CCL22 and Alzheimer disease: Treatment with Bifidobacteria adolescentis alleviated the AD‐like clinical symptoms, decreased serum IgE levels, suppressed IL‐4, IL‐5, IL‐13, and CCL22 levels, and increased interferon‐γ and IL‐10 levels, thus promoting Th1‐type and suppressing Th2‐type immune responses.24