Blood type A linked to more-severe diarrhea

Diarrhea associated with enterotoxigenic Escherichia coli (ETEC) infection is more severe among individuals with blood type A, based on data from 106 adults exposed to the agent.

The reseachers speculate that the increased severity is related, in part, to the presence of an adhesin molecule known as EtpA, which binds to the surface of the cells and combines with blood group A glycans to promote a more severe infection.

“Our studies suggest that the many ETEC strains that produce the EtpA adhesin may be particularly well equipped to preferentially infect hosts who express A blood group antigen on mucosal surfaces,” wrote Pardeep Kumar, MD, of Washington University, Saint Louis, and his colleagues.

ETEC, associated with choleralike illness, remains a major cause of infectious diarrhea in developing countries. No current vaccine offers significant protection against it, but EtpA may be useful in vaccine development. “More recently discovered virulence factors and an improved understanding of ETEC microbial pathogenesis could offer additional avenues to protect those at highest risk for severe disease and uncover novel molecular targets for future vaccine development,” the researchers said.

In a study published in the Journal of Clinical Investigation, the researchers examined blood samples from 106 adults who had participated in previous human infection model studies. The volunteers were challenged with an ETEC strain known as H10407 that was originally isolated from a case of choleralike illness.

Diarrhea was more frequent among A blood type individuals, compared with other types. Individuals with B or O blood types were significantly more likely to have no diarrhea or mild diarrhea after the E. coli challenge, compared with type A individuals (44% vs. 19%).

Overall, significantly more individuals with A or AB blood types developed moderate to severe diarrhea, compared with those with B or O blood types (81% vs. 56%). In addition, significantly more individuals with blood type A needed early initiation of antibiotic therapy, compared with those with B or O blood types (72% vs. 43%).

 

The study findings were limited by several factors, including the use of higher levels of bacteria to cause the infection than a typical exposure in nature. Also, the volunteers were treated with antibiotics once they met the criteria for severe diarrhea.

The researchers also noted that other blood group A lectins in addition to EtpA may not have been identified.

“While our recent studies have potentially important clinical and [vaccinological] implications, further study of the relationship between blood group, disease severity, and antigen expression could guide and inform use of these antigens in vaccines,” they wrote.

The study was supported by funds from the Enteric Vaccine Initiative of PATH, the Department of Veterans Affairs, the National Institutes of Health, and the Digestive Diseases Research Core Center at Washington University School of Medicine, St. Louis. The researchers had no financial conflicts to disclose.

SOURCE: Kumar P et al. J Clin Invest. 2018 May 17. doi: 10.1172/JCI97659.

Diarrhea associated with enterotoxigenic Escherichia coli (ETEC) infection is more severe among individuals with blood type A, based on data from 106 adults exposed to the agent.

The reseachers speculate that the increased severity is related, in part, to the presence of an adhesin molecule known as EtpA, which binds to the surface of the cells and combines with blood group A glycans to promote a more severe infection.

“Our studies suggest that the many ETEC strains that produce the EtpA adhesin may be particularly well equipped to preferentially infect hosts who express A blood group antigen on mucosal surfaces,” wrote Pardeep Kumar, MD, of Washington University, Saint Louis, and his colleagues.

ETEC, associated with choleralike illness, remains a major cause of infectious diarrhea in developing countries. No current vaccine offers significant protection against it, but EtpA may be useful in vaccine development. “More recently discovered virulence factors and an improved understanding of ETEC microbial pathogenesis could offer additional avenues to protect those at highest risk for severe disease and uncover novel molecular targets for future vaccine development,” the researchers said.

In a study published in the Journal of Clinical Investigation, the researchers examined blood samples from 106 adults who had participated in previous human infection model studies. The volunteers were challenged with an ETEC strain known as H10407 that was originally isolated from a case of choleralike illness.

Diarrhea was more frequent among A blood type individuals, compared with other types. Individuals with B or O blood types were significantly more likely to have no diarrhea or mild diarrhea after the E. coli challenge, compared with type A individuals (44% vs. 19%).

Overall, significantly more individuals with A or AB blood types developed moderate to severe diarrhea, compared with those with B or O blood types (81% vs. 56%). In addition, significantly more individuals with blood type A needed early initiation of antibiotic therapy, compared with those with B or O blood types (72% vs. 43%).

 

The study findings were limited by several factors, including the use of higher levels of bacteria to cause the infection than a typical exposure in nature. Also, the volunteers were treated with antibiotics once they met the criteria for severe diarrhea.

The researchers also noted that other blood group A lectins in addition to EtpA may not have been identified.

“While our recent studies have potentially important clinical and [vaccinological] implications, further study of the relationship between blood group, disease severity, and antigen expression could guide and inform use of these antigens in vaccines,” they wrote.

The study was supported by funds from the Enteric Vaccine Initiative of PATH, the Department of Veterans Affairs, the National Institutes of Health, and the Digestive Diseases Research Core Center at Washington University School of Medicine, St. Louis. The researchers had no financial conflicts to disclose.

SOURCE: Kumar P et al. J Clin Invest. 2018 May 17. doi: 10.1172/JCI97659.

Diarrhea associated with enterotoxigenic Escherichia coli (ETEC) infection is more severe among individuals with blood type A, based on data from 106 adults exposed to the agent.

The reseachers speculate that the increased severity is related, in part, to the presence of an adhesin molecule known as EtpA, which binds to the surface of the cells and combines with blood group A glycans to promote a more severe infection.

“Our studies suggest that the many ETEC strains that produce the EtpA adhesin may be particularly well equipped to preferentially infect hosts who express A blood group antigen on mucosal surfaces,” wrote Pardeep Kumar, MD, of Washington University, Saint Louis, and his colleagues.

ETEC, associated with choleralike illness, remains a major cause of infectious diarrhea in developing countries. No current vaccine offers significant protection against it, but EtpA may be useful in vaccine development. “More recently discovered virulence factors and an improved understanding of ETEC microbial pathogenesis could offer additional avenues to protect those at highest risk for severe disease and uncover novel molecular targets for future vaccine development,” the researchers said.

In a study published in the Journal of Clinical Investigation, the researchers examined blood samples from 106 adults who had participated in previous human infection model studies. The volunteers were challenged with an ETEC strain known as H10407 that was originally isolated from a case of choleralike illness.

Diarrhea was more frequent among A blood type individuals, compared with other types. Individuals with B or O blood types were significantly more likely to have no diarrhea or mild diarrhea after the E. coli challenge, compared with type A individuals (44% vs. 19%).

Overall, significantly more individuals with A or AB blood types developed moderate to severe diarrhea, compared with those with B or O blood types (81% vs. 56%). In addition, significantly more individuals with blood type A needed early initiation of antibiotic therapy, compared with those with B or O blood types (72% vs. 43%).

 

The study findings were limited by several factors, including the use of higher levels of bacteria to cause the infection than a typical exposure in nature. Also, the volunteers were treated with antibiotics once they met the criteria for severe diarrhea.

The researchers also noted that other blood group A lectins in addition to EtpA may not have been identified.

“While our recent studies have potentially important clinical and [vaccinological] implications, further study of the relationship between blood group, disease severity, and antigen expression could guide and inform use of these antigens in vaccines,” they wrote.

The study was supported by funds from the Enteric Vaccine Initiative of PATH, the Department of Veterans Affairs, the National Institutes of Health, and the Digestive Diseases Research Core Center at Washington University School of Medicine, St. Louis. The researchers had no financial conflicts to disclose.

SOURCE: Kumar P et al. J Clin Invest. 2018 May 17. doi: 10.1172/JCI97659.