Supplementary Material for: Hemolytic Disease of the Fetus and Newborn due to an anti- LU1 (anti-Lua) alloantibody, case report

Many erythrocyte antibodies have been reported to cause hemolytic disease of the fetus and newborn (HDFN), but Lutheran (LU) alloantibodies are normally not involved in HDFN. Here we report the obstetrical history of a 29-year-old women with pregnancy complications due to an anti-LU1 antibody causing fetal anemia and the successful treatment with intrauterine transfusion (IUT). Non-immune hematological causes for fetal anemia and the presence of further alloantibodies, notably antibodies against low frequent antigens, could be ruled out. Swiss national immunohematology reference laboratory in Bern carried out a monocyte monolayer assay (MMA). The monocyte index (MI) was >20%, indicating the presence of a clinical relevant antibody. The diagnosis, acute management, and follow‐up of neonates with fetal anemia still represent an important area of activity for maternity/neonatal services. To our knowledge this is the first reported case of HDFN due to an anti-LU1 antibody requiring IUT.