Effect of Phototherapy and Urocanic Acid Isomers on Natural Killer Cell Function

Gilmour, Jill; Vestey, J.P.; George, S.; Norval, Mary

doi:10.1111/1523-1747.ep12363652

Cited by 77 publications

(65 citation statements)

References 41 publications

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“…Although it has been shown that PUVA treatment reduces the functional capacity of epidermal T lymphocytes and NK activity [28, 29], the percentages of circulating T and NK cell subsets were not affected by PUVA treatment [30]. The data of this study show, however, that PUVA treatment interferes with the physiological response to acute stress, in particular NK cell circulation.…”

Section: Discussioncontrasting

confidence: 62%

Stress-Induced Endocrine and Immunological Changes in Psoriasis Patients and Healthy Controls

Schmid-Ott

Jacobs²,

Jäger

et al. 1998

Psychother Psychosom

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Background: Clinical observations suggest that psychological stress can induce exacerbation of psoriasis. It is hypothesized that these stress effects on the course and outcome of psoriasis are caused by neuroendocrine modulation of immune functions. Therefore we investigated the cardiovascular, endocrine and immunological response to a laboratory stressor in psoriasis patients and healthy controls. Methods: Untreated (n = 7) and PUVA-treated (n = 4) psoriatics and healthy controls (n = 7) were exposed to a brief laboratory stressor (public speaking and mental arithmetic). Heart rate and blood pressure, catecholamine, cortisol, and DHEA plasma concentration, as well as distribution of T and NK lymphocytes were analyzed before, immediately after and 1 h after stress exposure. Results: Heart rate and blood pressure increased in all three groups during stress exposure with the most pronounced changes in PUVA-treated patients. Psoriasis patients displayed higher adrenaline values but diminished cortisol and DHEA plasma concentrations compared to controls. NK cell numbers (CD16⁺, CD56⁺), but not T lymphocyte subsets, increased immediately after stress exposure in untreated patients and controls. This effect was significantly diminished in PUVA-treated patients. Conclusions: The data of this pilot study indicate an enhanced stress-induced autonomic response and diminished pituitary-adrenal activity in psoriasis patients. PUVA treatment seems to interfere with the cardiovascular and NK cell response to acute psychological stress. Future studies will analyze the stress-induced neuroimmunological mechanisms in psoriatics in more detail.

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Section: Discussioncontrasting

confidence: 62%

Stress-Induced Endocrine and Immunological Changes in Psoriasis Patients and Healthy Controls

Schmid-Ott

Jacobs²,

Jäger

et al. 1998

Psychother Psychosom

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“…Some models could also be used to compose a factor for intraspecies variation (IAV; between different human subjects). Figure 1 illustrates the paradigm used for human dose-response assessment by extrapolation from animal data (13)(14)(15)(16)(17)(18)(19)(20) …”

Section: Methodsmentioning

confidence: 99%

Risk assessment for the harmful effects of UVB radiation on the immunological resistance to infectious diseases.

Goettsch

Garssen

Slob

et al. 1998

Environ Health Perspect

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Risk assessment comprises four steps: hazard identification, dose-response assessment, exposure assessment, and risk charcterization. In this study, the effects of increased ultraviolet B (UVB, 280-315 nm) radiation on immune fiuctions and the immunological resistance to infectious diseases in rats were analyzed according to this strategy. In a parallelogram approach, nonthreshold mathematical methods were used to esismate the risk for the human population after increasd exposure to UVB radiation. These data demontrate, using a worst-case strategy (sensitive individuals, no Risk assessment is a process of analyzing relevant biological, dose-response, and exposure data for a particular agent in an attempt to establish qualitative and quantitative estimates of adverse effects on human health (1). As defined by the frequently cited National Academy of Science Report (2), risk assessment comprises four steps: hazard identification, dose-response assessment, exposure assessment, and risk characterization. This general framework covers the process of assessing risk of cancer as well as noncancer endpoints, including decreased resistance to infections. The present study is not aimed at the determination or calculation of the maximal tolerable dose of UV radiation humans are advised or allowed to be exposed to. This study only serves as an estimation of the effect of exposure to increased levels of UVB with respect to the immune system and related resistance to infections in comparison to humans that are not exposed to increased UVB levels due to ozone depletion.The first step, hazard identification, involves a largely qualitative evaluation of available human and animal data to determine whether a chemical or physical agent is a potential hazard. Consideration is given to the dose, route, and duration of exposure in the test species. Any possible change in immune function, due to the agent studied, indicates that this agent is a potential hazard. Many studies indicate that suberythemal doses of ultraviolet light can affect the immune system in rodents as well as in humans. The major effect of UV exposure is suppression of the cellular immune system and of natural killer cell (NK) function, which is found in humans as well as in rodents. In rodent studies it has been demonstrated that UV-induced immunomodulation can lead to a lowered resistance to certain infections and tumors (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17).Following hazard identification, doseresponse studies (step 2 of risk assessment)give quantitative information, which is the basis for obtaining the no-observed adverse effect level (NOAEL) and the lowest adverse effect level (LOAEL), which are threshold values. This information is also necessary to determine the effective dose, which induces a certain level of suppression of an immune function, e.g., 50% suppression (ED50), for which it is assumed that there is no threshold dose value. The ED50, the dose that inhibits the response by 50%, can be calculated using linear or nonlinear regressio...

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“…In brief, the NK cell activity of human peripheral blood mononuclear cells was inhibited by 10-2-10-4 M cis-UCA while trans-UCA at the same concentration had no effect (26). However another study, in which the mononuclear cells were depleted of dendritic cells and monocytes before the assay, showed the reverse with trans-UCA inhibiting the NK activity and cis-UCA having no effect (27).…”

Section: Effects Of Uca In Vih0mentioning

confidence: 97%

“…Recently, it was shown that cis-UCA does not directly affect cAMP production in these cells but acts by inhibiting prostaglandin El-induced cAMP synthesis (36). In an entirely different cell type, the NK cells, it has been speculated that cis-UCA may suppress NK cell activity by elevating cAMP levels intracellularly (26).…”

Section: Mode(s) Of Action Of Ucamentioning

confidence: 99%

Chromophore for UV‐lnduced Immunosuppression: Urocanic Acid

Norval

1996

Photochem & Photobiology

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Effect of Phototherapy and Urocanic Acid Isomers on Natural Killer Cell Function

Cited by 77 publications

References 41 publications

Stress-Induced Endocrine and Immunological Changes in Psoriasis Patients and Healthy Controls

Stress-Induced Endocrine and Immunological Changes in Psoriasis Patients and Healthy Controls

Risk assessment for the harmful effects of UVB radiation on the immunological resistance to infectious diseases.

Chromophore for UV‐lnduced Immunosuppression: Urocanic Acid

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