Authors of an analysis published recently in the Eastern Journal of Medicine determined transfusion blood products for minor blood groups should be made available to reduce morbidity and mortality associated with hemolytic disease of the fetus and newborn (HDFN).
HDFN is frequently caused by Rhesus (RhRh factor A protein or antigen found on red blood cells. When an Rh-negative mother carries an Rh-positive fetus, her immune system may make antibodies that attack the fetus' red blood cells.)D and ABO incompatibility, but it can also can be associated with minor blood groupBlood group A classification of blood based on inherited markers found on red blood cells. The ABO and Rh blood groups are most common in HDFN. systems, including Kell, Kidd, Duffy, P, MNS or the Rh subgroup (C, c, E, e) alloantibodies. The study authors retrospectively evaluated 11 cases of HDFN that were linked to Kell incompatibility, which is considered a rare cause of HDFN.
Understanding HDFN caused by Kell incompatability
Following the ABO and Rh blood group systems, Kell is considered a highly immunogenic blood group system. Anti-Ks, including anti-K1, anti-K2, anti-K3 and anti-K7, can frequently be the cause of HDFN and of transfusion reactions among newborns. In fact, these anti-Ks are considered to be the IgG antibodiesAntibody A protein made by the immune system that recognizes and attacks foreign substances, such as bacteria, or in HDFN, fetal red blood cells carrying incompatible antigens. that are responsible for targeting Kell antigensAntibody A protein made by the immune system that recognizes and attacks foreign substances, such as bacteria, or in HDFN, fetal red blood cells carrying incompatible antigens..
Read more about HDFN testing and diagnosis
The K antigen is one of the Kell blood group antigens that is generated early on in fetal development. In fact, because the K antigen is expressed in erythroid progenitor cells, which originate in the bone marrow and produce RBCs, antibodies to K may be associated with both hemolysis of mature erythrocytes and the blocking of normal erythrocytes.
HDFN related to anti-K can lead to serious complications. In those situations in which severe hyperbilirubinemiaHyperbilirubinemia A common cause of jaundice, this refers to higher than normal bilirubin levels in the blood. occurs, a disorder called bilirubinBilirubin A yellow substance produced when red blood cells break down. High bilirubin levels in newborns with HDFN can cause jaundice or, in severe cases, brain damage.-induced neurologic dysfunction (BIND) may be reported. There are many long-term adverse events associated with BIND, including hearing loss, intellectual disability and cerebral palsy.
Study methods and outcomes
The researchers examined the files of patients with a diagnosis of jaundiceJaundice A common symptom of HDFN, jaundice is caused by excess bilirubin and is characterized by a yellow tint to the skin or eyes. between January 2014 and September 2023. All of the patients had been diagnosed in a third-level neonatology unit of a university hospital located in Turkey. Ultimately, a total of eleven individuals with Kell incompatibility were included in the study—six boys and five girls.
Among the eleven patients with Kell incompatibility, two were born prematurely. Of note, none of the patients experienced elevated levels of direct bilirubin. All of the participants received phototherapyPhototherapy A treatment that uses special blue light to help newborns break down bilirubin and prevent kernicterus. as their initial treatment. One of the patients needed to undergo blood exchange because of elevated bilirubin concentrations in spite of the use of phototherapy. The use of intravenous immune globulin was not required in any of the patients.
In four of the cases, both Kell incompatibility and RhD subgroup incompatibility were reported. There were no treatment-related complications observed. No adverse events were linked to elevated total bilirubin levels.
“In cases of Kell incompatibility, the clinic may vary from mild jaundice to hydrops fetalisHydrops fetalis A serious, sometimes fatal condition in which fluid builds up in a baby’s tissues and organs due to severe anemia from HDFN.,” the authors noted. Almost all of the cases evaluated in the current analysis exhibited mild to moderate HDFN. “However, it should be kept in mind that serious hemolysis and related deaths may occur due to Kell incompatibility,” they emphasized.
“In order to reduce and prevent severe hemolysis due to Kell and other minor blood groups in newborns, transfusing blood products suitable for minor blood group to women of childbearing age (especially pregnant women) may be a correct approach as a country policy,” they concluded.
