A rare case of hemolytic disease of the fetus and newborn (HDFN) caused by anti-Fya antibodies highlights the importance of expanded antibody screening during pregnancy, according to a case report published recently in the International Journal of Pathology.
HDFN occurs when a mother’s immune system creates antibodies that attack the red blood cells of her fetus. Although most known cases result from Rh or ABO incompatibility, this case involved a less common cause, an alloantibody to the Duffy (Fya) antigen.
The case involved a preterm male infant born at 35 weeks gestation with a birth weight of 3.2 kg. At 12 days old, the child was admitted to the hospital with a five-day history of jaundice, and his weight had dropped to 2.6 kg. While the baby was deeply jaundiced, no active bleeding was observed. Bloodwork showed elevated bilirubin levels at 19 mg/dL and a positive direct antiglobulin test, suggesting antibody-mediated red blood cell destruction.
“The case report highlights the importance of minor blood group antibody screening for pregnant women,” the authors wrote. “Positive cases need thorough testing for antibody titers together with regular checks of fetal antenatal well-being.”
Read more about HDFN causes and risk factors
The infant’s mother, who had gestational diabetes and no history of Rhogam treatment, was blood type O negative and had previously been transfused. Her antibody screen showed high titers of anti-D, anti-C, and anti-Fya antibodies. The baby’s blood type was B negative, and initial compatibility testing confirmed that the baby’s red cells were incompatible with maternal antibodies, even though anti-Fya antibodies were not detected in the infant’s serum at that time.
Despite a lack of free anti-Fya antibodies in the baby’s blood, likely due to all available antigenic sites already being bound, a later test 1.5 months after birth showed that the baby was indeed Fya positive and no longer direct antiglobulin test positive, confirming previous sensitization. The child had received phototherapy, which helped manage the symptoms.
This case shows how minor blood group incompatibilities can cause serious health issues. Early screening for less common antibodies such as anti-Fya could allow doctors to plan treatments sooner and reduce complications. For pregnant patients, a single additional blood test could one day mean the difference between standard newborn care and emergency intervention.
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