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

Bone Marrow Failure/ Bone Marrow Failure/ Aplastic AnemiaAplastic Anemia

Bone Marrow Failure/ Bone Marrow Failure/ Aplastic AnemiaAplastic Anemia

Dr. MERVAT A.HESHAMDr. MERVAT A.HESHAM

20082008

What is Aplastic Anemia?

Aplastic Anemia is a bone marrow failure disease.

Bone marrow is a Factory of Blood Cells

Red Blood Cell

White Blood Cell

Platelets

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Aplastic Anemia patients

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

-White Blood Cells -Platelets

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Functions of Blood Cells

Red Blood CellsCarry oxygen to all body organsWhite Blood CellsFight infection and keep you healthyPlateletsHelp control bleeding

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Symptoms

Low Red Blood CellFatigue, Headache, Inability to ConcentrateLow White Blood CellViral Infections, Bacterial InfectionsLow PlateletsEasy Bruising, Nosebleeds, Petichiae

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DEFINITIONA disorder of the hemtopoietic system characterized by:Bone marrow - marked reduction of all 3 cell lines

Peripheral blood - pancytopenia

PATHOGENESISStem cell failure resulting from:

1-An acquired intrinsic stem cell defect

2-An environmental cause Immune mechanisms

Growth factor deficiency

Defects in the microenvironment

EpidemiologyIncidence: 5-10:106 per year

Age: 15 –30 years > 60 years

Sex: M = F

Etiology

Hereditary

1-Schwacman – Diamond

2-Fanconi’s anemia syndrome

3-Dyskeratosis congenita

Acquired1-Idiopathic

2 -Drugs: dose relatedidiosyncratic

3-Radiation 4-Chemicals

5-Viruses6-Pregnancy

7-PNH8-Disorders of immune

system

Clinical manifestations

Insidious onsetManifestations caused by pancytopeniaAnemia - weakness, fatigueThrombocytopenia – bleedingNeutropenia - infections

Diagnosis

Peripheral blood*Pancytopenia

*Normocytic-normochromic anemia

*Low reticulocyte index

Bone marrow biopsy

*Empty fatty spaces

*Few hematopoietic cells

*Lymphocytes and plasma cells

Bone Marrow FailureCongenital/ SyndromicAcquired

Acquired Aplastic Acquired Aplastic AnemiaAnemia

Acquired Aplastic Acquired Aplastic AnemiaAnemia

Acquired Aplastic Anemia

**Secondary

**Idiopathic

Secondary AA1-Meds/ toxins

Chemo Chloramphenicol, benzene,

carbamazapine, indomethacin, cimetidine, sulfas, acetazolamide, lithium

2 -Radiation3-Viruses - EBV, HIV, parvo, hepatitis

4-Paroxysmal Nocturnal Hemoglobinurea

5-Malnutrition6-Myelodysplastic syndromes

7-Thymoma

PATHOPHYSIOLOGYDirect toxic injury to hematopoietic stem cells can be induced by exposure toionizing radiation, cytotoxic chemotherapy, or benzene. These agents can crosslinkDNA and induce DNA strand breaks leading to inhibition of DNA and RNA synthesis.

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-γ.

-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.

*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 .

Young NEJM 1997

Suppress proliferation

with ligand, signals apoptosis

Idiopathic AA*70% or more of cases

Higher in SE AsiaM = F

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 suggestsan underlying leukemia.

**Hyperplastic gingivitis is also a symptom of aplastic anemia.

AA - LabsNo RBC = pale, tachycardicNo plt = bruising, bleedingNo WBC = infectionRetic < 1%Plt < 20,000ANC < 500

AA - LabsMarrow : < 25% cellularity

AA - Evaluation*CBC w/ diff and retic

*Bone marrow

*Send DEB (Fanconi’s test)*Send Hep A, B, C, D titers HIV

*Test for PNH (CD55, CD59)*HLA typing

*Fetal hemoglobin*Liver and renal function chemistries

*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.

CLASSIFICATIONDesignationDesignationCriteriaCriteria

Peripheral bloodBM biopsy

Severe aplastic anemia

-2 / 3 values-Neutrophils > 500/L

-Platelets > 20,000/ ul--Reticulocyte index >

1%

-Marked hypocellular > 25% cellularity

-Moderate hypocellular >25-50%

-normal cellularity with >30% of remaining cell hematopoietic

Very severe aplastic anemia

As above but neutrophils > 200/LInfection present

Treatment Options

Bone Marrow Transplant

GrowthHormones

Immune SuppressiveTherapy

Supportive Care

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TREATMENT1-Withdrawal of the etiologic agent

2-Supportive treatmentBlood 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.

AANewer

*Mycophenolate mofetil (MMF) - cytotoxic to T cells

*Monoclonal Ab against IL-2 receptor which is present on activated lymphocytes

AA - Outcomes

Age, Younger is betterBMT

<20 yr with a sib… 75%20 - 40 yr with a sib…60%

<20 yr unrelated BMT… 40%20 - 40 yr unrelated BMT…35%

Immunosuppression - 60 - 80%But for how long and consequences…

Fanconi AnemiaFanconi AnemiaFanconi AnemiaFanconi Anemia

History: Guido FanconiFanconi 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)

Fanconi Anemia (FA)Rare (< 1/ 100,000 births)Autosomal recessiveMany physical featuresBut up to 20-25% will have no physical findings

Mean age at dx 7.8 yrs

Autosomal Recessive Autosomal Recessive InheritanceInheritance

FA- Clinical

Abnormality %of FA Patients

Skin60%

Short Stature57%

Upper Limb Abnl48%

Head/ Microcephaly27%

Renal23%

Dev. Delay13%

None Reported20%

Short Stature Only1%

Skin Only3%

Progressive bone marrow failure Most common etiology of inherited bone marrow failureOthers 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)

Clinical Features

Clinical FeaturesIncreased 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

FA - geneticsIdentification of subtypes (compliment groups)A, B, C, D1, D2, E, F, GIdentical clinicallySub-units of a common protein/ common pathway

Protein modifies FANCD2FANCD2 interacts with BRCA1 and 2BRCA1 and 2 needed for DNA repair

PATHOPHYSIOLOGYDNA 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.

*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 ionizingradiation.

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

DiagnosisBased on chromosomal hypersensitivity to cross-linking agentsChromosome fragility test: Mitomycin C (MMC) or diepoxybutane (DEB) added to lymphoctyes – increases the number of chromosome breaks and radial structuresVery specific for FA, regardless of severity of diseaseCan do chromosome breakage analysis on amniotic cells, chorionic villus cells or fetal blood

FA cells were treated with mitomycin C and harvested in metaphase. Typical abnormalities include radial formation (green circle) and chromosome breaks (red arrows).

Initial managementRefer for genetic counselingTesting of siblingsRenal ultrasound, hearing test, eye examEndocrine evaluation if evidence of growth failure (check growth hormone levels, TSH)Referral to hand surgeon for radial ray defects Bone marrow biopsy

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

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)

Other Congenital Marrow Failures

Dystkeratosis CongenitaRareDifferent modes of inheritanceEctodermal dysplasia

50% develop aplastic anemia in midteens

Schwachman-DiamondCartilage-Hair HypoplasiaFamilial Marrow Dysfunction

Marrow Failure

Pearson’s syndromeSeckel’s syndromeAmegakaryocytic ThrombocytopeniaNoonan’s syndrome

Marrow FailureSingle Cytopenias

-Pure Red Cell Aplasia (Diamond-Backfan)

-Congenital Neutropenia (Kostmann’s) -Thrombocytopenia with Absent

Radii

Definition

A syndrome characterized by

Normocytic normochromic anemia

Reticulocytopenia <1%

BM erythroblasts < 0.5%

Aplasia selective to erythroid cell line

only!

EpidemiologyRelatively uncommonMay affect any age group but predominantly ofinfancy and childhood

M=F

No ethnic predisposition

Of autosomal dominant inheritance

Etiology & Pathogenesis

Congenital hypoplastic

anemia

)Diamond-Blackfan syndrome(

Acquired PRCA

Primary

Secondary

PrimaryPrimaryAutoimmunePreleukemicIdiopathic

SecondarySecondaryThymoma

Hematologic malignanciesSolid tumors

InfectionsChronic hemolytic anemiasCollagen vascular diseases

PregnancySevere renal failure

Severe nutritional deficienciesDrugs & chemicals

Miscellaneous

Acquired PRCA

Mechanisms of Immunologic Inhibition

Antibodies directed againstErythropoietin

Erythroblasts?

Cellular inhibitionInhibitory T cellsNK cells

Pure red cell aplasia

IgG inhibitors T cell inhibition Parvovirus

Erythropoietin Epo Responsive cells

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

Laboratory Evaluation

Diagnostic criteria:

--Normochromic, usually macrocytic anemia, relative to patient’s 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

BM*Absence of erythroblasts <1% 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

TreatmentCongenital Hypoplastic

Anemia

Corticosteroids

AlloBMT

IL-3 –experimental

Patients refractory to all treatments – regular transfusions & desferioxamine

Treatment Acquired PRCA

-Discontinuation of all drugs-R/O infections

-If parvovirus suspected – high dose IgG-In the presence of thymoma – thymectomy

-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

Treatment Acquired PRCA

For primary or secondary PRCA not responding to treatment of underlying

disease:PrednisoneCyclophosphamide / azathioprineCyclosporineATGHigh dose IgGPlasmapheresisSplenectomyRituximab

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