Abstract
Twenty preterm and term female neonates were exchange-transfused with males donor fresh blood during their first days of life because of hyperbilirubinaemia or severe septicaemia. In order to study the presence of donor lymphocytes in the neonates peripheral blood, chromosome studies were performed immediately after,12 and 72 hours following the exchange transfusion. We used the fluorescent-binding technique in order to distinguish the donor's cells by the presence of the γ-chromosone or other fluorescent markers in at least 300 mitotic figures in each speciment. We found that in jaundiced babies immediately following exchange transfusion less than 10% of the lymphocytes came from the donor and 12 hours later only 1-2% were still present.However in neonates exchange-transfusion for septicaemia the percentage of donor's lymphocytes immediately following the proceedure sometimes reached 50% and dropped to less than 10% by 12 hours.This shows the inability of the depressed by the infection host defence mechanisms of the newborn to deal with the donor's lymphocytes.