Overexpression of helper T cell type 2-related molecules in the skin of patients with eosinophilic dermatosis of hematologic malignancy

Background: Eosinophilic dermatosis of hematologic malignancy (EDHM) is a rare dermatosis associated with blood tumors. Objective: To characterize the expression of T-cell and B-cell markers and pruritogenic mediators in EDHM skin. Methods: Immunohistochemical and immunofluorescence analysis were performed in 12 skin samples of EDHM, 11 samples of bullous pemphigoid (BP), and 5 samples from healthy controls (HC). Serum levels of interleukin (IL) 4 were analyzed in 11 patients with EDHM, 11 BP patients, and 5 HC by enzyme-linked immunosorbent assay. Results: T-cell markers, including clusters of differentiation (CD) 3, CD4, CD8, and CD5 were significantly overexpressed in EDHM and BP skin compared to HC. A predominance of CD4+ over CD8+ cells and GATA3+ (helper T cell type 2 [Th2] marker) over T-bet+ (Th1 marker) cells were observed. FOXP3 expression was increased but the FOXP3/CD4 ratio was low. B-cell markers were under-represented, without significant differences between the 3 groups. IL-4 and IL-31 were significantly overexpressed in EDHM and BP compared to HC and colocalized with the Th2-associated marker GATA3. Eotaxin-1 was significantly overexpressed in EDHM compared to BP and HC. IL-4 serum concentration was significantly increased in EDHM and BP compared to HC. Limitations: Small sample size; retrospective design. Conclusions: Targeting Th2-related molecules, in particular IL-4, holds promise for EDHM management.