HEMOLYTIC-DISEASE OF THE NEWBORN DUE TO THE SCIANNA ANTIBODY, ANTI-SC2

Background: Alloantibodies to the low-frequency antigen Scianna 2 (Sc2 ) are uncommon and not previously reported to cause immune hemolysis. Case Report: A group B, Rh-negative infant born to a group B, Rh-posit ive mother had a 2+ direct antiglobulin test, as well as modest hyperb ilirubinemia and a hematocrit of 45 percent. Ongoing immune hemolysis led to a hematocrit of 17.3 percent on Day 20 of life, and the infant required hospitalization and red cell transfusions. The routine matern al antibody screen was negative, but anti-Sc2 was detected during work -up for a low-frequency red cell antigen, and the father's red cells t yped as Sc:1,2. Conclusion: Anti-Sc2 can cause clinically significant hemolytic disease of the newborn. Although the antibody is uncommon, i ts frequency and hemolytic potential may be underappreciated, in part because investigations often are not carried out in the infant whose r ed cells are ABO-incompatible with maternal blood.