Effects of PUVA on delayed hypersensitivity in the guinea-pig

Austad, J; Mørk, Nils‐Jørgen

doi:10.1111/j.1365-2133.1981.tb00973.x

Cited by 12 publications

(3 citation statements)

References 14 publications

(7 reference statements)

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“…UV-induced T-cell suppression can explain our previous findings in guinea pigs when sensitized animals exposed to UV radiation showed a reduced response to an elicitation dose of antigen applied on non-irradiated skin [4]. Pretreatment of mice with high doses of UV radiation has also been shown to induce a systemic inability to develop contact hypersensitivity to antigen applied after radiation [15].…”

Section: Discussionmentioning

confidence: 77%

“…Ultraviolet radiation has been shown to modify cutaneous immune responses both in animal species and in humans. We have earlier reported that psoralens plus UVA (PUVA), UVB, and UVC all reduce the contact allergic response in previously sensitized guinea pigs when the animals were challenged with antigen after radiation [3][4][5]. Langerhans cells (LC) play a crucial role as accessory cells in the induction of the antigen-specific T-cell response in contact allergy [7].…”

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confidence: 99%

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Effect of UVB on Alloactivating and Antigen Presenting Capacity of Human Epidermal Langerhans Cells

Austad

Braathen

1985

Scand J Immunol

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Human epidermal cell suspensions (EC) were obtained by the suction blister technique and enzyme digestion. EC were irradiated in microtitre plates with doses up to 510 mJ/cm2 (2.6 minimal erythemal dose (MED] by means of fluorescent light bulbs emitting a 280-320 nm continuous spectrum with a peak at 310 nm. Purified allogeneic T cells were added to the EC immediately or 24 h after radiation. Irradiated EC were pulsed with purified protein derivative (PPD) for 90 min immediately or 24 h after radiation and then cocultured with purified autologous T cells. PPD-pulsed EC were also irradiated before being cocultured with autologous T cells. Pretreatment of EC suspensions with anti-DR antiserum plus complement abolished both the alloactivating and the antigen-presenting capacity, indicating that the DR-positive Langerhans cells are mainly responsible for these functions. There were no differences in the number of DR-positive cells in EC before or immediately after radiation. A statistically significant and UV-dose-dependent reduction of the alloactivating ability of EC was found both when allogeneic T cells were added immediately and when they were added 24 h after radiation. Likewise, a significant and dose-dependent reduction of the PPD-specific T-cell response was obtained in cultures when using irradiated EC that were PPD-pulsed immediately or 24 h after radiation. EC that were first PPD-pulsed and then irradiated induced a significantly increased T-cell response after low UV doses (1 or 2 MED), whereas higher doses induced a significant reduction of the T-cell responses.

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Section: Discussionmentioning

confidence: 77%

mentioning

confidence: 99%

Effect of UVB on Alloactivating and Antigen Presenting Capacity of Human Epidermal Langerhans Cells

Austad

Braathen

1985

Scand J Immunol

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“…This result may be explained by a decreased density of LC (Streilein et al, t98oa, b;Noonan, Pederson & Kripke, 1980) or by changes in their structure (Stingl et al, 1980). Exposure to UV light inhibits contact sensitivity in mice (Noonan, Pederson & Kripke, 1980) guinea-pigs (Morison et al, 19^1;Austad & Mork, 1981) and humans (O'Dell et al, 1980;Strauss, Bridges & Greaves, 1980). Possibly LC deficiency permits antigen to enter the epidermis without recognition (Bergstresser,Toews & Streilein,t98o) and allows the development of antigen-specific T suppressor lymphocytes (Horio & Okamoto, 1983).…”

Section: Discussionmentioning

confidence: 99%

PUVA therapy prevents sensitization to mechlorethamine in patients with psoriasis

1985

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Two groups of 20 patients with psoriasis were treated with mechlorethamine applied topically (group A) or with PUVA combined with mechlorethamine (group B). In group B mechlorethamine was started after six PUVA treatments.Results showed a significant decrease of the incidence of contact dermatitis in group B (30%) compared with group A (75%). Allergic dermatitis, demonstrated by a positive patch test to mechlorethaniine with an histology of eczema, was observed in 55% of patients in group A and 20% in group B. The incidence of irritant dermatitis was not significantly different in the two groups. Allergic dermatitis was observed later in group B: after an average of 32 2 applications of mechlorethamine compared with 25 applications in group A.Possible mechanisms responsible for these results are reduction of epidermal Langerhans cells by PUVA therapy and induction of antigen-specific suppressor T cells.Patients living far from a specialized centre might be treated initially with PUVA therapy then with mechlorethamine alone, at home. This schedule may reduce the incidence of contact dermatitis to mechlorethamine.Correspondence: Pr. J.Thivolet.

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Mutagenicity and Carcinogenicity of Methoxsalen Plus UV-A

Roelandts¹

1984

Arch Dermatol

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Effects of PUVA on delayed hypersensitivity in the guinea-pig

Cited by 12 publications

References 14 publications

Effect of UVB on Alloactivating and Antigen Presenting Capacity of Human Epidermal Langerhans Cells

Effect of UVB on Alloactivating and Antigen Presenting Capacity of Human Epidermal Langerhans Cells

PUVA therapy prevents sensitization to mechlorethamine in patients with psoriasis

Mutagenicity and Carcinogenicity of Methoxsalen Plus UV-A

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