Malnourishment can alter the gut microbial composition and IgA responses, as demonstrated by the transfer of a malnourished infant’s IgA(+) bacterial consortium to gnotobiotic mice, which led to epithelial barrier disruption, weight loss, and sepsis, conditions preventable by administering IgA-targeted bacteria from healthy microbiota [39]. The gene discussed is CD79A; the disease is Sepsis.