The Association between Symptomatic Rotavirus Infection and Histo-Blood Group Antigens in Young Children with Diarrhea in Pretoria, South Africa

Lewis a-b- histo-blood group antigen phenotype is predictive of severe COVID-19 in the black South African population group

Several risk factors have been associated with SARS-CoV-2 infections and severity of COVID-19 disease it causes. This study investigated whether variations in histo-blood group antigen (HBGA) expression can predispose individuals to SARS-CoV-2 infections and severity of the disease. Nasopharyngeal swabs, randomly selected from SARS-CoV-2 positive and SARS-CoV-2 negative individuals, were tested for Lewis and H-type 1 HBGA phenotypes by ELISA using monoclonal antibodies specific to Lewis a, Lewis b and H type 1 antigens. The most common Lewis HBGA phenotype among all study participants was Lewis a-b+ (46%), followed by Lewis a-b- (24%), Lewis a+b- and Lewis a+b+ (15% each), while 55% of the study participants were H-type 1. Although SARS-CoV-2 negative individuals had a lower likelihood of having a Lewis a-b- phenotype compared to their SARS-CoV-2 positives counterparts (OR: 0.53, 95% C.I: 0.255-1.113), it did not reach statistical significance (P = 0.055). The frequency of Lewis a+b+, Lewis a+B-, Lewis a-b+, H type 1 positive and H type 1 negative were consistent between SARS-CoV-2 positive and SARS-CoV-2 negative individuals. When stratified according to severity of the disease, individuals with Lewis a+b- phenotype had a higher likelihood of developing mild COVID-19 symptoms (OR: 3.27, 95% CI; 0.9604-11.1), but was not statistically significant (P = 0.055), while Lewis a-b- phenotype was predictive of severe COVID-19 symptoms (OR: 4.3, 95% CI: 1.274-14.81), P = 0.016. In conclusion, individuals with Lewis a-b- phenotype were less likely to be infected by SARS-CoV-2, but when infected, they were at risk of severe COVID-19.

Intestinal mucin-type O-glycans: the major players in the host-bacteria-rotavirus interactions

Rotavirus (RV) causes severe diarrhea in young children and animals worldwide. Several glycans terminating in sialic acids (SAs) and histo-blood group antigens (HBGAs) on intestinal epithelial cell (IEC) surface have been recognized to act as attachment sites for RV. IECs are protected by the double layer of mucus of which O-glycans (including HBGAs and SAs) are a major organic component. Luminal mucins, as well as bacterial glycans, can act as decoy molecules removing RV particles from the gut. The composition of the intestinal mucus is regulated by complex O-glycan-specific interactions among the gut microbiota, RV and the host. In this review, we highlight O-glycan-mediated interactions within the intestinal lumen prior to RV attachment to IECs. A better understanding of the role of mucus is essential for the development of alternative therapeutic tools including the use of pre- and probiotics to control RV infection.