Jornal de Imunologia Clínica e Celular
Acesso livre

Abstrato

Innate Immune Regulation of the Allergic March: Using House Dust to Validate the Hygiene Hypothesis

Anthony A Horner

Over the last several decades, it has become increasingly clear that innate immune responses to microbes are mediated by several families of pattern recognition receptors (PRRs) constitutively expressed by a wide range of hematopoietic and non-hematopoietic cell types. These receptors respond to molecules and enzymatic byproducts generated by fungi, parasites, bacteria, and viruses that are often referred to as microbe associated molecular patterns (MAMPs). Not unexpectedly, my laboratory has found that PRRs also play a dominant role in innate responses to non-infectious immunostimulatory materials present in house dust extracts (HDEs) and the living environments they represent. However, our investigations challenge the commonly held view that microbial products in ambient air protect against the allergic march by promoting protective Th1 biased adaptive responses to inspired aeroallergens. Instead, all HDEs studied to date have preferentially promoted the development of Th2 biased airway hypersensitivities when used as adjuvants for intranasal (i.n.) vaccination of mice. In contrast, daily low dose i.n. HDE delivery was found to promote the development of aeroallergen tolerance. This article will review these experimental findings as evidence to propose a new paradigm by which airborne MAMPs and other stimulants of innate immunity may influence aeroallergen specific immunity and the genesis of allergic respiratory diseases.