Association between O blood group and occurrence and severity of diarrhoea due to Escherichia coli.

During studies of diarrhoea due to Escherichia coli in 316 adult volunteers, ABO and Rh blood group determinations were done to look for differences in the occurrence or severity of illness in association with certain blood groups. In studies using heat-labile enterotoxin-producing E. coli, volunteers with O blood group had a significantly higher attack rate for diarrhoea than persons with other blood groups. In contrast, in studies with enteropathogenic or heat-stable enterotoxin-producing E. coli, no association was found between occurrence of diarrhoea and ABO group. These studies, and previous studies finding a similarly increased susceptibility to cholera in persons with O blood group, suggest that the mechanism of increased risk involves an interaction between blood group substances and the similar enterotoxin produced by E. coli and Vibrio cholerae.