3.19 STROM Overview of Hematopoiesis Flashcards
Epo
Endogenous/exogenous causes an increase in RBC, 90% produced by kidney (renal failure leads to anemia) and can give as drug to increase RBC
TPO
Leads to increase in platelet formation
G-CSF
Increase Neutrophils, decrease apoptosis, cause functional activation and decrease Monocytes
GM-CSF
Multipotential growth factor with overlapping activity (upstream of G-CSF) still has action on increasing Neutrophils
Maturation of Granulocyte
“BLAST” to
1st ID-able cell for path way: (1)promyelocyte
(2) Myelocyte
(3) Metamyelocyte
(4) Bands and (5) Neutrophils
-amplification at every step of all have more neutrophils than any other cell type-true with all of these pathways
-G-CSF is key regulator/stimulator of granulopoiesis/myelopoiesis
Thrombopoiesis
“BLAST” to
(1) Immature Megakaryocytes
(2) Mature Megakaryocytes
- POLYPLOID: avg 16-32 haploid genomes at a time
- Make platelets
- PROPLATELETS get lopped off to form mature platelets
Thrombopoietin Regulation of Thrombopoiesis
-Constantly made by liver
-bind both megakaryocytes (platelet production) and platelets (bind up and prevent mega binding)
-If platelet # is low TPO will be less bound an able to bind megakaryocytes leading to platelet production
(Endogenous Action)
Maturation of granulocyte
“BLAST” to
(1) Pronormoblast
(2) Basophilic Erythroblast
(3) Polychromatophilic Erythroblast (accumulation of Hgb)
(4) Normochromic Erythroblast exit of nuclei turns into (5) Polychromasic reticulocyte and then matures to (6) RBC
RBC induced Anemia b/c of Iron Deficiency
Morphology: (1) MICROCYTOSIS (small) and HYPOCHROMIA (Pale, lack Hgb)
(2) ANISOCYTOSIS (variable size) and POIKILOCYTOSIS (variable shape)
Fe Absorption
GI Tract: Fe+++ (ferric) to Fe++ (ferrous) via Ascorbate
PLASMA: Fe++ to Fe+++ via serum oxidases
-loaded onto serum transferrin
SERUM IRON TEST
-look at how much Fe is bound to transferrin in the plasma
Total Iron Binding Capacity (TIBC)
Tells if Serum Iron is low due to reduced transferrin or not
- High binding capacity means there is plenty of transferrin waiting to bind Fe (means there is an Iron Deficiency)
- [Serum Fe]/TIBC =% of Transferrin Saturation
- Iron Def should also cause increase in serum transferrin production
Soluble Transferrin Receptor Level
-Macrophages increase production in low iron state to try and get iron make so many they are measurable
Measure Ferritin
Storage form of Iron
- Strom’s FAVORITE!!!
- Decreased ferritin in rarely caused by anything else other than Iron deficiency
- look for “trace” levels/barely detectable
- Macros taking up ferritin to make RBC but do not have enough IRON
- Will be depleted before anemia starts
Thalassemia
-Globulin syn pathway
Heterogenous group of GENETIC disorders that result from decreased rate of synthesis of alpha or beta chain on Hgb
-Some can cause anemia
Beta Chain Defects
Morphology: (1) microcytosis & hypochromia (like Fe Def but cells are smaller usually)
(2) Frequent target cells (nonspecific)
(3) can be severe if homo; mild or clinically insig if hetero (GOD’s WAY)
-Have two functional copies in normal
LAB VALUES:
(1) Microcytic anemia with (2) Normal or Increased RBC
-Use Hgb Electrophoresis Test to confirm
–look for increased Hgb A2: (alpha2,delta2) and will also see some fetal Hgb: (alpha2,delta2)
NORMAL: alpha2,beta2
Alpha chain Defects
Normal has 4 functional alpha genes
-alpha thalassemia 1 trait: clinically irrelevant, only a single mutation on one gene (of 4)
ALPHA THAL 2 TRAIT
mild microcytic anemia, see gamma4 chain (Bart’s)at birth and normall chains later in life
–2 defective alleles, diagnose with PCR under diagnosed
Hgb H disease (beta4)
3 mutant alpha genes
- have excess beta chain they form tetramer that is a func Hgb
- commonly misdiagnosed as IRON DEF, variable degree of microcytic anemia
- Hgb electrophoresis to diagnose
Hgb Bart’s (gamma4)
Four defective copies
- usaully lethal in utero
- if baby lives makes Bart’s Hgb, will no survive long enough to beta chain (takes time to develop)
