: 02/01/2023]
Abstract
Exposure to solar ultraviolet radiation (UVR) is recognised to have both beneficial and harmful effects on human health. With regard to immune responses, it can lead to suppression of immunity and to the synthesis of vitamin D, a hormone that can alter both innate and adaptive immunity. The consequences in children of such UV-induced changes are considerable: first there are positive outcomes including protection against some photoallergic (for example polymorphic light eruption) and T cell-mediated autoimmune diseases (for example multiple sclerosis) and asthma, and secondly there are negative outcomes including an increased risk of skin cancer (squamous cell carcinoma, basal cell carcinoma and cutaneous malignant melanoma) and less effective control of several infectious diseases. Many uncertainties remain regarding the amount of sun exposure that would provide children with the most effective responses against the variety of immunological challenges that they are likely to experience.
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Modulation of the immune system by UV radiation: more than just the effects of vitamin D? Nat Rev Immunol 2011; 11:584-96. [PMID: 21852793 DOI: 10.1038/nri3045] [Citation(s) in RCA: 294] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Humans obtain most of their vitamin D through the exposure of skin to sunlight. The immunoregulatory properties of vitamin D have been demonstrated in studies showing that vitamin D deficiency is associated with poor immune function and increased disease susceptibility. The benefits of moderate ultraviolet (UV) radiation exposure and the positive latitude gradients observed for some immune-mediated diseases may therefore reflect the activities of UV-induced vitamin D. Alternatively, other mediators that are induced by UV radiation may be more important for UV-mediated immunomodulation. Here, we compare and contrast the effects of UV radiation and vitamin D on immune function in immunopathological diseases, such as psoriasis, multiple sclerosis and asthma, and during infection.
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Norval M, Halliday GM. The consequences of UV-induced immunosuppression for human health. Photochem Photobiol 2011; 87:965-77. [PMID: 21749399 DOI: 10.1111/j.1751-1097.2011.00969.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Exposure to UV radiation can cause suppression of specific immune responses. The pathways leading to the down-regulation are complex, starting from the absorption of UV photons by chromophores in the skin and ending with local and systemic changes in immune mediators, the generation of T and B regulatory cells and inhibition of effector and memory T cell activation. The consequences for human health are thought to be both beneficial and adverse. The former are illustrated by protection against polymorphic light eruption, and possible protection against T cell-mediated autoimmune diseases and asthma. The latter are illustrated by skin cancer, cutaneous lupus erythematosus and infectious diseases including vaccination. Many outstanding questions remain in this rapidly developing and controversial area, not least what advice to give the general public regarding their sun exposure. While considerable advances have been made in the development of strategies that preserve the health benefits of sunlight exposure and decrease its detrimental effects, further research is required before optimal levels of protection are achieved.
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Affiliation(s)
- Mary Norval
- Biomedical Sciences, University of Edinburgh, Edinburgh, Scotland.
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Norval M, Woods GM. UV-induced immunosuppression and the efficacy of vaccination. Photochem Photobiol Sci 2011; 10:1267-74. [PMID: 21713277 DOI: 10.1039/c1pp05105a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Exposure to ultraviolet radiation (UVR) suppresses immunity by complex pathways, initiated by chromophores located in the skin and ending with the generation of specific subsets of T and B regulatory cells. The primary and memory (recall) immune response to a wide variety of antigens, including microorganisms, can be reduced by UVR, leading to the possibility that the efficacy of vaccination could be similarly reduced. A limited number of animal models of vaccination demonstrate that this may indeed be the case. The situation in human subjects has not been rigorously assessed but there are indications from a variety of sources that UVR adversely affects the immune responses to several vaccines. These studies are reviewed and the implications for vaccine administration discussed. As vaccination represents a major public health measure world-wide for the control of an increasing number of common infections, it is important to maximise its efficacy; therefore further evaluation of UVR in the context of vaccination is required and warranted.
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Affiliation(s)
- Mary Norval
- Biomedical Sciences, University of Edinburgh Medical School, Teviot Place, Edinburgh, EH8 9AG, Scotland, UK.
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Rácz E, Prens EP, Kant M, Florencia E, Jaspers NG, Laman JD, de Ridder D, van der Fits L. Narrowband ultraviolet B inhibits innate cytosolic double-stranded RNA receptors in psoriatic skin and keratinocytes. Br J Dermatol 2011; 164:838-47. [PMID: 21143460 DOI: 10.1111/j.1365-2133.2010.10169.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND The mode of action of narrowband ultraviolet B (NB-UVB) therapy in clearing psoriasis is incompletely understood, and in vivo studies at the molecular level in patients undergoing NB-UVB therapy are limited. We previously demonstrated increased expression and activity of double-stranded RNA (dsRNA) receptors in psoriasis lesions, and suggested that this enhanced innate signalling contributed to the maintenance of psoriatic inflammation. OBJECTIVES We investigated whether NB-UVB affects dsRNA receptor expression and function in vivo as well as in vitro. METHODS Skin samples of patients with psoriasis undergoing NB-UVB treatment were analysed for epidermal messenger RNA (mRNA) expression of the various dsRNA receptors by microarray and quantitative reverse transcription-polymerase chain reaction. Primary human keratinocytes were irradiated with NB-UVB and stimulated with interferon (IFN)-α or IFN-γ, critical cytokines in psoriasis. The dsRNA analogue polyriboinosinic-polyribocytidylic acid was used to assess the functional responsiveness of the cells to dsRNA. RESULTS NB-UVB therapy of patients with psoriasis resulted in a significantly reduced mRNA expression of the activating dsRNA receptors MDA5 (IFIH1) and RIG-I (DDX58). On the other hand, expression of LGP2 (DHX58), toll-like receptor 3 (TLR3) and PKR (EIF2AK2) was not affected. In vitro, NB-UVB irradiation completely blocked the upregulation of four of the dsRNA receptors in primary human keratinocytes stimulated with IFN-α or IFN-γ, resulting in an attenuated inflammatory response to dsRNA. CONCLUSIONS Our results show that NB-UVB irradiation inhibits the local innate inflammatory response to dsRNA, and suggest a novel mechanism of action of NB-UVB phototherapy in psoriasis.
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Affiliation(s)
- E Rácz
- Departments of Dermatology Immunology Genetics, Erasmus MC, University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands
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Norval M, Lucas RM, Cullen AP, de Gruijl FR, Longstreth J, Takizawa Y, van der Leun JC. The human health effects of ozone depletion and interactions with climate change. Photochem Photobiol Sci 2011; 10:199-225. [PMID: 21253670 DOI: 10.1039/c0pp90044c] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Depletion of the stratospheric ozone layer has led to increased solar UV-B radiation (280-315 nm) at the surface of the Earth. This change is likely to have had an impact on human exposure to UV-B radiation with consequential detrimental and beneficial effects on health, although behavioural changes in society over the past 60 years or so with regard to sun exposure are of considerable importance. The present report concentrates on information published since our previous report in 2007. The adverse effects of UV radiation are primarily on the eye and the skin. While solar UV radiation is a recognised risk factor for some types of cataract and for pterygium, the evidence is less strong, although increasing, for ocular melanoma, and is equivocal at present for age-related macular degeneration. For the skin, the most common harmful outcome is skin cancer, including melanoma and the non-melanoma skin cancers, basal cell carcinoma and squamous cell carcinoma. The incidence of all three of these tumours has risen significantly over the past five decades, particularly in people with fair skin, and is projected to continue to increase, thus posing a significant world-wide health burden. Overexposure to the sun is the major identified environmental risk factor in skin cancer, in association with various genetic risk factors and immune effects. Suppression of some aspects of immunity follows exposure to UV radiation and the consequences of this modulation for the immune control of infectious diseases, for vaccination and for tumours, are additional concerns. In a common sun allergy (polymorphic light eruption), there is an imbalance in the immune response to UV radiation, resulting in a sun-evoked rash. The major health benefit of exposure to solar UV-B radiation is the production of vitamin D. Vitamin D plays a crucial role in bone metabolism and is also implicated in protection against a wide range of diseases. Although there is some evidence supporting protective effects for a range of internal cancers, this is not yet conclusive, but strongest for colorectal cancer, at present. A role for vitamin D in protection against several autoimmune diseases has been studied, with the most convincing results to date for multiple sclerosis. Vitamin D is starting to be assessed for its protective properties against several infectious and coronary diseases. Current methods for protecting the eye and the skin from the adverse effects of solar UV radiation are evaluated, including seeking shade, wearing protective clothing and sunglasses, and using sunscreens. Newer possibilities are considered such as creams that repair UV-induced DNA damage, and substances applied topically to the skin or eaten in the diet that protect against some of the detrimental effects of sun exposure. It is difficult to provide easily understandable public health messages regarding "safe" sun exposure, so that the positive effects of vitamin D production are balanced against the negative effects of excessive exposure. The international response to ozone depletion has included the development and deployment of replacement technologies and chemicals. To date, limited evidence suggests that substitutes for the ozone-depleting substances do not have significant effects on human health. In addition to stratospheric ozone depletion, climate change is predicted to affect human health, and potential interactions between these two parameters are considered. These include altering the risk of developing skin tumours, infectious diseases and various skin diseases, in addition to altering the efficiency by which pathogenic microorganisms are inactivated in the environment.
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Affiliation(s)
- M Norval
- Biomedical Sciences, University of Edinburgh Medical School, Edinburgh, EH8 9AG, Scotland.
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Abstract
Whereas animal studies are invaluable for screening various chemical and drugs for immunotoxic potential, such systems are necessarily limited in their predictive value for humans given the differences in physiology, immune system structure and function, and various other parameters between humans and nonhuman animals. However, prospective experimental studies in humans are not always practical or ethical. What is needed is an approach for combining animal data, human data collected in the course of clinical studies, and modern tools of bioinformatics and systems biology. In this chapter, we will explore current assays and methodologies for assessing immunotoxic potential in humans using this multi--parameter approach.
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Leng H, Luo X, Ma L, Kang K, Zheng Z. Reversal of ultraviolet B-induced immunosuppression by inhibition of the extracellular signal-regulated mitogen-activated protein kinase. PHOTODERMATOLOGY PHOTOIMMUNOLOGY & PHOTOMEDICINE 2009; 25:264-9. [PMID: 19747246 DOI: 10.1111/j.1600-0781.2009.00458.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Topical treatment of the specific inhibitor PD98059 (PD) for extracellular signal-regulated kinase (ERK)1/2 combined with ultraviolet B (UVB) exposure in an in vivo study was proposed to confirm the effectiveness of ERK1/2 involved in UVB-induced immunosuppression that was reversed by PD. METHODS Based on the mouse model of local UVB-induced immunosuppression [UVB exposure, followed by sensitization with dinitrofluorobenzene (DNFB) on the abdomen skin before challenge on the ear site], the PD was applied on the abdomen-irradiated area 1 h, immediately before and 6 h after UVB exposure, respectively. The baseline of ear thickness was measured and remeasured 24 h after the challenge of DNFB for evaluation of ear-swelling response. Histopathologically, the ear biopsies were taken for hematoxylin and eosin staining. RESULTS Mice that received PD post-irradiation treatment showed a statistically significant contact hypersensitivity compared with the UVB-irradiated mice (P<0.05), and paralleled with the biopsy showing a thickened epidermis with lymphocyte infiltration. Thus, the PD had abrogated the UV-induced local suppression of contact hypersensitivity. CONCLUSION The ERK1/2 mitogen-activated protein kinase (MAPK) pathway plays an important role in the local UVB-induced immunosuppression, and its specific inhibitor PD can arrest its function, resulting in protection against UVB-induced immunosuppression in the present in vivo study.
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Affiliation(s)
- Hong Leng
- Department of Dermatology, Hua-Shan Hospital, Fudan University, Shanghai, China
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Welsh MM, Karagas MR, Applebaum KM, Spencer SK, Perry AE, Nelson HH. A role for ultraviolet radiation immunosuppression in non-melanoma skin cancer as evidenced by gene-environment interactions. Carcinogenesis 2008; 29:1950-4. [PMID: 18641401 DOI: 10.1093/carcin/bgn160] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The genotoxic effects of ultraviolet (UV) radiation are well-known causes of skin cancers; however, UV radiation also suppresses the immune system, decreasing the body's surveillance for tumor cells. In experimental systems, UV radiation immunosuppression is at least partially mediated through urocanic acid (UCA), an UV radiation-absorbing molecule in the stratum corneum. We tested the hypothesis that genetic variation in the histidase gene (HAL), which catalyzes the formation of UCA in the skin, modifies risk of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) in a population-based study (914 BCC, 702 SCC and 848 controls). We observed no evidence of a main gene effect for the HAL I439V polymorphism (rs7297245) and BCC or SCC. However, we found a HAL genotype-sunburn interaction in association with BCC (P for interaction = 0.040) and SCC (P for interaction = 0.018). A HAL genotype-SCC association was observed primarily among women (odds ratio = 1.5, 95% confidence interval 1.1-2.2), and among women, we found an interaction between HAL genotype and oral contraceptive use on SCC risk (P = 0.040). The variant HAL allele likewise appeared to modify the SCC risk associated with glucocorticoid steroid usage (P for interaction = 0.0004). In conclusion, our findings are a first step in determining the genetic underpinnings of UV immune suppression and have identified important new genetic interactions contributing to the etiology of skin cancer.
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Affiliation(s)
- Marleen M Welsh
- Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA
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Gibbs NK, Tye J, Norval M. Recent advances in urocanic acid photochemistry, photobiology and photoimmunology. Photochem Photobiol Sci 2008; 7:655-67. [PMID: 18528548 DOI: 10.1039/b717398a] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Urocanic acid (UCA), produced in the upper layers of mammalian skin, is a major absorber of ultraviolet radiation (UVR). Originally thought to be a 'natural sunscreen', studies conducted a quarter of a century ago proposed that UCA may be a chromophore for the immunosuppression that follows exposure to UVR. With its intriguing photochemistry, its role in immunosuppression and skin cancer development, and skin barrier function, UCA continues to be the subject of intense research effort. This review summarises the photochemical, photobiological and photoimmunological findings regarding UCA, published since 1998.
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Affiliation(s)
- Neil K Gibbs
- Dermatological Sciences, University of Manchester Medical School, Stopford Building, Oxford Road, Manchester, UK M13 9PT.
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Norval M, McLoone P, Lesiak A, Narbutt J. The Effect of Chronic Ultraviolet Radiation on the Human Immune System†. Photochem Photobiol 2007; 84:19-28. [DOI: 10.1111/j.1751-1097.2007.00239.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Silva E, Herrera L, Edwards AM, Fuente J, Lissi E. Enhancement of Riboflavin-mediated Photo-Oxidation of Glucose 6-phosphate Dehydrogenase by Urocanic Acid¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb01543.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Norval M. The mechanisms and consequences of ultraviolet-induced immunosuppression. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2006; 92:108-18. [PMID: 16564073 DOI: 10.1016/j.pbiomolbio.2006.02.009] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Exposure to ultraviolet radiation (UVR) can result in immune suppression to antigens encountered within a few days of the irradiation. The process leading to the down-regulation in immune responses is complex. It is initiated by several photoreceptors located in the skin surface, namely DNA, trans-urocanic acid and membrane components. The absorption of UVR by these chromophores then leads to the release of a wide range of mediators that can affect antigen presenting cells locally or systemically. The final steps include the generation of antigen-specific T cells capable of regulating immunity. The consequences of the UV-induced changes in the skin immune system for the control of skin cancers, infectious diseases including vaccination, and autoimmune diseases are considered. Finally, the effects of active vitamin D, synthesised in the epidermis following UVR, are discussed in the context of the skin immune response.
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Affiliation(s)
- Mary Norval
- Medical Microbiology, University of Edinburgh Medical School, Teviot Place, Edinburgh EH8 9AG, Scotland, UK.
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De Fabo EC. Arctic stratospheric ozone depletion and increased UVB radiation: potential impacts to human health. Int J Circumpolar Health 2006; 64:509-22. [PMID: 16440613 DOI: 10.3402/ijch.v64i5.18032] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Contrary to popular belief, stratospheric ozone depletion, and the resultant increase in solar UV-B (280-320 nm), are unlikely to fully recover soon. Notwithstanding the success of the Montreal Protocol in reducing the amount of ozone destroying chemicals into the stratosphere, the life-times of these compounds are such that even with full compliance with the Protocol by all countries, it will be decades before stratospheric ozone could return to pre-1980 levels. This raises the question, therefore, of what will happen to biological processes essential to the maintenance of life on earth which are sensitive to damage by increased UV-B radiation, particularly those involved with human health? The polar regions, because of the vagaries of climate and weather, are the bellwether for stratospheric ozone depletion and will, therefore, be the first to experience impacts due to increases in solar UV-B radiation. The impacts of these are incompletely understood and cannot be predicted with certainty. While some UV-B impacts on human health are recognized, much is unknown, unclear and uncertain. Thus, this paper attempts, as a first approximation, to point out potential impacts to the health and welfare of human inhabitants of the Arctic due to increased solar UV-B radiation associated with stratospheric ozone depletion. As will be seen, much more data is critically needed before adequate risk assessment can occur.
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Affiliation(s)
- Edward C De Fabo
- The George Washington University, School of Public Health & Health Services, Laboratory of Photobiology & Photoimmunology, Washington, DC 20037, USA.
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Abstract
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.
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Affiliation(s)
- Mary Norval
- Medical Microbiology, University of Edinburgh Medical School, Edinburgh, United Kingdom.
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Silva E, Herrera L, Edwards AM, de la Fuente J, Lissi E. Enhancement of Riboflavin-mediated Photo-Oxidation of Glucose 6-phosphate Dehydrogenase by Urocanic Acid¶. Photochem Photobiol 2005. [DOI: 10.1562/2004-07-14-ra-233.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Tolleson WH. Human melanocyte biology, toxicology, and pathology. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2005; 23:105-61. [PMID: 16291526 DOI: 10.1080/10590500500234970] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The human melanocytes of the skin, hair, eyes, inner ears, and covering of the brain provide physiologic functions important in organ development and maintenance. Melanocytes develop from embryonic neural crest progenitors and share certain traits with other neural crest derivatives found in the adrenal medulla and peripheral nervous system. The distinctive metabolic feature of melanocytes is the synthesis of melanin pigments from tyrosine and cysteine precursors involving over 100 gene products. These complex biochemical mechanisms create inherent liabilities for melanocytic cells if intracellular systems necessary for compartmentalization, detoxification, or repair are compromised. Melanocyte disorders may involve pigmentation, sensory functions, autoimmunity, or malignancy. Environmental factors such as ultraviolet radiation and chemical exposures, combined with heritable traits, represent the principal hazards associated with melanocyte disorders.
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Affiliation(s)
- William H Tolleson
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA.
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