Immunohistochemical analysis reveals CD163-negative, MPO-positive histiocytoid cells in multiple neutrophil-rich dermatoses, indicating they are not restricted to Sweet syndrome.
Key Points
To evaluate the expression of CD163 and myeloperoxidase (MPO) in mononuclear dermal infiltrate cells across different neutrophil-rich inflammatory dermatoses.
Applied a double immunostaining protocol using CD163 and MPO primary antibodies to skin biopsies across four neutrophil-rich conditions: Sweet syndrome, acute neutrophilic vasculitis, type 2 leprosy reaction, and sporotrichosis.
CD163+ MPO− macrophages were present in all four disease groups (<10% to >50% of positive cells), while CD163+ MPO+ macrophages ranged from <10% to 10%–50% across all groups.
CD163− MPO+ histiocytoid cells were detected in Sweet syndrome, type 2 leprosy reactions, and sporotrichosis, but were absent in acute neutrophilic vasculitis.