Infant Non-Secretor Histoblood Group Antigen Phenotype Reduces Susceptibility to Both Symptomatic and Asymptomatic Rotavirus Infection

Abstract

The infant non-secretor histoblood group antigen phenotype is associated with reduced risk of symptomatic rotavirus diarrhea, one of the leading global causes of severe pediatric diarrheal disease and mortality. However, little is known regarding the role of secretor status in asymptomatic rotavirus infections. Therefore, we performed a nested case-control study within a birth cohort study previously conducted in Dhaka, Bangladesh, to determine the association between infant secretor phenotype and the odds of asymptomatic rotavirus infection, in addition to the risk of rotavirus diarrhea, in unvaccinated infants. In the parent cohort, infants were enrolled in the first week of life and followed through the first two years of life with multiple clinic visits and active surveillance for diarrheal illness. Secretor phenotyping was performed on saliva. Eleven surveillance stools collected over the first year of life were tested for rotavirus by real-time RT-PCR, followed by conventional PCR and amplicon sequencing to identify the infecting P-type of positive specimens. Similar to findings for symptomatic diarrhea, infant non-secretors experienced significantly fewer primary episodes of asymptomatic rotavirus infection through the first year of life in a likely rotavirus P-genotype-dependent manner. These data suggest that non-secretors experienced reduced risk from rotavirus due to decreased susceptibility to infection rather than reduced infection severity.

Keywords: FUT2; diarrhea; gastroenteritis; histoblood group antigen; rotavirus; secretor.

Figure 1

Cumulative incidence of rotavirus infection in unvaccinated children through year 1 of life according to secretor phenotype. Cumulative incidence of (A) asymptomatic rotavirus infection in unvaccinated children who remained RV diarrhea-free through year 1 of life, and (B) any rotavirus infection (symptomatic RV diarrhea or asymptomatic infection) by each indicated time point. The numbers above each bar indicate the percentage of evaluable children with infection by that time point, along with the absolute number of children with infection by that time point in parentheses. * p < 0.05.