Prognostic factors and management in pregnancies complicated with severe Kell alloimmunization: Experiences of the last 13 years

Because of the recent referral of an anti-Kell sensitized pregnant woman, w hose fetus became severely anemic despite intensive antepartum surveillance , the prevalence and characteristics of fetal Kell isoimmunization were rev iewed and analyzed. Cases with Kell and RhD alloimmunization requiring intr auterine intravascular transfusions (IUT) at the Mount Sinai Medical Center during the 13-year period ending March 1998 were compared. Thirty-six fetu ses with RhD and 5 with Kell isoimmunization required IUTs. Lower fetal and neonatal hematocrit levels were observed in the RhD group. A significantly higher incidence of polyhydramnios was found among fetuses with Kell isoim munization and the maternal serum titers were much lower than those in the RhD group, Delta OD450 values did not reliably reflect the Kell sensitized fetus's condition. There were no intrauterine deaths or neonatal direct hyp erbilirubinemia in the Kell group, and the hemolytic disease of the newborn was more severe in the RhD group. Although the course of the hemolytic dis ease in our cases of Kell isoimmunization showed a better prognosis than th at in the RhD group, the importance of this condition should not be underes timated, and differences in the pathophysiology of Kell and RhD alloimmuniz ation should be taken into consideration during the management of these cas es.