Neutropenia: A reduced level of neutrophils, a specialized kind of white blood cell.
Normal Lab Values: 6-26 x 10 9/L for newborns. Decreases to 1-9 x 10 9/L at 1 month of age.
Neutropenia as a result of maternal alloimmunization has been documented since 1960 and still occurs in 45% of infants with HDFN 1 today. The child’s body is so busy producing red blood cells to compensate for the ones destroyed by the antibodies, that it simply does not produce other blood cells including white blood cells (neutrophils), and platelets (thrombocytes) 2. This can lead to neutropenia – a low level of neutrophils. In addition to neutropenia, leukopenia has also been known to occur 3. While all hydropic infants in Koenig’s paper 2 were neutropenic, hydrops is not a requirement for neutropenia – even mildly affected infants with HDFN can be neutropenic.
Neutropenia due to HDFN can persist for a year in some cases. Many neutropenic infants do not require treatment for neutropenia and are simply monitored via blood draws. In some cases neutropenia is treated with recombinant human granulocyte colony-stimulating factor may be administered to boost the neutrophil count 4.
Infants with neturopenia are at a higher risk for infection and may become sick more easily. Parents should be made aware of the risks of neutropenia and encouraged to take extra precautions to reduce infection (reduced visitors, increased hand washing, covering the car seat/stroller when out in public). If a neutropenic infant does become sick, he or she should be taken to the doctor as soon as possible – it is common for neutropenic infants to need antibiotics and additional medications to get over an illness.
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