The analyses focused on genes that have been implicated in malnutrition, such as cellular differentiation, barrier formation and function, and autophagy.21–23,66,67 Additionally, we examined SPIB as a marker of M cells, which are critical for the infection cycles of S. flexneri and other enteric pathogens like Salmonella and Yersinia. The gene discussed is SPIB; the disease is malnutrition.