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998 Part VII: Neutrophils, Eosinophils, Basophils, and Mast Cells Chapter 65: Neutropenia and Neutrophilia 999

Marrow pools Blood pools Mechanism Causes
Mitotic Maturation Storage Marginal &
circulating

MP
M.P. MaP SP Normal
CP
Acute disorders—
stress,
Marrow storage intoxications,
pool shift hypoxia,
infections, etc.
Endotoxins
Corticosteroids
Etiocholanolone
Acute disorders—
Marginal stress,
pool shift
intoxications,
hypoxia,
infections, etc.
Exercise
Egress from Adrenalin
circulating pool Corticosteroids

Chronic disorders—
infections,
tumors,
Proliferation endocrinopathies,
inflammation, etc.
Postneutropenia
Myeloproliferative
disorders
Proliferation
+ Chronic myelogenous
leukemia
peripheral
granulocyte
survival
Figure 65–4. Mechanisms of neutrophilia are shown schematically. The rate of flow of cells through each compartment is represented by the size
of the arrows. CP, circulating neutrophil pool; MaP, maturation (postmitotic) pool; M.P., mitotic pool; MP, marginated neutrophil pool; SP, storage pool
(marrow reserves).

neutrophils is the most frequent cause of an increased total white cell reduced egress of neutrophils from the blood to tissues, or a combi-
count. Granulocytosis is less specific than neutrophilia, because granulo- nation of these mechanisms. The time required for these events varies
cytes include eosinophils and basophils as well as neutrophils. Extreme substantially. Shifts between the marginal and circulating pools take
neutrophilia often is referred to as a leukemoid reaction because the only a few minutes. Shifts of neutrophils from the marrow to the blood
height of the white cell count may suggest leukemia. This exaggerated occur within a few hours. Increases in the production of neutrophils,
reaction may be the result of segmented neutrophils or may be associ- even with intense stimulation, may take at least a few days (Fig. 65–4).
ated with band neutrophils, metamyelocytes, and myelocytes in smaller With sustained moderate to marked neutrophilia the cause is virtually
proportions. always increased production of neutrophils.
In normal individuals, the neutrophil count follows a diurnal pat-
tern of variation, with peak counts in the late afternoon. Neutrophil Acute Neutrophilia
counts also rise slightly after meals, with erect posture, and with emo- Pseudoneutrophilia (Demargination) Vigorous exercise and acute
tional stimuli. Ordinarily these changes are not sufficient to cause physical and emotional stress can increase the number of blood neu-
neutrophilia. 134
136
trophils within a few minutes. The response is mimicked by infu-
sion of epinephrine and other catecholamines that increase heart rate
and cardiac output. The response is caused by a shift of cells from
137
MECHANISMS OF NEUTROPHILIA the marginal to the circulating pool; hence, it frequently is referred to
Under normal circumstances, neutrophils follow an orderly progres- as demargination. This response in humans is dependent partially on
sion from the marrow through the blood to tissue sites of utilization. release of neutrophils from the spleen, but redistribution from other
138
135
Mild neutrophilia may occur by several mechanisms: increased cell pro- vascular beds, particularly the pulmonary capillaries, is quantitatively
duction, accelerated release of cells from the marrow into the blood, more important. This mechanism can account for about a doubling in
shift within the circulation from the marginal to the circulating pool, neutrophil count. Greater elevations in neutrophils cannot be ascribed

Kaushansky_chapter 65_p0991-1004.indd 999 9/17/15 6:44 PM