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Bone Marrow Failure/ Aplastic Anemia

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Title: Bone Marrow Failure/ Aplastic Anemia


1
Bone Marrow Failure/ Aplastic Anemia
  • Dr. MERVAT A.HESHAM
  • 2008

2
What is Aplastic Anemia?
  • Aplastic Anemia is a bone marrow failure
    disease.


Bone marrow is a Factory of Blood Cells
Red Blood Cell
Platelets
White Blood Cell
Help to save a Life
www.aaaoi.org
3
Aplastic Anemia patients
  • Aplastic Anemia patients have decreased amounts
    of - Red Blood Cells
  • - White Blood Cells
  • - Platelets

Help to save a Life
www.aaaoi.org
4
Functions of Blood Cells
  • Red Blood Cells
  • Carry oxygen to all body organs
  • White Blood Cells
  • Fight infection and keep you healthy
  • Platelets
  • Help control bleeding

Help to save a Life
www.aaaoi.org
5
Symptoms
  • Low Red Blood Cell
  • Fatigue, Headache, Inability to Concentrate
  • Low White Blood Cell
  • Viral Infections, Bacterial Infections
  • Low Platelets
  • Easy Bruising, Nosebleeds, Petichiae

Help to save a Life
www.aaaoi.org
6
DEFINITION
  • A disorder of the hemtopoietic system
    characterized by
  • Bone marrow - marked reduction of all 3 cell
    lines
  • Peripheral blood - pancytopenia

7
PATHOGENESIS
  • Stem cell failure resulting from
  • 1-An acquired intrinsic stem cell defect
  • 2-An environmental cause
  • Immune mechanisms
  • Growth factor deficiency
  • Defects in the microenvironment

8
Epidemiology
  • Incidence 5-10106 per year
  • Age 15 30 years
  • gt 60 years
  • Sex M F

9
Etiology
  • Hereditary
  • 1-Schwacman Diamond
  • 2-Fanconis anemia syndrome
  • 3-Dyskeratosis congenita
  • Acquired
  • 1-Idiopathic
  • 2- Drugs dose related
  • idiosyncratic
  • 3-Radiation
  • 4-Chemicals
  • 5-Viruses
  • 6-Pregnancy
  • 7-PNH
  • 8-Disorders of immune system

10
Clinical manifestations
  • Insidious onset
  • Manifestations caused by pancytopenia
  • Anemia - weakness, fatigue
  • Thrombocytopenia bleeding
  • Neutropenia - infections

11
Diagnosis
  • Peripheral blood
  • Pancytopenia
  • Normocytic-normochromic anemia
  • Low reticulocyte index
  • Bone marrow biopsy
  • Empty fatty spaces
  • Few hematopoietic cells
  • Lymphocytes and plasma cells

12
Bone Marrow Failure
  • Congenital/ Syndromic
  • Acquired

13
Acquired Aplastic Anemia
14
Acquired Aplastic Anemia
  • Secondary
  • Idiopathic

15
Secondary AA
  • 1-Meds/ toxins
  • Chemo
  • Chloramphenicol, benzene,
    carbamazapine, indomethacin, cimetidine,
    sulfas, acetazolamide, lithium
  • 2- Radiation
  • 3-Viruses - EBV, HIV, parvo, hepatitis

16
  • 4-Paroxysmal Nocturnal Hemoglobinurea
  • 5-Malnutrition
  • 6-Myelodysplastic syndromes
  • 7-Thymoma

17
PATHOPHYSIOLOGY
  • Direct toxic injury to hematopoietic stem cells
    can be induced by exposure to
  • ionizing radiation, cytotoxic chemotherapy, or
    benzene. These agents can crosslink
  • DNA and induce DNA strand breaks leading to
    inhibition of DNA and RNA synthesis.

18
  • 2-Immune-mediated destruction of hematopoietic
    stem cells
  • -- Direct killing of the stem cells has been
    hypothesized to occur via interations between Fas
    ligand expressed on the T-cells and Fas (CD95)
    present on the stem cells, which triggers
    programmed cell death (apoptosis).
  • -- T-lymphocytes also may suppress stem cell
    proliferation by elaborating soluble factors
    including interferon-?.

19
  • -T cells from aplastic anemia patients secrete
    IFN-ã and tumor necrosis factor (TNF).
  • -IFN-ã and TNF are potent inhibitors of both
    early and late hematopoietic progenitor cells .
  • -Both of these cytokines suppress hematopoiesis
    by their effects on the mitotic cycle and, more
    importantly, by the mechanism of cell killing.
  • -Activation of the Fas receptor on the
    hematopoietic stem cell by the Fas ligand present
    on the lymphocytes leads to apoptosis of the
    targeted hematopoietic progenitor cells.

20
  • Cytotoxic T cells also secrete interleukin-2
    (IL-2), which causes polyclonal expansion of the
    T cells.
  • IFN-ã also induces the production of the toxic
    gas nitric oxide, diffusion of which causes
    additional toxic effects on the hematopoietic
    progenitor cells.

21
Suppress proliferation
with ligand, signals apoptosis
Young NEJM 1997
22
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23
Idiopathic AA
  • 70 or more of cases
  • Higher in SE Asia
  • M F

24
AA - Clinical
  • Symptoms are due to pancytopenia
  • pallor, mucosal bleeding, ecchymoses, or
    petechiae and bacterial or fungal
  • infections..
  • Hepatosplenomegaly and lymphadenopathy do not
    occur their presence suggests
  • an underlying leukemia.
  • Hyperplastic gingivitis is also a symptom of
    aplastic anemia.

25
AA - Labs
  • No RBC pale, tachycardic
  • No plt bruising, bleeding
  • No WBC infection
  • Retic lt 1
  • Plt lt 20,000
  • ANC lt 500

26
AA - Labs
  • Marrow lt 25 cellularity

27
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28
AA - Evaluation
  • CBC w/ diff and retic
  • Bone marrow
  • Send DEB (Fanconis test)
  • Send Hep A, B, C, D titers HIV
  • Test for PNH (CD55, CD59)
  • HLA typing
  • Fetal hemoglobin
  • Liver and renal function chemistries

29
  • Quantitative immunoglobulins, C3, C4, and
    complement.
  • Autoimmune disease evaluation Antinuclear
    antibody (ANA), total hemolytic complement
    (CH50), Coombs test.
  • HLA typing Patient and family done at the time
    of diagnosis of severe aplastic anemia to ensure
    a timely transplant.

30
CLASSIFICATION
Designation Criteria Criteria
Peripheral blood BM biopsy
Severe aplastic anemia -2 / 3 values- Neutrophils lt 500/mL -Platelets lt 20,000/ ul- -Reticulocyte index lt 1 -Marked hypocellular lt 25 cellularity -Moderate hypocellular lt25-50 -normal cellularity with lt30 of remaining cell hematopoietic
Very severe aplastic anemia As above but neutrophils lt 200/mL Infection present
31
Treatment Options
Bone Marrow Transplant
Growth Hormones
Immune Suppressive Therapy
Supportive Care
Help to save a Life
www.aaaoi.org
32
TREATMENT
  • 1-Withdrawal of the etiologic agent
  • 2-Supportive treatment
  • Blood and platelet transfusion used with caution-
    sensitization (filtered)
  • 3-Allogeneic BMT
  • -Preferably from sibling
  • -Curative in 60-90 of patients
  • -Applicable only for a third of patients
  • Immunosuppression
  • Cyclosporin ATG
  • Corticosteroids
  • High dose cyclophosphamide
  • G-CSF/ GM-CSF/ EPO - maybe
  • Response rate 50-70 Occurs 2-3
    months post Rx.

33
AA
  • Newer
  • Mycophenolate mofetil (MMF) - cytotoxic to T
    cells
  • Monoclonal Ab against IL-2 receptor which is
    present on activated lymphocytes

34
AA - Outcomes
  • Age, Younger is better
  • BMT
  • lt 20 yr with a sib 75
  • 20 - 40 yr with a sib60
  • lt 20 yr unrelated BMT 40
  • 20 - 40 yr unrelated BMT35
  • Immunosuppression - 60 - 80
  • But for how long and consequences

35
Fanconi Anemia
36
History Guido Fanconi
  • Fanconi Anemia (Fanconi pancytopenia syndrome)
    1927 - 3 brothers with pancytopenia and physical
    abnormalities, perniziosiforme
  • Fanconi Syndrome (renal Fanconi syndrome) 1936
    Ricketts, growth retardation, proteinuria,
    glucosuria, and proximal renal tubular acidosis

Alter, FA101 (2006)
37
Fanconi Anemia (FA)
  • Rare (lt 1/ 100,000 births)
  • Autosomal recessive
  • Many physical features
  • But up to 20-25 will have no physical findings
  • Mean age at dx 7.8 yrs

38
Autosomal Recessive Inheritance
39
FA- Clinical
Abnormality of FA Patients
Skin 60
Short Stature 57
Upper Limb Abnl 48
Head/ Microcephaly 27
Renal 23
Dev. Delay 13
None Reported 20
Short Stature Only 1
Skin Only 3
40
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41
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42
Clinical Features
Progressive bone marrow failure Most common
etiology of inherited bone marrow failure Others
include dykeratosis congenita, amegakaryocytic
thrombocytopenia, Schwachman-Diamond
syndrome Increased risk of MDS and AML
(15,000x) Many have monosomy 7, or duplication
of 1q (Auerbach et al., Cancer Genet Cytogenet
1991)
43
Clinical Features
  • Increased risk of solid tumor formation (hepatic,
    esophageal, oropharyngeal, vulvar)
  • Average age at diagnosis is 23
  • Cumulative incidence 30 by age 45

Shimamura et al., Gene Reviews 2002
(genetests.org) Alter et al. Blood 2003
44
FA - genetics
  • Identification of subtypes (compliment groups)
  • A, B, C, D1, D2, E, F, G
  • Identical clinically
  • Sub-units of a common protein/ common pathway
  • Protein modifies FANCD2
  • FANCD2 interacts with BRCA1 and 2
  • BRCA1 and 2 needed for DNA repair

45
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46
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47
PATHOPHYSIOLOGY
  • DNA damage activates a complex consisting of
    Fanconi proteins A, C, G, and F. This in turn
    leads to the modification of the FANCD2 protein.
    This protein interacts, for example, with the
    breast cancer susceptibility gene BRCA1.

48
  • Fanconi anemia cells are characterized by
    hypersensitivity to chromosomal breakage as well
    as hypersensitivity to G2/M cell cycle arrest
    induced by DNA cross-linking agents.
  • In addition there is sensitivity to oxygen-free
    radicals and to ionizing
  • radiation.

49
Diagnosis
  • -Pts. with congenital abnormalities are often
    diagnosed as neonates/infants
  • Others may be diagnosed when hematological
    problems occur
  • Median age of onset of pancytopenia is 7
  • Usually normal CBC at birth
  • First develop macrocytosis, then
    thrombocytopenia, and eventually neutropenia

50
Diagnosis
  • Based on chromosomal hypersensitivity to
    cross-linking agents
  • Chromosome fragility test Mitomycin C (MMC) or
    diepoxybutane (DEB) added to lymphoctyes
    increases the number of chromosome breaks and
    radial structures
  • Very specific for FA, regardless of severity of
    disease
  • Can do chromosome breakage analysis on amniotic
    cells, chorionic villus cells or fetal blood

51
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52
Chromosome breakage in Fanconi Anemia cells  
FA cells were treated with mitomycin C and
harvested in metaphase. Typical abnormalities
include radial formation (green circle) and
chromosome breaks (red arrows).
53
Initial management
  • Refer for genetic counseling
  • Testing of siblings
  • Renal ultrasound, hearing test, eye exam
  • Endocrine evaluation if evidence of growth
    failure (check growth hormone levels, TSH)
  • Referral to hand surgeon for radial ray defects
  • Bone marrow biopsy

54
Management
  • Bone marrow failure
  • Transfusions
  • Androgens (e.g. oral oxymethalone) can improve
    blood counts in 50 of pts.
  • Side effects Masculinization, acne,
    hyperactivity, premature closure of epiphyses,
    liver toxicity, hepatic adenomas
  • Growth factors (G-CSF, CM-CSF) should not be
    used in patients with clonal cytogenetic
    abnormalities
  • Bone marrow transplantation
  • FA cells are very sensitive to radiation and
    alkylating agents can use greatly reduced doses
  • 2-yr. survival 70 for allo 20-40 for MUD

Guardiola et al. Bone Marrow Transplant
1998 MacMillan et al., Br J Haematol 2000
55
Management - Gene therapy
  • Goal is to permanently correct hematological
    manifestations by transducing hematopoietic
    progenitor cells with a vector containing the
    deficient gene
  • Knockout mice with FANCC using retroviral
    vectors - phenotypic correction (Gush et al.,
    Blood 2000)
  • Knockout mice with FANCA and FANCC using
    lentiviral vectors more promising (integrates
    into the genome) (Galimi et al. Blood 2002)

56
Other Congenital Marrow Failures
  • Dystkeratosis Congenita
  • Rare
  • Different modes of inheritance
  • Ectodermal dysplasia
  • 50 develop aplastic anemia in midteens
  • Schwachman-Diamond
  • Cartilage-Hair Hypoplasia
  • Familial Marrow Dysfunction

57
Marrow Failure
  • Pearsons syndrome
  • Seckels syndrome
  • Amegakaryocytic Thrombocytopenia
  • Noonans syndrome

58
Marrow Failure
  • Single Cytopenias
  • -Pure Red Cell Aplasia (Diamond-Backfan)
  • -Congenital Neutropenia (Kostmanns)
    -Thrombocytopenia with Absent Radii

59
PURE RED CELL APLASIA
60
Definition
  • A syndrome characterized by
  • Normocytic normochromic anemia
  • Reticulocytopenia lt1
  • BM erythroblasts lt 0.5
  • Aplasia selective to erythroid cell line only !

61
Epidemiology
  • Relatively uncommon
  • May affect any age group but predominantly of
  • infancy and childhood
  • MF
  • No ethnic predisposition
  • Of autosomal dominant inheritance

62
Etiology Pathogenesis
  • Congenital hypoplastic anemia
  • (Diamond-Blackfan syndrome)
  • Acquired PRCA
  • Primary
  • Secondary

63
Acquired PRCA
  • Primary
  • Autoimmune
  • Preleukemic
  • Idiopathic
  • Secondary
  • Thymoma
  • Hematologic malignancies
  • Solid tumors
  • Infections
  • Chronic hemolytic anemias
  • Collagen vascular diseases
  • Pregnancy
  • Severe renal failure
  • Severe nutritional deficiencies
  • Drugs chemicals
  • Miscellaneous

64
PRIMUM NON NOCERE
65
Mechanisms of Immunologic Inhibition
  • Antibodies directed against
  • Erythropoietin
  • Erythroblasts ?
  • Cellular inhibition
  • Inhibitory T cells
  • NK cells

66
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67
Clinical Manifestations
  • Symptoms of anemia
  • The median age at presentation of anemia is 2
    months and the median age at diagnosis of DBA is
    3 months.
  • Physical anomalies, excluding short stature
  • No hepatosplenomegaly.
  • Malignant potential
  • In patients with long-standing PRCA
    transfusional hemosiderosis

68
Laboratory Evaluation
  • Diagnostic criteria
  • --Normochromic, usually macrocytic anemia,
    relative to patients age and occasionally
  • normocytic anemia developing in early childhood
  • -- Reticulocytopenia
  • -- Normal or only slightly decreased granulocyte
    count
  • -- Normal or slightly increased platelet count
  • Supportive criteria
  • -Typical physical abnormalities
  • -Increased fetal hemoglobin
  • -Increased erythrocyte adenosine deaminase (eADA)
    activity

69
  • BM
  • Absence of erythroblasts lt1 on BM
  • (absence of normoblasts, in some cases with
    relative increase in proerythroblasts or normal
    number of proerythroblasts with a maturation
    arrest).
  • normal myeloid and megakaryocytic series.
  • Usually normal karyotype, except for
    preleukemic cases

70
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71
Treatment Congenital Hypoplastic Anemia
  • Corticosteroids
  • AlloBMT
  • IL-3 experimental
  • Patients refractory to all treatments regular
    transfusions desferioxamine

72
Treatment Acquired PRCA
  • -Discontinuation of all drugs
  • -R/O infections
  • -If parvovirus suspected high dose IgG
  • -In the presence of thymoma thymectomy

73
  • -In 30-40 erythropoiesis remits within 4-8 weeks
  • -Non-responding pts. should be treated as
    primary acquired PRCA
  • -Thymectomy in the absence of thymoma is not
    recommended
  • -If an underlying disease treat the disease

74
Treatment Acquired PRCA
  • For primary or secondary PRCA not responding to
    treatment of underlying disease
  • Prednisone
  • Cyclophosphamide / azathioprine
  • Cyclosporine
  • ATG
  • High dose IgG
  • Plasmapheresis
  • Splenectomy
  • Rituximab

75
THANK YOU
76
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