Fig. 2.

Serial determinations of parameters for the first 72 days after the birth of the newborn. On day 19, less than 0.6 g/dL (0.4 mmol/L) of the total Hb 7.1 g/dL (4.3 mmol/L) was from endogenous E-positive RBCs. Only after 47 days, at a titer of anti-E below 4, did the E-positive RBCs survive and total Hb started to increase in parallel. Reticulocytes transiently decreased as a response to transfusions, and decreased again after day 61, when E-positive RBCs were being normalized. The newborn parameters were: anti-E titer determined by 2-step dilutions and analysis in CAT; total Hb (g/dL) from donor RBCs and newborn RBCs measured in a hematology analyzer; E-positive Hb was calculated as the E-positive RBC fraction of total RBCs measured by FC multiplied with the total Hb; reticulocytes were measured in a hematology analyzer. Informed consent was obtained from the parents of the infant. The study followed the guidelines of the institutional review board of Copenhagen University Hospital.