13) Granulocytes & monocytes Flashcards
normal diff ranges for an adult
- 40-80% segs
- 0-5% bands
- 25-35% lymphs
- 2-10% monos
- 0-5% eos
- 0-1% basos
general changes that occur as grans mature
Nucleus
- chromatin condenses
- nucleoli lost
- indentation
Cytoplasm
- loses RNA (less blue)
- no granules → primary granules → secondary granules
6 morphologically identifiable gran stages
- myeloblast
- promyelocte
- myelocyte
- metamyelocyte
- band neutrophil
- segmented neutrophil
- high N:C ratio
- nucleus round or oval, smooth
- 1-5 nucleoli visible
- small blue cytoplasm
- no granules
- larger than a lymph
blast
auer rods
pink/red splinters made of fused primary granules
found in myeloblasts, monoblasts, pros
- high N:C ratio
- smooth chromatin, slightly coarse
- several nucleoli
- nucleus frequently eccentric
- blue cytoplasm with prominent primary granules
- granules often overlay nucleus
pro
last gran stage capable of mitosis
goes through 2-3 divisions
myelocyte
first gran stage committed to one of the 3 lines
myelocyte
- nucleus round, oval or flattened on one side
- chromatin beginning to clump
- nucleoli usually not visible
- pale area visible next to nucleus
- secondary granules appear, cytoplasm less blue
myelo
dawn of neutrophilia
secondary granules made by the Golgi, which appears as a pale area next to the nucleus of a myelo
peroxidase = granules
secondary
peroxidase + granules
primary
vesicles formed by endocytosis
fuse with plasma membrane upon activation, allowing expression of adhesion and chemotactic receptors
secretory vesicles
secretory vesicle first appear in…
myelos
- coarse and clumping chromatin
- no nucleoli visible
- nuclear indentation <1/2 diameter
- pinkish tan cytoplasm
- predominance of secondary granules
meta
- clumped chromatin
- indentation >1/2 diameter
- no filaments
- pinkish tan cytoplasm
band
hyposegmented neutro
1-2 lobes in most
hypersegmented neutro
5 or more lobes in 5 or more cells
barr body
inactive X chromosome
extension of nucleus on a seg
only in women
clinically insignificant
3 compartments where neutros spend their life
BM
PB
tissues
2 pools of BM neutros and characteristics
- mitotic pool/proliferating pool—3-6 days—capable of DNA synth—blasts, pros, myelos
- postmitotic pool—5-7 days—metas, bands, segs—3x size of mitotic pool
2 pools of PB neutros
- circulating pool—drawn in CBC
- marginal pool—rolling along vessel walls
freely exchange
50:50 ratio
neutros spend —– hours in PB before diapedesing
7.5
blast:pro:myelo:meta:band:seg ratio in BM
1:3:12:16:12:7
neutros usually live for ——– days in tissue, but GM-CSF and C-CSF can increase this to ——- days
1-2
3-5
neutros time spent in BM
1-2 weeks
stem cell → blast
stem cell
CMP
CFU-GEMM
CFU-GM
CFU-G
blast
4 steps of neutro function
- adherence
- migration/chemotaxis
- phagocytosis
- bacterial killing
interaction between neutro and vascular endothelial cells (VECs)
adhesion
VEC
vascular endothelial cells
types of cell adhesion molecules that facilitate adherence
- selectins
- integrins
- ICAMs
on activated VECs and inactivated neutros
bind loosely
selectins
selectins on VEC and neutro
VEC: E-selectin, P-selectin
neutro: L-selectin
———- is always present on the neutro in absence of cytokines, but cytokines cause upregulation
L-selectin
β2 family are ———-
integrins
on activated neutros
bind tightly to VECs
integrins
on activated VEC
bind tightly to neutros
ICAMs
ICAM
intercellular adhesion molecules
bind tightly, causing arrest of neutro
β2 integrin on neutro and ICAM on VEC
stages of neutrophil adherence and diapedesis
- Loose attachment—selectins on VEC activated; transiently associated with L-selectin; allow rolling adhesion
- Activation of neutros—chemokines & chemoattractants activate neutrophil to express integrins; L-selectin downregulated
- Arrest of neutrophil—neutro β2 integrin + VEC ICAM allows tight binding; cytoskeleton of neutro changes shape and NADPH oxidase membrane complexes are assembled to prepare for bacterial killing
- Diapedesis—neutrophils follow chemoattractants into tissue; neutro enzymes like gelatinase B help dissolve basement membranes
neutrophils move toward targets with ——– motion
ameboid
stages of neutro phagocytosis
- recognition and binding
- engulfment
- formation of phagosome
- phagolysosome fusion
- killing and digestion
- exocytosis
2 ligands that neutros use to phagocytize
PAMPs (pathogen associated molecular patterns)
Opsonins (IgG, C3)
2 types of neutro microbicidal mechanisms
- oxygen-dependent/oxidative
- oxygen-indepentent
oxidative microbicidal mechanisms in neutro
- respiratory burst
- myeloperoxidase (MPO)
respiratory burst
NADPH oxidase generates and pours reactive oxygen species into phagosome
MPO action
catalyzes interaction of H2O2 produced during resp burst with halides
oxidized halogens increase bacterial killing
examples of oxygen-independent mechanisms in neutro
- acid pH
- lysozyme
- lactoferrin
- defensins
- collagenase
- hydrolases
a normal left shift does not include ——– or ———
pros or blasts
causes of neutrophilia
- bacterial infection
- metabolic intoxication
- drug intoxication
- tissue necrosis
- shift from marginating pool to circulating pool (no net increase)
- reduced egress of neutros from blood to tissues
normal neutrophilia during infection
10-25
changes to neutros during infection
- left shift
- toxic gran
- dohle bodies
- vacuolization
pseudoneutrophilia/shift neutrophilia
result of redistribution from marginating to circulating pool
causes of pseudoneutrophilia
- active exercise
- epinephrine
- anesthesia
- stress
leukemoid reaction
extreme benign neutrophilia
due to severe infection or necrotizing tissue
how to tell CML apart from leukemoid reaction
In leukemoid rxn…
- WBC count <50 usually
- inclusions: toxic gran, dohle bodies, vacuoles
- usually no blasts
- transient
- normal karyotype (no Philadelphia chromosome)
- ↑ LAP in 90-95% pts
- rare to have ↑ basos or eos
- no blue histiocytes, pseudo-gaucher, or pseudo-PH
- normal platelet morphology, may be ↑
ANC defining neutropenia
<1.8
major cytokines affecting eosinophil differentiation
- IL-5 released by TH2 cells
- GM-CSF
- IL-3
3 types of eo granules
- primary granules
- small granules
- specific/secondary granules
eo’s specific granules contents
- major basic protein
- eosinophil cationic protein
- eosinophil peroxidase
- eosinophil derived neurotoxin
eos are influenced by the ———- part of the immune system
cellular/T cell
host defense against helminths
eos
eosinophilia
> 0.45
when is eosinophilia seen?
- allergic diseases
- parasitic infections
- toxic reactions
- GI diseases
- resp tract disorders
- certain neoplastic disorders
how long do eos spend in PB before migrating to tissues?
18 hours
basophilic granules contain…
- histamine
- heparin
- cathepsin G
- major basic protein
- lysophospholipase
how are basos different from masts?
Basos
- found in PB, not tissues
- mature in BM
- do not proliferate
- live for days
- segmented nucleus
- varying amt of granules
Masts
- found in BM and tissues, not PB
- mature in tissues
- proliferative potential
- live weeks to months
- round nucleus
- cytoplasm completely full of dense granules
mediators of inflammatory response
asthma, urticaria, allergic rhinitis, anaphylaxis
basos
have receptors for IgE
basos
baso enzymes cause…
vasodilation
bronchoconstriction
chemotaxis
basos express ——— ligand to induce IgE class switching in B cells
CD40
monocyte precursors
- monoblasts
- promonocyte
- ovoid or round nucleus, folded or indented
- pale purple fine chromatin
- several nucleoli
- abundant agranular blue-gray cytoplasm
monoblast
nonspecific esterase activity, inhibited by Na fluoride
monoblast
- irregular, indented nucleus with fine chromatin
- may have nucleoli
- abundant blue-gray cytoplasm
- fine azurophilic granules
promonocyte
2 types of monocyte granules
- contains peroxidase, acid phosphatase, arylsulfatase
- not much known about the other
histiocytes
tissue macrophages
no significant storage pool in BM
monos
monos time in BM
54 hours
monos spend —— hours in PB before they diapedese
8
