Investigation of ABO natural antibodies in neonates

MATTALONI, STELLA MARIS; ENSINCK, MARÍA ALEJANDRA; LUJÁN BRAJOVICH, MELINA ELIANA; TRUCCO BOGGIONE, CAROLINA; RACCA, LILIANA; BIONDI, CLAUDIA; COTORRUELO, CARLOS

Los cocos, Córdoba

Congreso; LXI Reunión Anual de la Sociedad Argentina de Inmunología; 2013

Sociedad Argentina de Inmunología

ABO anti-A and anti-B IgM antibodies are not detected in cord serum by hemagglutination methods. The appearance of these isohemagglutinins regularly and naturally in all healthy individuals after a one year of age has been attributed to the immaturity of B1 cells in the newborn. The aim of this study was to investigate the presence of anti-A IgM antibodies in O blood group neonates using flow cytometry. Serum samples obtained from umbilical cord of blood group O newborns (n = 25) were incubated with 0.2% red blood cell (RBC) suspensions from group O (negative control) and group A adult normal volunteer donors. After washing with phosphate-buffered saline (PBS), samples were labeled with anti-IgM conjugated to APC for 30 minutes at RT in the dark, washed with PBS and resuspended in sheat fluid. Samples were acquired on a FACSAria II cytometer. Two hundred thousand events were evaluated in duplicate for each sample and data were analyzed with the FACSDiva software. The RBC population was selected based on its characteristics of FSC (cell size) versus SSC (cell density). The percentage (%) values of RBCs with bound IgM for A RBCs and O RBCs, expressed as mean ± standard deviation were 0.72% ± 1.67% and 0.11% ± 0.04%, respectively. The results obtained showed a significant increase (p