B13 - Acute Leukaemia Flashcards
Acute Leukaemia
- Malignant leucocyte precursors in bone marrow (blast cells)
○ Abnormality occurs in cells only just committed to either lymphoid or myeloid - will proliferate and stall at this stage of development- Replacement of BM by leukaemic cells (blast cells) outgrow the normal bone marrow resulting in bone marrow failure
- Reduction in normal cells
- Leukaemia (blast) cells proliferate but do not mature
- Two main types:
○ lymphoid (lymphoblastic, ALL)
○ Myeloid (myeloblastic, AML) - Treatment chemotherapy +/- stem cell transplant
- Genetic change resulting in a clonal abnormality of a primitive cell leading to leukaemia
○ Originates in the bone marrow and goes to blood
two main types of acute leukaemia
○ lymphoid (lymphoblastic, ALL)
○ Myeloid (myeloblastic, AML)
Haemopoiesis
- Acute leukaemia
○ Differentiation from pluripotent cell to myeloid and lymphoid
○ Acute leukaemia occurs early in cells only just committed to myeloid or lymphoid - stall at this stage and do not differentiate further
haemopoeisis - chronic leukaemia
○ Still differentiate leading to mature end stage cells that resemble normal cells but do not function
○ The abnormality is probably still in the very early stem cell but it’s able to differentiate
acute leukaemia - clinical features
○ Affects all ages (children: predominantly ALL), increasing incidence with aging
○ Symptoms: bone marrow failure because the leukaemic cells replace normal haemopoiesis in the bone marrow - unable to make red blood cells and become anaemic
§ Anaemia
§ Leukopenia - not able to make white blood cells - leukopoiesis, granulopoiesis
§ Thrombocytopenia - not enough megakaryocytes so they cant make platelets leading to thrombocytopaenia, bleeding, bruising
§ Lethargy
§ Infections
§ Fevers
§ Bleeding
§ bruising
○ Acute monocytic leukaemia (subtype of acute myeloid leukaemia)
§ Cells would have been monocytes if they had matured properly
§ Gum hypertrophy, gingival enlargement (enlarged gums with bleeding or swelling due to leukaemic infiltration of that tissue)
§ Red swollen gingiva (gums around teeth) due to leukaemia cells
○ Bone marrow replaced by immature blast cells (leukaemic cells)
§ Immature, fine chromatin (purple inside the nucleus is lighter in colour), nucleolus (pale staining region within the nucleus)
§ Variable amounts of cytoplasm - sometimes there are granules or other things giving an indication as to the type of cell
§ Don’t look like normal end stage cells
○ Blood count reduced with circulating blast cells
§ Type of leukemia determined by
□ Cell appearance (morphology)
□ Biomarkers (flow cytometry) or cellular antigens
□ Cell chromosomes of the leukaemic - to see if they differ from normal, or have chromosomes that are associated with a specific type of leukaemia and the likely prognosis
○ Cellular antigens expressed determines cell lineage - lymphoid or myeloid, B cell or T cell (if lymphoid)
§ B lineage: CD10, CD19, CD79a
§ T lineage: CD2, CD3, CD7
§ Myeloid: CD13, CD33, CD64, CD117
markers of B cell lineage
§ B lineage: CD10, CD19, CD79a
markers of T cell lineage
§ T lineage: CD2, CD3, CD7
markers of myeloid lineage
§ Myeloid: CD13, CD33, CD64, CD117
Stage of differentiation (maturity):
CD34, TdT - both markers that indicate immaturity, early in differentiation
Therapy
○ Depending on age and whether we are treating with curative intent
○ Aggressive cytotoxic chemotherapy (curative intent - kill or immortalise leukaemic cells in bone marrow, also kills normal haemopoietic cells causing prolonged pancytopenia - normal cells will have a low count (for two or three weeks) until bone marrow can recover
§ Generally needs more than 1 course because it can recur
§ Require multiple cycles
○ Bone marrow transplantation (allo from someone else - as opposed to auto)
§ Allogeneic - from another person
○ Monoclonal antibody therapy - more personalised and targeted
○ Specific targeted inhibitors
○ S/E prolonged pancytopenia
§ Blood transfusions, antibiotics - managing side effects
○ Antibiotics
○ Cytokines (e.g. G-CSF)
§ to encourage bone marrow to make more normal blood
§ be careful you are not encouraging growth of more leukaemia
Precursor Lymphoid Leukaemia
- Also called: acute lymphoblastic leukaemia
- Neoplastic (cancerous) proliferation of precursor cell committed to B or T lymphoid lineage (lymphoblastic leukaemia) 85% will be B cell lineage
- Somatic mutation in early progenitor cell
- Presentation
○ Symptoms of BM failure: anaemia, infection, bleeding
○ Organ infiltration: lymph nodes, spleen, liver, thymus
§ Organs that normally contain lots of lymphoid cells
§ Thymus only if it is T cell - Age: child or adult
- Diagnosis: morphological blood and bone marrow examination
- Classification: phenotype, genetics (chromosomes)
- Prognosis: child=good (high cure rate 85-90%), adult=poor (we don’t fully know why adults have worse prognosis)
- Most common leukaemia in children - if the child is 2-5 they have a good prognosis - 90% cure rate
- 3.4/100 000
Precursor Lymphoid Leukaemia prognosis
- Prognosis: child=good (high cure rate 85-90%), adult=poor (we don’t fully know why adults have worse prognosis)
- Most common leukaemia in children - if the child is 2-5 they have a good prognosis - 90% cure rate
Precursor Lymphoid Leukaemia presentation
○ Symptoms of BM failure: anaemia, infection, bleeding
○ Organ infiltration: lymph nodes, spleen, liver, thymus
§ Organs that normally contain lots of lymphoid cells
§ Thymus only if it is T cell
Precursor Lymphoid Leukaemia - Children
○ ALL most common in children
○ B-lineage ALL
§ Accounts for 85% of ALL in children
○ T-lineage ALL
§ 15% of ALL in children
○ Childhood ALL: 90% cure (30-40% in adults)
precursor lymphoid leukaemia symptoms
○ Anaemia, lethargy, leukopenia, thrombocytopenia, blast cells, infections, fevers, bleeding, bruising, bone pain, weight loss, loss of appetite
- B-lineage ALL
○ Commonest leukaemia in children
○ Small blast cell
○ Precursor B cell
§ Antigens: CD10 (immature B cell), CD19 (B cell associated antigen), TdT positive (marker of immaturity)