For instance, children with reduced IgG responses to specific microbial antigens than healthy counterparts are prone to allergic diseases, including asthma, AD and FD.344,394,395 In studies of babies, higher AD risk had associations with reduced levels of Proteobacteria and elevated innate inflammatory response induced by TLR-4, and Ruminococcus decrease was associated with elevated TLR2-dependent innate inflammatory response.396–398 FA in early stage is also closely associated with reduced gut microbial abundance.344. Here, TLR4 is linked to Alzheimer disease.