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Photosensitive psoriasis--an immunohistochemical study after light provocation with UVA and UVB
1Department of Dermatology, Karolinska Hospital, Stockholm, Sweden.
Photo-Dermatology
|April 1, 1987
Summary
This study investigated photosensitive psoriasis by exposing patients to UV light. Researchers observed specific immune cell changes, particularly T-cells and monocytes, correlating with psoriasis development after UV exposure.
Area of Science:
- Dermatology
- Immunology
- Photobiology
Background:
- Photosensitive psoriasis involves lesion worsening after sun exposure.
- Polymorphous light eruption (PMLE) shares similarities with photosensitive psoriasis.
- Understanding the immune response to UV provocation is crucial for photosensitive psoriasis pathogenesis.
Purpose of the Study:
- To investigate the pathogenesis of photosensitive psoriasis.
- To analyze the cellular infiltrate in skin lesions following UV provocation.
- To compare immune responses in patients with and without a history of PMLE.
Main Methods:
- 21 patients with photosensitive psoriasis underwent UVA and UVB provocation.
- Skin biopsies were taken and immunophenotyped using monoclonal antibodies.
- Cellular infiltrate was analyzed, focusing on T-cell subsets, Langerhans cells, and monocytes.
Main Results:
- T-helper/inducer (Leu-3+) cells dominated the dermal infiltrate in most patients.
- T-cytotoxic/suppressor (Leu-2+) cells showed exocytosis in the epidermis after psoriasis developed.
- Increased Leu-M1+ cells (monocytes/granulocytes) were observed after psoriasis onset.
Conclusions:
- UV provocation can induce psoriasis development, sometimes following a PMLE-like reaction.
- Specific immune cell dynamics, including T-cell subsets and monocyte infiltration, characterize photosensitive psoriasis post-UV exposure.
- The findings provide insights into the immune mechanisms underlying UV-induced psoriasis flares.