Pathology - WBCs Flashcards
Characteristic features of Haematopoetic Stem Cells include:
Pluripotency
Capacity for self-renewal
Besides congenital immunodeficiency diseases, lymphopenia is associated with which diseases/states?
HIV Viral infections Glucocorticoid or cytotoxic therapy Autoimmune disorders Malnutrition
What is the most common cause of agranulocytosis?
Drug toxicity.
Alkylating agents and anti metabolites are often at fault.
Monocytosis is associated with which conditions?
Chronic infections; TB, SBE, Malaria
Collagen vascular diseases; SLE
IBD
Eosinophilia is associated with which conditions?
Allergies, parasitic infections, drug reactions, lymphomas, vasculitides.
Follicular hyperplasia is characterised by what histological appearance?
Prominent large germinal centres (secondary follicles) surrounded by a rim of resting naive B cells (the mantle zone)
Where do B cells reside in lymph nodes?
B-cells aggregate in follicles in the outer cortex.
What are primary and secondary follicles?
What is a germinal centre?
In unstimulated lymph nodes, B-cells form primary follicles, composed of follicular dendritic cells.
After antigenic challenge they form secondary follicles and express IgG and IgM.
A germinal centre is the pale staining centre of a secondary follicles which contains proliferating B cells and follicular dentritic cells.
What is the importance of the germinal centre in a lymph node?
Germinal centres are greatly enlarged in secondary antibody responses and are regarded as important sites of B-cell maturation and generation of B-cell memory.
What causes follicular hyperplasia?
Inflammatory processes that activate B-cells:
RA
Toxoplasmosis
Early HIV infection
What is the mantle zone?
Simply a rim of resting, naive, B-cells
Acute viral infections cause what type of lymph node reaction?
Paracortical hyperplasia:
Large T cell partially efface B-cell follicles.
What are the 3 broad categories of white cell neoplasm?
Lymphoid: B, T, NK cells neoplasms
Myeloid: AMLs, Myelodysplasias, chronic myeloproliferative disorders.
Histiocytoses: Macrophage or dendritic neoplasms.
Which 3 viruses are associated with white cell malignancies?
Human T Cell Leukaemia Virus 1:
Associated with adult T cell leukaemia
Ebstein Barr Virus:
Subset of Burkitt’s. 30-40% of HL. B-cell lymphomas and NK lymphomas.
Human Herpes Virus-8:
Large B-cell lymphomas.
H. pylori is associated with what malignancy?
Coeliac’s is associated with what malignancy?
Gastric B-cell lymphoma.
Intestinal T-cell lymphoma.
How can we distinguish lymphoid reactivity versus malignancy?
Reactive lymphocytosis is polyclonal, lymphoid neoplasms are monoclonal.
ALL are neoplasms of what cell type?
Immature precursor B (85%) or precursor T lymphoblasts.
Pre-T ALL tends to occur in which population?
Adolescent boys as thymic lymphoma (50-70% of cases)
Are single gene mutations sufficient to cause ALL?
Explain.
No. Additional, complementary mutations, which typically increase survival or proliferation are necessary to convert a pre-leukaemic clone to full blown malignancy.
Peak incidence for B cell ALL?
Peak incidence for T cell ALL?
3 years
Adolescence
Both occur less frequently in adults.
Pathognomonic features of CLL/SLL?
Proliferation centres (clusters of mitotically active cells).
Smudge cells are often present but not pathognomonic.
Prognosis of ALL?
With aggressive chemo: 95% of children achieve remission, 75-85% are cured.
Age less than 2 or greater than 10 or t9:22 chromosome are poor prognostic features.
Prognosis of CLL?
Variable: median survival is 4-6 years. May be up to 10.
With transformation: 1 year.
What is Richter syndrome?
Transformation of CLL to diffuse Large B-cell Lymphoma. Occurs in 5-10% of CLL cf prolymphocytic transformation in 15-30%. Bad news.
