Chapter 13 Robbins Flashcards
What can stimulate HSCs in marrow to move from stem cell niches?
G-CSF
Response to stress
Marrow response to short term needs
Controlled by growth factors that act on committed progenitors
Growth factors acting on EARLY committed progenitors
KIT ligand and FLT3-ligand
Growth factors acting on restricted progenitors
Erythropoietin, GM-CSF, G-CSF, and thrombopoietin
Distortion of marrow architecture can lead to
Abnormal release of immature precursors (leukoerythroblastosis)
Fat cells increase in bone marrow in
Hypoplastic states
And decrease in neoplastic or hyperplastic states
Leukopenia usually results from
Decreased number of neutrophils
Usually associated with decreased function of granulocytes
Lymphopenia most commonly from
HIV, glucocorticoid therapy, autoimmune disorders, malnutrition and viral infections
Usually a redistribution (to LN and tissue) rather than a decrease in number
Cause of neutropenia
Inadequate/ineffective granulopoiesis
Increased destruction/sequestions
Suppression of HSCs causing neutropenia
Aplastic anemia, tumors, granulomatous disease
Accompanied by anemia and thrombocytopenia
Suppression of granulocyte committed precursors causing neutropenia
Drug toxicity
Ineffective hematopoiesis causing neutropenia
Megaloblastic anemias, myelodysplastic syndromes (precursors die in the marrow)
Congenital syndromes causing neutropenia
Kostmann syndrome
Impairs differentiation of granulocytes
Immune mediated destruction of neutrophils
Can be idiopathic, associated with a disease like SLE, or drug toxicity related
Effect of splenomegaly on neutrophils
Increased sequestration
Sometimes associated with anemia and thrombocytopenia
Increased peripheral utilization of neutrophils occurs with
Bacterial, fungal and rickettsial infections
Most common cause of agranulocytosis
Drug toxicity
Red cells and platelets also effected
Aminopyrine, chloramphenicol, sulfonamides, chlorpromazine, thiouracil, and phenylbutazone
Chlorpromazine effect on neutrophils
Direct toxicity
Sulfonamide effect on neutrophils
Antibody mediated destruction
LGL leukemia effect on neutrophils
Monoclonal proliferation of lymphocytes suppresses production of neutrophils
Morphological consequences of neutropenia
Compensatory marrow hyperplasia Increased infections (candida and aspergillus)
Clinical features of neutropenia
Related to infection - serious infections when under count of 500
Fever, malaise, and chills
Peripheral leukocyte count
Size of precursor and storage pools
Rate of release into circulation
Size of marginal pool (adhering to BV)
Rate moving into tissues