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The cell-components and cytokines in the subcorneal microabscess of psoriasis
Abstract:
Munro's microabscess of psoriasis has been generally considered to be composed of polymorphonuclear neutrophils (PMNs). However, the cell-components of the microabscess has not been fully clarified. To identify the presence of mononuclear cells (MNCs) in Munro's microabscess and the subcorneal pustule of pustular psoriasis, we observed psoriatic lesions histologically and immunohistologically. Morphologically a few MNCs were found among PMNs and they seemed to include Langerhans cells (CD1a+), helper/inducer T cells (CD4+, CD5+), and macrophages (CD14+) which expressed HLA-DR. Some of them seemed to produce gamma-interferon (IFN-gamma), interleukin 6 (IL-6) and IL-8. The keratinocytes surrounding the microabscess also had IL-8 and some epidermal cells of the proliferated epidermal papillae also expressed IL-6 and IL-8 in psoriatic lesions. The production of IL-6 and IL-8 is considered to effect both chemotaxis and the proliferation of epidermal cells. The presence of these cytokines also suggests that MNCs exist in Munro's microabscess and that they might contribute to the microabscess formation of psoriatic lesions.
Insights
Monro's microabscess in psoriasis contains mononuclear cells (MNCs) alongside neutrophils. These MNCs, including macrophages and T cells, may contribute to microabscess formation by producing key cytokines.
Area of Science:
- Dermatology
- Immunology
- Histopathology
Background:
- Munro's microabscess in psoriasis is traditionally viewed as solely composed of polymorphonuclear neutrophils (PMNs).
- The precise cellular composition of these microabscesses remains incompletely understood.
Purpose of the Study:
- To investigate the presence and types of mononuclear cells (MNCs) within Munro's microabscesses and subcorneal pustules in psoriatic lesions.
- To explore the potential role of MNCs and associated cytokines in the pathogenesis of psoriasis.
Main Methods:
- Histological and immunohistological examination of psoriatic lesions.
- Identification of cell markers including CD1a, CD4, CD5, CD14, and HLA-DR.
- Detection of cytokine production, specifically gamma-interferon (IFN-γ), interleukin-6 (IL-6), and interleukin-8 (IL-8).
Main Results:
- Mononuclear cells (MNCs), including Langerhans cells, helper T cells, and macrophages, were identified within Munro's microabscesses among PMNs.
- These MNCs expressed HLA-DR and appeared to produce IFN-γ, IL-6, and IL-8.
- Keratinocytes surrounding the microabscess and epidermal cells in proliferated papillae also expressed IL-8 and IL-6.
Conclusions:
- Mononuclear cells are present in Munro's microabscesses and subcorneal pustules of psoriasis.
- MNCs and their produced cytokines (IL-6, IL-8) likely play a role in the chemotaxis of inflammatory cells and epidermal proliferation, contributing to microabscess formation in psoriasis.