929:
Type 2 Innate Lymphoid Cells and Eosinophil Progenitor Cells are Preferentially Increased in Lesional Skin of Subjects with Atopic Dermatitis
Monday, March 5, 2018: 3:00 PM
S230AB (Convention Center)
Sai Sakktee Krisna, BSc, , , , , , , , ,
RATIONALE:

Atopic dermatitis (AD) is characterized by chronic puritic relapsing eczematous lesions of the skin. Eosinophilic inflammation in AD is orchestrated by activation of type 2 inflammatory cells including CD4+ T cells and type 2 innate lymphoid cells (ILC2). We propose that recruitment and differentiation of eosinophil progenitor cells (EoP) contributes to the local expansion of eosinophils in AD lesional skin. This study aimed to quantify total and type 2 cytokine producing levels of ILC2, EoP and CD4+ T cells in AD.

METHODS:

In a cross-sectional study of moderate-to-severe AD subjects (n=6), pro-inflammatory cells were enumerated in blood and from excised skin lesions taken after an 8 day washout of systemic steroids. By flow cytometry, live, singlet CD45+cells were identified as EoP (CD34+125+), ILC2 (lin-CD127+CD294+), CD4+ T cells (Lin+CD3+CD4+). Data expressed as percent of total CD45+ cells. Cross-compartmental comparisons were made using Wilcoxon rank-sum test.

RESULTS:

As a proportion of total leukocytes, there were greater levels of ILC2 (0.012% vs 0.002%, p=0.031) in excised skin lesions compared to blood. A similar trend was observed with EoP (0.045% vs 0.002%, p=0.094). In addition, IL-5 and IL-13 producing ILC2 and EoP reflected a higher percentage in the skin compared to peripheral blood. Conversely, there were greater proportion of CD4+ T cells in blood compared to skin of AD subjects (38.170% vs 1.357%, p=0.03).

CONCLUSIONS:

The current data suggests that preferential expansion of skin-resident ILC2 may provide the type 2 cytokines that recruit and drive localized differentiation of EoP into mature eosinophils in AD lesions.