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HLA-DR-positive cells in large plaque (atrophic) parapsoriasis
Journal of the American Academy of Dermatology
|October 1, 1981
Summary
HLA DR (Ia-like) antigens are not specific markers for B cells and monocytes. In large plaque parapsoriasis, T cells also express HLA DR, indicating activation and challenging diagnostic specificity.
Area of Science:
- Immunology
- Dermatopathology
Background:
- Monoclonal antibodies against HLA DR (Ia-like) antigens were initially thought to specifically identify B cells and monocytes.
- Large plaque parapsoriasis has been characterized as a T cell-mediated dermatosis.
Purpose of the Study:
- To investigate the expression of HLA DR antigens on T cells within cutaneous infiltrates in large plaque parapsoriasis.
- To evaluate the specificity of HLA DR as a marker for B cells and monocytes in pathological conditions.
Main Methods:
- Immunoperoxidase staining of serial tissue sections from two cases of large plaque parapsoriasis.
- Utilized a T cell antiserum, two monoclonal T cell antibodies, and a monoclonal antibody against HLA DR.
Main Results:
- T cells within the cutaneous infiltrates of large plaque parapsoriasis were found to be HLA DR-positive.
- This suggests that T cells in these cases were activated, as HLA DR positivity is associated with T cell activation.
Conclusions:
- HLA DR positivity is not exclusive to B cells and monocytes and can be expressed by activated T cells.
- Caution is advised when using HLA DR as a specific marker for B cells and monocytes in pathological specimens without concurrent T cell marker analysis.