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104 Part III: Epochal Hematology Chapter 7: Hematology of the Fetus and Newborn 105

TABLE 7–3. The White Cell Count and the Differential Count during the First 2 Weeks after Birth*
Neutrophils
Age Leukocytes Total Segmented Bands Eosinophils Basophils Lymphocytes Monocytes
BIRTH
Mean 18.0 11.0 9.4 1.6 0.40 0.10 5.5 1.05
Range 9.0–30.0 6.0–26.0 — — 0.02–0.85 0–0.64 2.0–11.0 0.4–3.1
Mean % — 61 52 9 2.2 0.6 31 5.8
7 DAYS
Mean 12.2 5.5 4.7 0.83 0.50 0.05 5.0 1.1
Range 5.0–21.0 1.5–10.0 — — 0.07–1.1 0–0.25 2.0–17.0 0.3–2.7
Mean % — 45 39 6 4.1 0.4 41 9.1
14 DAYS
Mean 11.4 4.5 3.9 0.63 0.35 0.05 5.5 1.0
Range 5.0–20.0 1.0–9.5 — — 0.07–1.0 0–0.23 2.0–17.0 0.2–2.4
Mean % — 40 34 5.5 3.1 0.4 48 8.8
*All white cell counts are expressed as cells × 10 /L.
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Data from Altman PL, Dittmer DS: Blood and Other Body Fluids. Federation of American Societies for Experimental Biology, Washington, DC, 1961
and Dallman PR: Pediatrics, 16th edition. New York, NY: Appleton-Century-Crofts, 1977.

sensitive to osmotic hemolysis and to oxidant injury than are adult cells. diminished capacity of neonatal granulopoiesis, may impair the neo-
Newborn red cell membranes have higher total lipid, phospholipid, and natal response to infection. Smaller numbers of CFU-GM colonies
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cholesterol per cell than adult red cells. 128,129 The patterns of phospho- were observed in the blood of sick infants, who also have diminished
lipid and phospholipid fatty acid composition also differ from those in endogenous production of colony-stimulating factors in culture. The
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adult red cells. Red cells of newborns have the same pattern of mem- clinical use of cytokines to treat neonatal sepsis remains controversial,
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brane proteins on polyacrylamide gel electrophoresis and the same but circulating neutrophils are increased in preterm infants treated with
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rate of mobility in an electric field as do red cells from adults. After recombinant G-CSF, and the infants’ length of stay in the neonatal
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trypsin treatment of newborn and adult cells, however, there is a dif- intensive care unit is shortened. 143
ference in electrophoretic mobility, indicating that the surface trypsin- White Cell and Differential Counts Table 7–3 gives the values
resistant proteins are different. The relationship of the metabolic and for the white cell and differential counts during the first 2 weeks after
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membrane alterations in neonatal red cells to their shorter life span is birth. The absolute number of segmented neutrophils rises in both term
not clear. and premature infants in the first 24 hours. In term infants, the mean
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value increases from 8 × 10 /L to a peak of 13 × 10 /L and then falls to
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4 × 10 /L by 72 hours of age, remaining at this level through the follow-
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ing 7 days. In the premature infant, the mean values for neutrophils are
WHITE CELLS 5 × 10 /L at birth, 8 × 10 /L at 12 hours, and 4 × 10 /L at 72 hours. The
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Granulocytopoiesis and Monocytopoiesis mean count then falls gradually to 2.5 × 10 /L by the 28th postnatal day.
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Colony-Stimulating Factors and Granulomonopoiesis The absolute The level after the first 72 hours is very stable for an individual infant,
number of neutrophils in the blood of term and premature infants usu- whether term or premature. Immature forms, including an occasional
ally is greater than that found in older children (Table 7–3). The neu- promyelocyte and blast cell, may be seen in the blood of healthy infants
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trophil count tends to be lower in the premature than in the term infant, in the first few days after birth and are more frequent in premature
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and the proportion of myelocytes and band neutrophils is higher. infants than in term infants. Segmented granulocytes are the predom-
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Serum and urinary colony-stimulating activity are elevated during the inant cells in the first few days after birth. As their number decreases,
period of neutrophilia. When granulopoiesis was studied in cord the lymphocyte becomes the most numerous cell and remains so during
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blood, blood, and marrow of infants, the macrophage colony-forming the first 4 years of life. An absolute eosinophil count of greater than
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unit was predominant despite the clinical neutrophilia, and this pattern 0.7 × 10 /L was found in 76 percent of premature infants at 2 to 3
was not altered by different sources of colony-stimulating factors. 135,136 weeks of age. The onset of the eosinophilia coincided with the estab-
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The endogenous cytokines produced by mononuclear cells from cord lishment of steady weight gain in the infants. It is increased by the
or systemic venous blood support the growth of neutrophil colonies use of total parenteral nutrition, endotracheal intubation, and blood
in assays using marrow from adults. However, there is diminished transfusions.
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GM-CSF, G-CSF, and IL-3 production in stimulated newborn com-
pared to adult mononuclear cells, 137–139 which may limit the response to Phagocyte Functions
bacterial infection in the newborn. Furthermore, preterm infants have Bacterial infections are a major cause of morbidity and mortality in the
a reduced neutrophil storage pool and a restricted capacity to increase newborn period. The infections frequently are caused by organisms
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their progenitor proliferation, and their neutrophil count may fall pre- of low virulence in normal children and adults, including Staphylo-
cipitously with neonatal bacterial infection. Dysregulation, as well as coccus and Lancefield group B β-hemolytic streptococci, but, also, by
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