Pollen Grains Induce a Rapid and Biphasic Eczematous Immune Response in Atopic Eczema Patients

Abstract

Introduction: Eczematous reactions to type I allergy-inducing antigens are documented in a subgroup of patients with atopic eczema. Yet, the underlying immunological mechanisms are not well understood. Material and Methods: To delineate the effect of native pollen grains on human skin of healthy and atopic individuals we performed patch tests (atopy patch test with native pollen grains, PPT). Nickel patch tests (NPT) served as an established model of contact dermatitis. Skin site biopsies were taken 6–96 h after allergen application and investigated immunohistochemically. Results: Histology of positive patch tests showed an influx of mononuclear cells (predominantly CD4+, CD25+, CD45RO+). This influx was detected earlier in the PPT reaction than in the immune response to nickel. A biphasic cytokine response could be detected in the PPT: IL-5 dominated in the early, IFN-γ in the late phase. The NPT was continuously dominated by IFN-γ. Dendritic cell subpopulations imitated the earlier kinetics of the mononuclear infiltrate. Discussion: Thus, pollen grains induce eczematous reactions in susceptible individuals. This reaction appears clinically and immunohistochemically similar to the contact hypersensitivity reaction to nickel but follows a faster kinetic and a biphasic course: Th2 and IgE in the early (24 h) and Th1 predominance in the late (96 h) phase.

An update on the role of human dendritic cells in patients with atopic dermatitis

“…11 FcεRI 1 /CD123 1 /blood dendritic cell antigen 2-positive plasmacytoid dendritic cells (pDCs) are nearly absent from the epidermal skin of patients with AD 10,12 but are recruited to the dermis on allergen challenge. 13 LCs are assumed to be capable of maintaining the physiologic homeostasis of the skin. Both exogenous and endogenous danger signals increase, and epidermal LCs are supplemented by IDEC subtypes that are most likely recruited from the dermal compartment and precursor cells in the blood.…”

CD56highCD16−CD62L− NK Cells Accumulate in Allergic Contact Dermatitis and Contribute to the Expression of Allergic Responses

“…are abundantly expressed in acute ACD skin, and contribute to disease expression by enhancing the release of CXCR3 agonists induced by IFN-g (10), and by increasing ICAM-1 expression by keratinocyte, respectively (11). Although CD3 + T lymphocytes are the most prominent cellular type recruited in ACD skin, the inflammatory infiltrate also comprises of myeloid and plasmacytoid dendritic cells, as well as NK cells and NK-T lymphocytes (11)(12)(13)(14).…”

Prevention of Follicular Penetration: Barrier-Enhancing Formulations against the Penetration of Pollen Allergens into Hair Follicles

“…Eczematous reactions to type I allergy-inducing antigens are documented in a subgroup of patients with atopic eczema. It was demonstrated that pollen grains induce an inflammatory reaction in susceptible individuals with atopic eczema [24] . Ongoing investigations in Kiel and Hanover have shown that the atopic eczema is correlated with the pollution by birch pollen, with the symptoms becoming worse on those parts of the body which are not protected by textiles [25] .…”