Pathogenicity of a disease-associated human IL-4 receptor allele in experimental asthma

Polymorphisms in the interleukin-4 receptor chain (IL-4R) have been linked to asthma incidence and severity, but a causal relationship has remained uncertain. In particular, a glutamine to arginine substitution at position 576 (Q576R) of IL-4R has been associated with severe asthma, especially in African Americans. We show that mice carrying the Q576R polymorphism exhibited intense allergen-induced airway inflammation and remodeling. The Q576R polymorphism did not affect proximal signal transducer and activator of transcription (STAT) 6 activation, but synergized with STAT6 in a gene target and tissue-specific manner to mediate heightened expression of a subset of IL-4 and IL-13responsive genes involved in allergic inflammation. Our findings indicate that the Q576R polymorphism directly promotes asthma in carrier populations by selectively augmenting IL-4Rdependent signaling.

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Tachdjian R, Mathias C, Al Khatib S, Bryce PJ, Kim HS, Blaeser F, O'Connor BD, Rzymkiewicz D, Chen A, Holtzman MJ, Hershey GK, Garn H, Harb H, Renz H, Oettgen HC, Chatila TA