JC42 (Medicine) - Leukaemia, Bone Marrow Transplant, Immunogenetics Flashcards
Leukocytosis
- 2 broad category of causes
- Normal Total WBC count in adult
- Typical adult reference range for differentials (/)
Leukocytosis: quantitative abnormality in WBC
Causes: can be classified into
→ Reactive as the result of complex interactions between cells, cytokines and peripheral, tissue and marrow WBC pool
→ Neoplastic as the result of acquired genetic changes leading to malignant transformation
Total WBC: 7.5 ± 3.5×109/L (4 – 11)
Neutrophil: 20 – 7.5
Lymphocytes: 1.5 – 4.0
Monocytes: 0.2 - 0.8
Eosinophil: 0.04 - 0.4
Basophil: 0.02 - 0.1
Outline questions to identify cause of lymphocytosis
- Fever and features of infection
- Bone pain: infection or leukemia
- S/S of inflammation, eg. rash, photosensitivity, joint pain
- S/S of malignancies, eg. hepatosplenomegaly, lymphadenopathy, palpable mass
- S/S of allergies, eg. rhinitis, asthma, rash, urticaria, angioedema, atopy esp for unexplained eosinophilia
- Symptoms of other lineages, eg. bleeding, anaemia
- TOCC esp travel for unexplained eosinophilia
- Past medical history
- Drug history
Describe the following PBS results + give D/dx
- Left shift
- Leucoerythroblastic picture
- High Blast count
- Auer rods, Faggot cells
- Atypical lymphocytosis
- Left shift: Immature granulocytes – Severe infection/ Sepsis or CML
- Leucoerythroblastic picture: Immature granulocytes + Nucleated RBC +/- Tear drop RBC – Marrow infiltration by Primary MF or metastatic CA
- High Blast count – >20% blast qualifies as acute leukaemia
- Auer road = myeloblastic cancer e.g. AML; Faggot cells (clustered auer rods) = APML
- Atypical lymphoctosis –* Infective mononucleosis*, viral or autoimmune diseases
Marrow exam
- Indication
- Site of sampling
- Tests
- Contraindication
Indication: Unexplained cytopenia/ leukocytosis
Site: PSIS, ASIS or Sternum
Samples:
Trephine biopsy for histological exam
IHC for immunophenotyping;
Aspirate for flow cytology and genetic studies
Contraindication: Severe bleeding disorders (e.g. hemophilia, DIC)
Blood cytochemistry test
- Function
- Technique
Detection of Myeloid lineage with dye: Myeloperoxidase, Sudan Black B stain
No good marker for lymphoid lineage
Blood immunophenotyping
- Function
- Methods
Function: Determine cell lineage by detection of antigens on cells-of-interest
Methods:
- **Immunohistochemistry (IHC) **on trephine biopsy: one marker only
- **Flow cytometry **on peripheral blood, marrow aspirate: co-expression of multi-markers and clonal populations of abnormal WBCs Markers
Myeloid lineage: myeloperoxidase, CD117, CD13, CD33
Lymphoid lineage:CD19, CD79a, CD22 (for B-ALL), CD3 (for T-ALL)
E.g. marker CD5 expression in CLL or Mantle cell lymphoma is rarely expressed in normal cells
Blood cytogenetic workup
Function
Methods
Function
- Diagnostic: eg. t(9;22) for CML, t(15;17) for APML
- Prognostic, eg. t(8;21) in AML carries good prognosis
- Selection of treatment, eg. allogeneic HSCT
Methods:
- Karyotyping: by use of Giemsa stain
- FISH: by use of fluorescence probes to detect specific DNA sequences
Blood Molecular genetic workup
Function
Methods
Function: Detect specific mutations in genes for diagnosis, prognostication, selection of Tx
Methods:* PCR-based,* next-generation sequencing
Leukopenia
Cut-off for Neutropenia and Lymphopenia
Severity cut-offs for Neutropenia
Neutropenia:** Absolute neutrophil count (ANC) <1.5**×109/L
Severity: 1-1.5 (mild), 0.5-1 (moderate), <0.5 (severe), <0.2 (agranulocytosis)
Lymphopenia: Absolute lymphocyte count (ALC) <1×109/L
Ddx Neutropenia + following PBS results
- Toxic granules (Dohle bodies)
- Bilobed/dysplastic neutrophils
- Hypersegmented neutrophils
- Blasts
- Leukoerythroblastic pattern
Toxic granules (Dohle bodies) → sepsis
Bilobed/dysplastic neutrophils → MDS
Hypersegmented neutrophils → megaloblastic anemia
Blasts → acute leukemia
Leukoerythroblastic pattern → marrow infiltration by primary MF or metastatic bone CA
Workup tests for Lymphopenia
Check HIV status
Lymphocyte function workup:
- IgGAM for Ig levels
- Lymphocye proliferation tests
- CXR for** thymus**
- CBC/PBS for lymphocyte sub-populations
Pancytopenia
Define cut-off for lineages
2 main pathological processes
Pancytopenia: ↓ in all peripheral blood lineages (Hb <12, ANC <1.8, PLT <150)
- Bone marrow failure: Bone Marrow infiltration/ replacement; Bone Marrow Failure
- Increase consumption: Peripheral consumption or Hypersplenism
Causes of Bone marrow failure
Congenital BM failure syndromes: Schwachman-Diamond syndrome, Fanconi anaemia, dyskeratosis congenita
Aplastic anaemia: idiopathic, secondary to drugs, A/I disorders, toxins…
Nutritional: alcoholism, megaloblastic anaemia
Infection-related marrow suppression: viral infection, eg. HIV, hepatitis, EBV
Haemophagocytic lymphohistiocytosis (HLH) due to genetic causes or secondary causes, eg. EBV infection, Kawasaki disease, macrophage-activation syndrome in A/I diseases
Myelodysplastic syndrome (classically pancytopenia in elderly)
Drug myelosuppression
Causes of peripheral consumption of blood cells
DIC: sepsis, APML, other disseminated malignancies
Thrombotic microangiopathy: TTP, HUS (usually just anaemia + thrombocytopenia)
Autoimmune-related: SLE
Paroxysmal nocturnal haemoglobinuria (acquired aplastic anaemia)
Causes of hypersplenism
Vascular from cirrhosis, pre-hepatic and post-hepatic congestion
Haematological malignancy, esp CML, MF
Hemoglobinopathies: β-thal intermedia/major, HbH disease
Autoimmune cytopaenia: ITP, AIHA
Infections: Malaria, EMV, CMV, HIV
Felty syndrome from RA
Leukemia”
- Cell of origin
- Classification/ types
- S/S
Leukemia: clonal malignant disorders of haematopoietic stem cell
Classification: acute (from immature cells) vs chronic (from mature cells)
□ Acute lymphoblastic leukaemia (ALL)
□ Acute myeloid leukaemia (AML)
□ Chronic lymphocytic leukaemia (CLL)
□ Chronic myeloid leukaemia (CML)
Clinical features:
□ Constitutional symptoms: Fever
□ Marrow suppression: anemia, thrombocytopenia S/S
□ **Organ enlargement **and tissue infiltration: Gum hypertrophy, Hepatosplenomegaly, Lymphadenopathy, Mediastinal mass, Testicular hypertrophy…
□ Asymptomatic unexplained increase in cell count
Approach to diagnose Leukemia”
5 steps to diagnosis of haematological malignancy (MCICM)
□ Morphology: peripheral blood smear (number, morphology, blasts), BM aspirate and trephine
□ Cytochemistry: MPO/Sudan black B for myeloid, no marker for lymphoid
□ Immunophenotyping: flow cytometry (peripheral blood, marrow aspirate), IHC (trephine only) for cell surface marker expression
□ Cytogenetics: karyotyping, FISH for chromosomal abnormalities
□ Molecular genetics: PCR, sequencing for genetic mutations
Acute leukaemia”
Clinical features
Diagnostic feature
Features of marrow failure
→ Anaemia: general fatigue, pallor, weakness
→ Leukopenia: frequent infections
→ Thrombocytopaenia: easy bruising, gum bleeding
- Severe bleeding is suggestive of APML → should look for lab evidence of DIC
Fever: usu due to infections (instead of tumour fever → more common in APML or ALL)
Organomegaly/ Cutaneous/gum involvement
Key diagnostic finding: >20% blasts in bone marrow or peripheral blood samples
First line investigations to diagnose Acute Leukemia”
□ CBC + differential WBC + manual count
□ PBS
□ Clotting profile, D-dimer, Fibrinogen (esp DIC in APL)
□ Biochemistry for TLS: RFT, Phosphate, Calcium, K, Urate, LDH
Bone marrow aspirate/biopsy - full workup MCICM
□ Morphology
□ Cytochemistry: MPO, Sudan Black B staining (suggestive of myeloid origin)
□ Immunophenotyping: distinguishing between cell lines
□ Cytogenetics (karyotyping, FISH)
□ Molecular genetics
Pre-treatment tests for acute leukaemia”
□ CXR - disease related complications, infections
□ LDH, urate, RFT, electrolytes: baseline for possible Tumor-lysis syndrome
□ Type and crossmatch for possible future transfusion
□ D-dimer, fibrinogen, Clotting profile if suspicious of APL or DIC
□ G6PD status: C/I many haematological drugs
→ Eg. septrin for PCP prophylaxis, rasburicase for TLS prophylaxis, co-trimoxazole
□ HBsAg, anti-HBc, anti-HBs ± HBV DNA, Anti-HCV: **Hepatitis B,C status **
□ Anti-HIV Ab: **HIV status **
□ HLA typing - candidates for HSCT
General management for acute leukaemia”
- Support
- Sepsis
- TLS
- Leukostasis
Support: nutrition, antiemetic, analgesia, reverse isolation, face mask, hand hygiene, low bacteria diet
→ RBC transfusion (anaemia)
→ PLT transfusion if PLT ≤10 or ≤20 if fever/bleeding
→ FFP if bleeding due to DIC
Sepsis/ neutropenic sepsis: workup source, resuscitate, empirical broad sepctrum antibiotics, antifungal prophylaxis
TLS: hydration + allopurinol or febuxostat or rasburicase
Leukostasis : Urgent leukopheresis
- APML: ATRA +/- As2O3
Phases of acute leukaemia treatment
-
Induction phase:High intensity chemotherapy, require intensive care for severe BM hypoplasia
2.Consolidation phase: multiple courses of chemo., require supportive care for BM hypoplasia
+ Maintenance phase: Low intensity chemo. for ALL ONLY
+ CNS prophylaxis against infiltration for ALL ONLY
HSCT for refractory/ poor prognosis
AML
Epidemiology
Risk factors
Pathogenesis (/)
Epidemiology: most common (80%) acute leukaemia in adults
Demographics: median age at dx ~65y, M>F = 5:3
Risk factors: characteristically a/w
□ Genetics: a/w** impaired DNA repair**, eg. trisomy 21, Fanconi anaemia, Bloom’s syndrome…
□ Environmental exposure a/w genetic mutation, eg. chemotherapy/RT-related, chemical exposure (eg. benzene)
□ Prior pre-leukemic conditions, eg. MDS, MPN
Pathogenesis: “two hit hypothesis”
□ Class I mutation: confer proliferative advantage (FLT3-ITD, c-Kit, Ras)
□ Class II mutation: impair haematopoietic differentiation (CEBPA)
6 subtypes of AML (/)
AML with recurrent genetic abnormalities (blast cells (even if <20%) with specific leukaemia-associated cytogenetic/molecular genetic abnormalities)
AML with myelodysplasia-related changes: features of dysplasia in at least 50% cells in ≥2 lineages
Therapy-related myeloid neoplasm (t-AML): AML mutation + previously treated by drugs (eg. etoposide, alkylating agent)
AML, not otherwise specified: absence of cytogenetic abnormalities
Myeloid sarcoma: solid tumor with myeloid blast cells, mostly extramedullary disease
Myeloid proliferation related to Down syndrome
Clinical presentation of AML
2 Complications
General fatigue
S/S of BM failure: profound anaemia, thrombocytopaenia, neutropenia
DIC in promyelocytic vatiant (APML)
Gum hypertrophy/infiltration + skin + CNS involvement in myelomonocytic and monocytic subtypes
Fever: infection
Complications:
Neutropenic fever: infection due to neutropenia
Leukostasis: due to very high blast count >300
»> respiratory symptoms (SOB, hypoxia), neurological (visual changes, headache, dizziness, tinnitus…)
AML
Typical results in CBC, PBS
CBC
NcNc anaemia and thrombocytopaenia
Leukocytosis or leukopenia
PBS
Circulating myeloblast ± Auer rods
AML”
Typical results in MCICM workup
Marrow
Hypercellular with replacement by myeloid blasts
Cytochemistry
Myeloperoxidase +ve (dark staining), Sudan Black B +ve
Immuno- phenotyping
Flow cytometry: expression of CD34, HLA-DR, CD117, CD13, CD33 (varies with AML subtypes)
Cytogenetics
- t(8;21)(q22;q22) + RUNX1-RUNX1T1
- inv(16)(p13.1q22) or t(16; 16)(p13.1;q22) + CBFB-MYH11
- t(15;17)(q24.1;q21.1) + PML-RARA (diagnostic of APL)
Molecular genetics
Eg. FLT3 mutation → predicts prognosis
Diagnostic criteria of AML (/)
1 of:
→ ≥20% blast in peripheral blood or BM aspirate
→ AML-defining genetic abnormalities
- t(8;21)(q22;q22) + RUNX1-RUNX1T1
- inv(16)(p13.1q22) or t(16; 16)(p13.1;q22) + CBFB-MYH11
- t(15;17)(q24.1;q21.1) + PML-RARA (diagnostic of APL)
→ Myeloid sarcoma
PLUS demonstration of myeloid lineage in leukaemic cells
D/dx AML
MDS, MDS/MPN: blast count may be marginal (i.e. approaching 20%)
ALL: some ALL cells may co-express myeloid markers or even be mixed phenotype acute leukaemia
Vitamin B12¸folate deficiency: pancytopenia, mimic erythroleukaemia
CML in blastic crisis
AML “
Phases of treatment and treatment options
-
Induction phase: intensive therapy aiming for complete remission
* 7+3 regimen: 7d cytarabine infusion + 3d IV Daunorubicin
* Add targeted therapy e.g. FLT3 inhibitor Midostaurin for FLT3 mutant -
Consolidation phase
* High dose cytarabine (IDAC) -
Salvage phase: for refractory or relapse
* FLAG-IDA = fludarabine + cytarabine + idarubicin
* MEC = mitoxantrone + etoposide + cytarabine
* Allogeneic HSCT
APML”
Diagnostic feature
S/S
Acute promyelocytic leukaemia: biologically and clinically distinct variant of AML
□ Characterized by t(15;17)(q24.1;q21.2);PML-RARA
Clinical features:
S/S of BM failure (profound anaemia, thrombocytopaenia, neutropenia), DIC-related coagulopathy: severe bleeding, thrombotic complications
Investigations for APML”
Peripheral blood: leukopenia
Circulating malignant promyelocytes:
→ Morphology: violet granules ± bundles of Auer rods (‘faggot cells’)
→ Immunophenotype: MPO+, CD13+, CD33+
→ Genetics: t(15;17)(q24.1;q21.2);PML-RARA
APML management”
Phases and treatment options
Induction therapy:
→ All-trans retinoic acid (ATRA) + arsenic trioxide (ATO) for low risk or + conventional chemo (cytarabine + daunorubicin) for high risk
Supportive care:
→ Coagulopathy: platelet + FFP transfusion
→ Differentiation syndrome: dexamethasone as prophylaxis
Consolidation therapy:
→ ATO + ATRA or Anthracycline + ATRA
MoA of ATRA and ATO (/)
Indication in Tx of APML
□ All-trans retinoic acid (ATRA): induces differentiation and apoptosis of leukemic cells
→ Usu in combination w/ chemo (anthracycline eg daunorubicin, ± cytarabine) for induction therapy
□ Arsenic trioxide (ATO): induces apoptosis of leukemic cells
→ Can be used in induction, maintenance, and relapsed cases
ALL”
Epidemiology
Types
most common cancer (~25%) in children, most at 2-5y/o
RFs: majority idiopathic, genetic factors
Types:
- precursor lymphocytes of B, T or NK lineage :B-ALL, T-ALL, NK-ALL
- Lymphoblastic lymphoma (LBL)when presenting with lymphatic tissue involvement
Clinical features of ALL”
Constitutional symptoms: fever, weight loss, night sweats
S/S of marrow failure: anaemia, neutropenia, thrombocytopenia
Hepatosplenomegalyand lymphadenopathy
S/S of organ infiltration: important
→ Bone marrow: bone tenderness
→ CNS: meningism, headache, N/V
→ Testis: painless testicular enlargement
→ Mediastinum mass (esp. T-ALL): SVCO, upper airway obstruction
ALL
Typical CBC, PBS, Marrow exam results “
CBC:
NcNc anaemia (of variable severity) and thrombocytopaenia
WBC: Variable lymphoblasts
PBS
Circulating lymphoblast: Large, heterogenous basophilic cytoplasm
(NO granules, vacuolation, Auer rods)
Marrow and tissue section
Hypercellular marrow infiltrate with lymphoblasts
Cytochemistry
Myeloperoxidase –ve (lineage-defining)
Phenotyping
Flow cytometry: expression of B, T, NK cell lineage markers, Terminal deoxynucleotidyl transferase (TdT) expression
Cytogenetics and Molecular genetics for Prognosis and Classification only (not diagnostic)
Diagnostic criteria of ALL “
presence of lymphoblasts >20% in peripheral blood, BM or involved tissue
diagnostic morphology and immunophenotype demonstrating** lymphoid lineage**
D/dx ALL
AML
Burkitt Lymphoma
Other lymphoproliferative disorders
Reactive lymphocytosis
Treatment of ALL”
Phases, drugs used
Induction phase:
- Combination chemotherapy: vincristine + steroid + anthracycline
± rituximab for CD20+ ALL, BCR-ABL1 TKI for Ph+ ALL
- CNS prophylaxis: Methotrexate or cranial irradiation
Consolidation therapy:
* Low risk: Consolidation chemotherapy ± TKI
* Intermediate risk: Autologous HSCT
* High risk: Allogeneic HSCT
Maintenance therapy
* TKI monotherapy for Ph+ ALL
* Maintenance chemotherapy for Ph- ALL: MTX, 6MPO, Vincristine, steroid
CML “
Epidemiology
Risk factor
Defining feature
Epidemiology: 15-20% of leukaemias in adults
RF: exposure to ionizing radiation
Pathogenesis: considered a type of MPN, defined by BCR-ABL1 fusion gene due to Philadelphia chromosome (t(9;22))
Clinical features of CML “
Asymptomatic, non specific Constitutional symptoms: LOW, LOA, night sweats
Anaemia and platelet dysfunction (usu. Thrombocytosis)
Massive splenomegaly→ early satiety and LUQ pain
CML
3 phases of disease course”
Chronic phase (3-4y): relatively indolent disease with minimal symptoms
Acceleration phase (18mo): 10-19% blasts in PBS/BM, basophils ≥20%, PLT <100 or >1000, progressive splenomegaly
Blastic crisis (1-2mo): acute leukaemia-like picture with >20% blast
CML “
Typical CBC, PBS, Marrow exam results (morphology, cytochemistry, cytogenetics)
CBC
- Bimodal distribution of neutrophil and myelocyte: Basophilia, monocytosis and eosinophilia
- NcNc anaemia (45-60%),
- PLT normal or thrombocytosis
PBS: Morphologically normal leukemic cells
Marrow
- Morphology: granulocytic hyperplasia, dwarf megakaryocytes with hypolobulated nuclei
- Cytochemistry
Low leukocyte alkaline phosphatase (LAP) score
- Cytogenetics
Ph chromosome t(9;22) on karyotyping (90-95% +ve), BCR-ABL1 fusion gene on FISH
Ddx to CML
Leukaemoid reaction to infection (should have ↑LAP score, toxic granulation)
Other chronic myeloid neoplasm: MDS, MPN, MDS/MPN
‘Atypical CML’: so-called BCR-ABL1-negative CML
Other Ph-positive malignancies: minority of ALL, AML
Treatment of CML”
Chronic phase:** BCR-ABL TKI inhibitor**
→ Imatinib [1G] for low-risk, **nilotinib/ desatinib **[2G] for high-risk
Accelerated phase: induction TKI + HSCT
Blastic phase:
→ Lymphoid crisis: treat as Ph+ ALL
→ Myeloid crisis: induction TKI + HSCT
CLL
Pathogenesis (/)
Pathogenesis:
arise from progression from monoclonal B cell lymphocytosis (common in elderly)
□ Consist of clonal B cells arrested in some stage between pre-B and mature B cells with arrested apoptotic mechanisms → accumulation in blood and lymphoid tissues
Can also originate from relatively mature B lymphocytes
→ CLL if cytopenia due to BM infiltration
→ SLL if LN, splenic or other extramedullary involvement
Clinical features of CLL”
Asymptomatic (>80%): absolute lymphocytosis
Non-specific **B symptoms **(5-10%):
→ Unintentional weight loss
→ Fever: >38oC for ≥2w w/o evidence of infection
→ Drenching night sweats w/o evidence of infection
→ Extreme fatigue
Generalized lymphadenopathy (50-90%): esp. cervical, supraclavicular, axillary
Mild hepatomegaly/ splenomegaly/ both
Skin infiltration: esp at face
Complications of CLL”
Immunodeficiency: cell-mediated + humoral immunity impaired due to lymphocyte dysfunction
Anaemia: due to AIHA, marrow infiltration or hypersplenism
Thrombocytopenia: due to ITP, marrow infiltration or hypersplenism
CLL
Typical findings in CBC, Immunoglobulin tests, PBS, Bone marrow exam “
CBC
* Clonal Lymphocytosis: >5×109/L B lymphocyte count
* Cytopenia for any lineage
Ig Tests:
* **Hypogammaglobulinaemia **(~25%): usually all three Ig classes
* High LDH and b2-microglobulin
BM exam:
* Lymphocyte infiltration, Richter’s transformation to large cell lymphoma
D/dx CLL (/)
Infectious causes of lymphocytosis (non-clonal, under 3 months)
Other chronic lymphoproliferative diseases:
- Prolymphocytic leukaemia
- Mantle cell lymphoma
- Lymphoplasmacytic lymphoma
- Hairy cell leukaemia
- Follicular lymphoma
CLL staging (/)
Treatment for CLL “
Watchful waiting if asymptomatic or very old
- Targeted therapy:
Ibrutinib, Acalabrutinib: inactivation of BTK protein leading to B cell apoptosis -
Fludarabine-based regimen for young patients
» Fludarabine, cyclophosphamide, rituximab -
Chlorambucil-based for old patients
» chlorambucil ± rituximab
HSCT: as salvage therapy in selected young patients
List Hematological emergencies of leukemia “
Neutropenic Fever
Septic shock
Tumor lysis syndrome
Hyperleukocytosis and Leukostasis
DIC in APL
Neutropenic fever”
Definition
Pathogenesis
Neutropenia: ANC ≤1×109/L
Fever: pyrexia >38.3oC
Pathogenesis:
- Neutropenia: caused by malignant infiltration of marrow or Chemotherapy
- **Infection of GI, aero-digestive tract, skin **(from catheter)
→ G+ bacteria: use of indwelling catheters
→ G- bacilli: commonest, eg. Pseudomonas aeruginosa
→ Fungal: prolonged neutropenia
→ Others: viral reactivation (eg. Hep B, HSV), TB
Clinical presentation of Neutropenic fever “
Workup
Clinical features: subtle due to diminished inflammatory repsonse
□ Fever: often the only presenting sign
□ Localizing S/S to GI, Skin, Respiratory tract
Workup:
□ Assess localizing S/S for infection, sepsis and shock
Broad septic workup:
blood, sputum, urine culture and sensitivity testing
CXR ± other specimens (eg. LP)
Management of Neutropenic fever “
IV Empirical, broad-spectrum Abx
low-risk, i.e. neutropenia ≤7d + no or few other comorbidities
- Ciprofloxacin+ augmentin/ levofloxacin
high-risk, i.e. ANC ≤0.1 for >7d, shock, pneumonia, newly onset abdominal pain or CNS signs
- 3/4G cephalosporins: Ceftazidime or Cefepime
- Tazocin or sulperazon
- Imipenem or meropenem
(+/- Aminoglycoside, Vancomycin, Amphotericin B if needed)
No response:
G-CSF
Buffy coat (WBC) transfusion
Fluid resuscitation, inotropes
Tumor lysis syndrome”
Causes
Features and S/S
lysis of tumors cells from rapidly proliferating (and drug-sensitive) neoplasm
Causes:
* After cytotoxic chemotherapy
* spontaneously (auto-TLS)
* High grade neoplasm with high tumor burden
Result: PAN-HIGH except calcium
→ HyperK, hyperPO4, hyperuricaemia, High LDH
→ Metabolic acidosis (lactate)
S/S
→ HypoCa: confusion, arrhythmia, tetany, seizure, sensory loss (CATS)
→ AKI (uric acid nephropathy and acute nephrocalcinosis)
Management of TLS”
Tx:
Aggressive hydration
Correction of hyperK + ECG monitoring
Rasburicase (recombinant urate oxidate)
allopurinol/febuxostat (xanthine oxidase inhibitor)
Renal replacement therapy/ Hemodialysis
Hyperleukocytosis and Leukostasis”
Cause
Pathophysiology
□ Hyperleukocytosis: very high WBC
□ Leukostasis: very high blast cell count causing stasis in microcirculations, decrease tissue perfusion
Cause: leukemias with large, poorly deformable blasts
Pathophysiology:
□ Blast cells are less deformable than mature cells → plugs in microcirculation
□ High metabolic activity with cytokine production → endothelial damage
Clinical presentation and management of Hyperleukocytosis and Leukostasis”
S/S:
□ Neurology: headache, dizziness, tinnitus, gait instability, confusion, coma
□ Pulmonary (~30%): dyspnoea, hypoxia ± diffuse interstitial/alveolar infiltrates on CXR
□ CRV thrombosis: acute blindness
□ MI, AKI, priapism, acute limb ischaemia, ischaemic bowel
Mx:
□ Urgent Cytoreduction: induction chemotherapy, hydroxyurea or leukapheresis
□ hydration: to prevent TLS
Indication for Allogeneic HSCT”
Haematological malignancies:
* AML/ALL/ CML/ CLL
* MDS/ MPN
* Lymphoma
Non-haematological:
* Neuroblastoma
Non-malignant marrow disorders:
* Severe aplastic anemia - Fanconi, Blackfan-Diamond, Wiskott-Aldrich
* Congenital BM failure
* Severe haemaglobinopathies: Sickle cell anemia, Thal. major
* Primary immunodeficiency - SCID
* IEM
Indication for Autologous HSCT”
Disorders that do not primarily involve haemopoietic stem cells:
Multiple myeloma (MM)
Waldenström macrogloblinemia
Lymphoma
Amyloidosis
Testicular germ cell tumour
How does HSCT cure leukemia “
- Eradicate leukaemia cells with high dose chemotherapy and radiotherapy
- Replace diseased BM with healthy marrow from normal donor
- Graft versus Leukaemia effect
Donor selection criteria for HSCT”
Sources of donors
Human leukocyte antigen (HLA) matching: Determines risk of graft-versus-host disease in HSCT
- Syngeneic: from MZ twin → by definition 12/12 matched, no GVHD
- Matched sibling donor (allogeneic): 6/6 matched (HLA-A, -B, -DR)
- Matched unrelated donors: 8/8 matched (HLA-A, -B, -C, -DR)
- Mismatched related donors: <6/6 matched,
- Single antigen mismatched siblings (5/6) or Haploidentical donors (3/6)
unrelated donors from HK BM Donor Registry pool
Haploidentical donor - from ANY sibling, parent, child ± other relatives
ABO incompatibility doesn’t matter
Acute complications of HSCT”
Chemo causing Cytopenia:
* Hemorrage, Anaemia
* Neutropenic infection/ sepsis
* mucositis
* Veno-occlusive disease (VOD) of liver
HSCT:
* Graft rejection (host-versus-graft)
* Acute graft-versus-host disease (acute GVDH)
Chronic/Long-term complications of HSCT
Cardiovascular disease from cardiotoxic drug - main death cause
From long-term immunosuppression:
Endocrine dysfunction: T2DM, hypothyroidism, hypogonadism and Infertility, Osteoporosis
Second malignancy: relapse, PTLD, Post-treatment MDS, Acute leukemia, Solid tumors
Cataracts from irradiation
Chronic GVHD
Allogeneic HSCT vs Autologous HSCT”
differences?
Allogeneic HSCT:
* Donor HSC (related or unrelated) harvested > Conditioning myeloablative therapy > donor HSC infusion to rescue from marrow aplasia
* Graft-versus-leukemia (GvL) effect
* Immunosuppression against Graft-versus-host-disease (GVHD)
Autologous HSCT:
* Own HSC harvested and cryopreserved > Conditioning myeloablative therapy > re-infusion of autologous HSC to rescue from marrow aplasia
Methods to harvest haematopoietic stem cells”
Bone marrow harvest:
- aspirated from posterior iliac crests under regional/general anaesthesia
Peripheral blood progenitor cell (PBPC):
- G-CSF 3 days prior to harvest → mobilize BM HSC into peripheral blood (1000×)
- peripheral blood for apheresis to isolate PBPC
Umbilical cord blood (UCB):
- esp for children due to small volume
Bone marrow harvest vs Peripheral blood progenitor cell for HSCT (/)
Advantages and Disadvantages
Myeloablative conditioning”
Indication
Function
Drug options
Indication: Before HSCT
Function: High dose Chemotherapy +/- radiotherapy
- Eradicate malignancy/ residual leukemia
- Immunosuppression for engraftment, prevent graft rejection
Drugs:
- Cyclophosphamide
- Busulfan
- Fludarabine
Radiation: Total Body Irradiation
HLA (/)
- Gene locus
- Function
- MHC classes and function
- Role in transplant
Location: major histocompatibility complex (MHC) locus at 6p
Function: peptide-binding to present antigens to and activates T cells
□ MHC class I: includes HLA-A, -B, -C
→ Expressed on all nucleated cells
→ Binds CD8+ T cells to activate cell-mediated immunity
→ Generally determines risk of graft rejection
□ MHC class II: includes HLA-DP, -DQ, -DR
→ Expressed on professional antigen-presenting cells
→ Binds CD4+ T cells to activate humoral immunity
→ Generally determines risk of graft-versus-host disease
□ Role in transplantation:
→ Determines risk of graft rejection in solid organ transplant → matching is preferred but can theoretically be overcome by immunosuppressant use
→ Determines risk of graft-versus-host disease in HSCT → matching is critical
Acute GVHD (/)
Pathogenesis
S/S
Treatment
Pathogenesis:
- donor T cell recognize host cells (HLA) as foreign → graft-vs-host reaction
- >>> inflammatory T cell infiltrate with tissue destruction and apoptosis
S/S:
- Skin rash (pruritic/painful erythematous MP rash becoming confluent ± bullous TEN-like lesions)
- Gastrointestinal symptoms: Diarrhea, Abdominal pain
- Liver disease: painful hepatomegaly, obstructive jaundice S/S
Treatment:
- immunosuppression (CNI + MTX/MMF) ± T cell depletion (ATG)
- Topical steroids/ Tacrolimus/ Anti-histamines
- IV or oral steroid if GI symptoms
- Immunosuppressants (MMF, Sirolimus, Etanercept) or steroids
Chronic GVHD (/)
Definition
Pathogenesis
S/S
Treatment
defined as symptoms develop >100d of HSCT
Pathogenesis:
- donor T cell recognize host cells (HLA) as foreign → graft-vs-host reaction
- → early inflammation with tissue injury progressing to fibrosis without much infiltrate in late stages
S/S:
- Skin rash (Lichen planus-like, Sclerotic, asso. nail dystrophy, scarring/non-scarring alopecia…)
- Mucositis: Ocular, Oral, GI at esophagus and bowels, Genital
- Liver: deranged LFT
- Lung: Bronchiolitis obliterans
- MSS: fasciitis, myositis
Treatment:
- Local treatment if mild disease only, eg. oral hygiene, topical steroids, endoscopic dilation, O2
- Systemic treatment if moderate/severe disease >> Prednisone ± CNI
