Mast cells, Mast/Stem Cell Growth Factor receptor (c-kit/cd117) and IgE may be integral to the pathogenesis of endemic pemphigus foliaceus



Introduction: Pemphigus foliaceus (PF) is endemic in some South American countries, especially in Colombia and Brazil; in Brazil, it is also known as fogo selvagem (FS). We aimed to study the presence of mast cells and the expression of the mast/stem cell growth factor receptor (c-kit/CD117) in PF skin biopsies, as well as the role of IgE in the disease pathogenesis.
Methods: Forty-four skin biopsies from patients affected by endemic PF (EPF) (30 patients from El Bagre, Colombia, and 14 from the northeastern region of São Paulo State, Brazil), 48 control biopsies from Colombian and Brazilian endemic areas, and additional control biopsies from none endemic areas in Colombia and the USA non were studied. Immunohistochemistry (IHC) was performed to evaluate skin biopsies with anti-mast cell tryptase (MCT), anti-c-kit and anti-IgE antibodies. We also searched for serum IgE in 30 EPF and 30 non-atopic controls from the El Bagre region via ELISA. In our El Bagre patients and controls, we also searched for IgE in skin samples by direct immunofluorescence.
Results: In 100% of the EPF biopsies, MCT, c-kit and IgE were identified with stronger expression relative to control biopsies, especially in the inflammatory infiltrates around upper dermal blood vessels and dermal eccrine glands. IgE staining was positive along the BMZ in some EPF skin samples. The DIF results confirmed a linear deposition of IgE at the BMZ. Increased IgE serum levels were also noted in PF patients relative to controls..
Conclusions: In patients with EPF, the observed increased expression of MCT, c-kit and IgE in lesional skin, associated with higher serum IgE levels may indicate possible IgE participation in the antigenic response.

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