Postnatal Development of Blood Group Antigens and Antibodies in the First Year of Life

Blood group antigens are biological markers in a large part of human tissues; therefore, their study is critical from the point of view of biomedicine. It is interesting to investigate the unique characteristics of antigen expression in the ABO system from an ontogenetic perspective. As previously stated, these antigens are carbohydrate-based. The full production of these antigens involves multiple stages, and their complete expression depends on specific stages of prenatal and postnatal development. Some researchers have revealed that they are weakly expressed in newborns, and group-specific antibodies are not found in the majority of studied newborns. Our current study is about the evaluation the qualitative and quantitative characteristics of the ABO system’s antigen and antibody expression in the first year of the postnatal period. A total of 202 Blood samples of infants aged 28 days to 12 months were used for the current study. Among them, there were 94 females (46.54±3.5%) and 108 males (53.46±3.5%). The materials were obtained from the M. Iashvili Batumi Maternal and Child Central Hospital. The main criterion for inclusion in the study was the age of the infants, in particular, the research samples were sorted into two groups: 1. from 28 days to 6 months (n=89) and; 2. from 6 months to 12 months (n=113). Qualitative and quantitative characteristics of group antigen antibodies were analyzed at the Immunogenetics Laboratory and Biosafety laboratories of the Batumi Shota Rustaveli State University. The research relied on the immunoserological method to visually detect agglutination reactions. Standard erythrocytes of groups A and B were used to detect group-specific antibodies, and anti-A, anti-B, and anti-D monoclonal antibodies were used to detect blood group A, B, and D antigens. In our research group, antigens of the ABO system are represented in the following order: O > A> B > AB, which corresponds to the population parameters of the mentioned region. 74.80±3.9% of the 202 studied infants carry the A antigen, with 41.57±3.4% belonging to the A(II) group (n=84) and 3.96±1.8% belonging to the AB (IV) group (n=8). It is important to note that we simultaneously screened subgroups of the A antigen within the A(II) and AB (IV) phenotypic groups. Around 52.17% (±5.2%) of infants with A(II) blood group phenotype carry the A1 subgroup (n=48), and about 39.13% (±5.0%) carry the A2 subgroup (n=36). In individuals with AB (IV) blood group phenotype, both the A1B subgroup and A2B subgroup were found to occur with equal frequency at approximately 4.35% (±2.1%). Since people with O (I) blood group have anti-A and anti-B antibodies in their plasma, we studied this characteristic in 91 newborns with O (I) blood group. Where, 38.46±5.0% of newborns had anti-A and anti-B antibodies (n=35), this indicator increased by 1.28 times in infants aged 28 days to 6 months, and by 1.93 times (approximately 2 times) in infants aged 6-12 months. We studied the peculiarities of the synthesis of antigens and antibodies of the ABO system during postnatal development. Based on the results it should be noted that the developmental profile of blood group antigens and antibodies for infants aged 6 to 12 months is very similar to that of adults compared to the newborn profile. However, in some circumstances, the specificity of ABO antigen and antibody detection in infants differs from that in adults. Based on our research data, we propose that reversed blood typing not be employed for joint screening of blood group antigen-antibodies in the above-mentioned age group, especially in newborns. We also suggested that A2 and A2B phenotypes were found by serology in the newborns. The postnatal period of development is required for the full expression of ABO system antigens. The A2 subgroup exhibits mimicry in the A1 subgroup serologically, which is a shifting trait in the following stage of ontogenesis. The Rh phenotypic manifestation is similar for newborns and of 6-12 age infants. A similar study should be planned in the next age group (2nd year of postnatal development) in order to determine when the complete synthesis of group antigen-antibodies occurs. It would also be interesting to conduct a similar study for other regions too. Because regions differ from each other based on climate, diet, and infections, which can influence group antigen antibody synthesis.