Blood group phenotyping and associated sepsis across childhood stages: A case-control study

Variations in blood group antigens may influence susceptibility to infections, as certain antigens can act as microbial receptors. Sepsis remains a major cause of morbidity and mortality in pediatric populations; however, the relationship between blood group phenotypes and infection risk is not fully elucidated. This study aimed to investigate the association between blood group phenotypes and sepsis across different pediatric age groups. A case-control study was conducted involving 302 pediatric patients, including 60 with sepsis (cases) and 242 with non-septic illnesses (controls). Blood group phenotyping (ABO, Rh, Kell), complete blood count, blood cultures, and antimicrobial susceptibility testing for culture-positive samples were performed. The mean age of participants was 2.59 ± 2.07 years, comprising 22 newborns (7%), 118 infants (39%), and 162 children (54%). Among sepsis cases, the mean age was 1.78 ± 1.58 years, with 48.3% being male. In the control group, the mean age was 2.15 ± 2.78 years, and 59.5% were male. Blood group O was the most prevalent (55.3%), followed by A (24.8%), B (15.6%), and AB (4.3%). The most frequently isolated pathogens were Gram-positive cocci (45%), followed by Gram-negative bacilli (31.6%), Candida species (13.3%), and mixed infections (10%). A statistically significant association was observed between the AB blood group and susceptibility to specific microorganisms, particularly Gram-negative bacilli and multidrug-resistant (MDR) strains. This study highlights a significant association between the AB blood group and increased susceptibility to certain pathogens in pediatric sepsis. These findings warrant further large-scale investigations to better define the role of blood group phenotypes in infection risk among children.