Sunlight-Induced Immunosuppression in Humans Is Initially Because of UVB, Then UVA, Followed by Interactive Effects

Poon, Terence S. C.; Barnetson, R S; Halliday, Gary M.

doi:10.1111/j.0022-202x.2005.23894.x

Cited by 78 publications

(58 citation statements)

References 33 publications

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“…There seems to be some kind of dose relationship with different effects on different dose levels 47,48 and chronology of effects. 49 UV radiation activates similar immunological pathways to suppress the induction, or the elicitation, of the immune response. 50 As part of extra corporeal photopheresis UV-B modulates immunoresponse and is able to meliorate the clinical course of cutanous T-cell lymphoma.…”

Section: Biological Plausibilitymentioning

confidence: 99%

Sun exposure and malignant lymphoma: A population‐based case–control study in Germany

Weihkopf

Becker

Nieters

et al. 2007

Intl Journal of Cancer

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Although some causes for malignant lymphoma are known their etiology is not well understood so far. We analyze the relationship between sun exposure and malignant lymphoma in a multicenter, population-based case-control study. Patients with malignant lymphoma (n 5 710, 18-80 years) were prospectively recruited in 6 study regions in Germany. For each case, a gender, region and age-matched control was drawn from population-registers. In personal interviews, lifetime holidays spent in sunny climate, outdoor leisure activities and sunbed or sunlamp use were recorded. On basis of job task-specific supplementary questionnaires, an occupational physician assessed the cumulative working time outside. Odds ratios (OR) and 95%-confidence-intervals (CI) were calculated using conditional logistic regression analysis, adjusted for smoking and alcohol consumption. To increase statistical power, patients with specific lymphoma subentities were additionally compared with the entire control group using unconditional logistic regression. We observed a reduced overall lymphoma risk among subjects having spent vacations at sunny climates or frequently used sunbeds or sunlamps. The analysis of lymphoma subentities revealed similar results with the exception of T-NHL and follicular lymphoma which were positively associated with outdoor leisure activities. While cumulative working time outside appeared unrelated to NHL overall and most subentities, it was negatively associated with follicular lymphoma and weakly positively to HL. This data suggest that exposure to natural and artificial ultraviolet radiation may reduce the OR for lymphoma in this study population. ' 2007 Wiley-Liss, Inc.

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Section: Biological Plausibilitymentioning

confidence: 99%

Sun exposure and malignant lymphoma: A population‐based case–control study in Germany

Weihkopf

Becker

Nieters

et al. 2007

Intl Journal of Cancer

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“…1 An important feature of UVB exposure is the suppression of both primary and memory recall immune responses resulting in antigen-specific tolerance. 2 This study examined the cellular mechanisms of systemic UVB-induced immunosuppression, which is a phenomenon that can be observed when one skin site is exposed to UVB but antigen is applied at a distal, unirradiated site.…”

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confidence: 99%

Ultraviolet B Suppresses Immunity by Inhibiting Effector and Memory T Cells

Rana

Byrne

MacDonald

et al. 2008

The American Journal of Pathology

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Contact hypersensitivity is a T-cell-mediated response to a hapten. Exposing C57BL/6 mice to UV B radiation systemically suppresses both primary and secondary contact hypersensitivity responses. The effects of UVB on in vivo T-cell responses during UVB-induced immunosuppression are unknown. We show here that UVB exposure, before contact sensitization, inhibits the expansion of effector CD4؉ and CD8 ؉ T cells in skin-draining lymph nodes and reduces the number of CD4؉ and IFN-␥ ؉ CD8 ؉ T cells infiltrating challenged ear skin. In the absence of UVB, at 10 weeks after initial hapten exposure, the ear skin of sensitized mice was infiltrated by dermal effector memory CD8 ؉ T cells at the site of challenge. However, if mice were previously exposed to UVB, this cell population was absent, suggesting an impaired development of peripheral memory T cells. This finding occurred in the absence of UVB-induced regulatory CD4 ؉ T cells and did not involve prostaglandin E 2 , suggesting that the importance of these two factors in mediating or initiating UVB-induced immunosuppression is dependent on UVB dose. Together these data indicate that in vivo T-cell responses are prone to immunoregulation by UVB, including a novel effect on both the activated T-cell pool size and the development of memory T cells in peripheral compartments.

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“…Using a contact allergy model, it has been shown that there is moderate evidence of a positive interaction of UVB and UVA in human immunosuppression (Poon et al, 2005). Based on a human contact allergy model, the optimal wavelengths of the immunosuppressive action by UVB appear to be around 300 nm and for UVA around 370 nm.…”

Section: Immunosuppressionmentioning

confidence: 99%