B14 - Chronic Leukaemia Flashcards
chronic leukaemia
Clonal defect may be early but cell still has capacity to generate end stage cells
‘acute’ means patients would die quickly without treatment, chronic means they can live with their disease - ‘acute’ is only in relation to having no treatment
Chronic cells look like end stage blood cells, very few of them are curable
Acute is better defined as an ealry progenitor
Chronic - cells can differentiate and look like end stage blood cells
types of chronic lymphoid leukaemia
- malignant proliferation of what looks like mature myeloid or mature lymphoid cells even though the defect may have occurred early in cell development
- Types
○ Chronic myeloid leukaemia
○ chronic lymphocytic leukaemia - Subtypes
○ Myeloproliferative neoplasms
○ Hairy cell leukaemia B
○ B-prolymphocytic leukaemia
○ T-prolymphocytic leukaemia
Chronic lymphocytic leukaemia (CLL)
- 7/100 000 (commonest blood cancer in the western world)
- Uncommon in Asian communities
- Disease of the elderly >60 years (3% population)
- Some blood donors have sub clinical chronic lymphocytic leukaemia, can be detected but the patient has no symptoms
- 1400 new cases per annum in Australia
- Slight male predominance
- Neoplastic proliferation of mature B lymphocytic cells
CLL presentation
- Presentation
○ Lymphadenopathy (enlarged lymph nodes, because lymphocytes are made in bone marrow and will circulate in the blood - lymph nodes are primary lymphoid tissue)
○ Lymph node involvement
○ Recurrent infections due to supressed immune system, low immunoglobulin and reduced cellular immunity
CLL typical age
- Age: adults, elderly
CLL B cell levels
- > 5x10^9 monoclonal B cells in PB
○ Diagnosed when total count of B cells with particular phenotyping of CLL characteristics exceed these values
○ Normal B-lymphocyte count is 1x10^9
○ Diagnosed when there is 5x upper end of the reference range
CLL morphology
○ Small, mature lymphocytosis with smear cells (broken in the process of making the blood film)
○ Minimal cytoplasm
○ Nucleus has condensed clumped darkly stained chromatin
CLL clinical features
○ Symptoms
§ Anaemia, neutropenia, thrombocytopenia, lymphocytosis, lethargy
§ Infections, fevers, bleeding, bruising, fevers, night sweats, weight loss (bone marrow compromise)
§ May be asymptomatic
○ Signs
§ Enlarged liver and spleen (hepatomegaly and splenomegaly)
§ Enlarged lymph nodes (lymphadenopathy)
§ May affect tonsils, salivary glands
CLL blood count
○ >5x10^9/L cells for at least 3 months
○ Majority of patients have had a blood count for some other reason and it happens to be detected
CLL morphology
○ Small, mature lymphocytosis with smear cells
○ Minimal cytoplasm: condensed chromatin
CLL - B-cell phenotype/antigenic profile:
○ CD19 (B cell marker)
○ CD23 (most B cells do not express, but CLL are generally CD23 positive)
○ CD79a (B cell marker)
○ CD5 (T-cell associated antigen that is expressed in malignant b cells in chronic lymphocytic leukaemia for some reason)
○ kappa or lambda light chain restriction (light chains of immunoglobulin molecule - because they are clonal, they will express one or the other - either all kappa or all lambda) - can be determined to be leukaemic if they all have the same one
CLL - Flow cytometry/immunophenotyping
○ B-lymphocytes: CD19, CD20w (b cell antigen), CD23, CD79a, CD200 (b cell associated marker), kappa or lambda light chain
○ Aberrant expression of CD5 (a t cell antigen)
§ CD5 and CD23 is leukaemic
CLL - Cytogenetic studies
○ Good prognosis: trisomy 12, del 13q
○ Poor prognosis: del(11q), del(17p)
○ FISH: spots of chromosome 12
- FISH for +12 in CLL
○ Using probes for chromosomal regions and looking at them within the nucleous of cells
○ Immuno-flowFISH: WA invention to detect chromosome abnormalities in immunophenotyped CLL cells using flow cytometry
○ ○ Left: trisomy 12 - three pink spots ○ Right: P53 (tumour suppressor gene) deletion in some cells on the short arm of chromosome 17 ○ Blue colour indicates the nucleus ○ Fluorescent In-Situ Hybridisation § Hybridise a probe bought from a manufacturer with the cells ○ Invention at UWA § Combining immunophenotyping of cells and fish test in one test § Analyse 100 000 cells instead of just 100 § Much more sensitive § Gives prognostic information - tells what treatment is needed
- CLL for del(17p)
○ TP53/del17p deletions or mutations and prognosis
○ A different disease
○ Short survival
○ Different treatment
○ FISH sensitivity: 5-7% del (17p)
§ 7% of the cells have to have the abnormality
○ Antigens: CD3, CD5 (marker of CLL), CD19, FISH: CEP17, 17p12
○ Need specialised therapy