Four-day high-fat diet primes persistent skin immune memory in mice, UCSF Nature study shows

The UCSF team switched lean mice to high-fat feed for four days then applied imiquimod cream, producing ear swelling comparable to chronically obese animals. After inflammation resolved and mice resumed low-fat diets, a second imiquimod challenge weeks later elicited amplified responses driven by resident memory T cells and rapid-response myeloid cells recruited during the brief dietary window. Parallel lung irritation experiments showed the same diet-triggered hyper-reactivity. These findings indicate that recent nutrient intake can rewire tissue-resident immunity faster than previously modeled in obesity-focused studies. Prior observational work linking Western diets to psoriasis and asthma flares (e.g., Nature Reviews Immunology 2023) lacked temporal resolution; this interventional design isolates the four-day window as sufficient for lasting priming. Human translation requires controlled feeding trials measuring recent dietary logs against inflammatory biomarkers. Next studies must test whether brief dietary reversal in patients with atopic dermatitis or psoriasis reduces flare severity within defined timeframes.