Bone Marrow Failure Aplastic Anemia

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Bone Marrow Failure/ Aplastic Anemia

• Dr. MERVAT A.HESHAM
• 2008

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What is Aplastic Anemia?

• Aplastic Anemia is a bone marrow failure
  disease.

Red Blood Cell
Platelets
White Blood Cell
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3
Aplastic Anemia patients

• Aplastic Anemia patients have decreased amounts
  of - Red Blood Cells
• - White Blood Cells
• - Platelets

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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

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Symptoms

• Low Red Blood Cell
• Fatigue, Headache, Inability to Concentrate
• Low White Blood Cell
• Viral Infections, Bacterial Infections
• Low Platelets
• Easy Bruising, Nosebleeds, Petichiae

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DEFINITION

• A disorder of the hemtopoietic system
  characterized by
• Bone marrow - marked reduction of all 3 cell
  lines
• Peripheral blood - pancytopenia

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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

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Epidemiology

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

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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

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Clinical manifestations

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

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Diagnosis

• Peripheral blood
• Pancytopenia
• Normocytic-normochromic anemia
• Low reticulocyte index

• Bone marrow biopsy
• Empty fatty spaces
• Few hematopoietic cells
• Lymphocytes and plasma cells

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Bone Marrow Failure

• Congenital/ Syndromic
• Acquired

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Acquired Aplastic Anemia
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Acquired Aplastic Anemia

• Secondary
• Idiopathic

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Secondary AA

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

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

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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.

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• 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-?.

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• -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.

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• 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.

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Suppress proliferation
with ligand, signals apoptosis
Young NEJM 1997
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Idiopathic AA

• 70 or more of cases
• Higher in SE Asia
• M F

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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.

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AA - Labs

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

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AA - Labs

• Marrow lt 25 cellularity

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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

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• 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.

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CLASSIFICATION
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Treatment Options
Bone Marrow Transplant
GrowthHormones
Immune Suppressive Therapy
Supportive Care
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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.

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AA

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

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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

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Fanconi Anemia
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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)
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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

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Autosomal Recessive Inheritance
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FA- Clinical
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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)
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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
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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

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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.

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• 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.

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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

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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

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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).
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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

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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
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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)

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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

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Marrow Failure

• Pearsons syndrome
• Seckels syndrome
• Amegakaryocytic Thrombocytopenia
• Noonans syndrome

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Marrow Failure

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

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PURE RED CELL APLASIA
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Definition

• A syndrome characterized by
• Normocytic normochromic anemia
• Reticulocytopenia lt1
• BM erythroblasts lt 0.5
• Aplasia selective to erythroid cell line only !

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Epidemiology

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

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Etiology Pathogenesis

• Congenital hypoplastic anemia
• (Diamond-Blackfan syndrome)

• Acquired PRCA
• Primary
• Secondary

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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

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PRIMUM NON NOCERE
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Mechanisms of Immunologic Inhibition

• Antibodies directed against
• Erythropoietin
• Erythroblasts ?
• Cellular inhibition
• Inhibitory T cells
• NK cells

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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

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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

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• 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

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TreatmentCongenital Hypoplastic Anemia

• Corticosteroids
• AlloBMT
• IL-3 experimental
• Patients refractory to all treatments regular
  transfusions desferioxamine

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Treatment Acquired PRCA

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

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• -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

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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

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THANK YOU
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