Benzene Chlorinated hydrocarbons Organophosphates

36 Aplastic Anemia: Acquired and Inherited Flashcards by Amelie Avenido

The diagnosis of Aplastic Anemia usually requires the presence of pancytopenia defined as:

Neutrophil count:
Platelet count:
Hemoglobin:
Absolute Reticulocyte count:

accompanied by a hypocellular marrow without abnormal or malignant cells or fibrosis

Neutrophil count: fewer than 1.5 × 109/L
Platelet count: fewer than 50 × 109/L
Hemoglobin: less than 100 g/L
Absolute Reticulocyte count: fewer than 40 × 109/L

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Degree of Severity of Acquired Aplastic Anemia

Moderately severe:
Severe:
Very severe:

Moderately severe: Hgb <100 g/L ARC <40.0 × 109/L NC <1.5 × 109/L PC <50.0 × 109/L

Severe: Hgb <90 g/L ARC <30.0 × 109/L NC <0.5 × 109/L PC <30.0 × 109/L

Very severe: Hgb <80 g/L ARC <20.0 × 109/L NC <0.2 × 109/L PC <20.0 × 109/L

Moderately severe: At the time of diagnosis at least 2 of 3 blood counts should meet these criteria

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The highest frequency of aplastic anemia occurs in persons between the ages of_______years; a second peak occurs between the ages of ________years.

15 and 25 years

65 and 69 years

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The male-to-female incidence ratio of aplastic anemia in most studies is approximately

One

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Toxins that cause AA

Benzene
Chlorinated hydrocarbons
Organophosphates

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Viruses that cause AA

Epstein-Barr virus
Non-A, -B, -C, -D, -E, or -G hepatitis virus
HIV

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Inherited Causes of AA

Fanconi anemia
Dyskeratosis congenita
Shwachman-Diamond syndrome
Other rare syndromes

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The final common pathway to the clinical disease is

A decrease in blood cell formation in the marrow

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Reduced hematopoiesis in most cases of aplastic anemia results from

Cytotoxic T-cell–mediated immune suppression of very early CD34+ hematopoietic multipotential progenitor or stem cells

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A relationship between acquired aplastic anemia and hereditary aplastic anemia (FA or dyskeratosis congenita) has been suggested because of the defects in _______________________

Telomerase and telomere repair

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The most notorious drug documented to cause aplastic anemia

Chloramphenicol

The occurrence of aplastic anemia appears to be idiosyncratic, perhaps related to an inherited sensitivity to the nitroso-containing toxic intermediates.

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Anti-malarial with evidence that it cause AA

Quinacrine (Atabrine)

The aplasia occurred during administration of the offending agent and was preceded by a characteristic rash in nearly half the cases

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Causes AA because there is delayed oxidation and clearance of a related compound, acetanilide

Phenylbutazone

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A histamine H2-receptor antagonist, is occasionally implicated in the onset of cytopenias and aplastic anemia, perhaps owing to a direct effect on early hematopoietic progenitor cells

Cimetidine

There is drug interactions or synergy with: carmustine and chloramphenicol

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Drugs Associated with Aplastic Anemia - High Risk

Antineoplastic drugs:
Alkylating agent
Antimetabolite
Cytotoxic antibiotic

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Was the first chemical linked to aplastic anemia, based on studies in factory workers before the 20th century

Benzene

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An uncommon connective tissue disorder with painful swelling and induration of the skin and subcutaneous tissue, has been associated with aplastic anemia

Has been largely unresponsive to therapy

Eosinophilic fasciitis

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Total-body exposure to radiation between _______Gy leads to gastrointestinal symptoms and depression of leukocyte counts, but most patients recover.

1 and 2.5 Gy

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Although unusual, severe marrow aplasia can follow use of the alkylating agent,________, and may persist indefinitely.

Busulfan

Marrow aplasia may develop in patients 2–5 years after discontinuation of alkylating agent therapy.

These cases often evolve into hypoplastic myelodysplastic syndromes.

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A rare exception to the negligible pathogenetic role of hematopoietic growth factors in the etiology of aplastic anemia is the homozygous or mixed heterozygous mutation of the TPO receptor gene, MPL, which can cause

Amegakaryocytic thrombocytopenia

Evolves later into aplastic anemia

Eltrombopag, a TPO receptor agonist, can stimulate mono- or, in some patients, bilineage or trilineage recovery of blood counts that may be sustained off therapy

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TRUE OR FALSE

Lymphadenopathy and splenomegaly are not features of aplastic anemia; such findings suggest an alternative diagnosis such as a clonal myeloid or lymphoid disease.

TRUE

Lymphadenopathy and splenomegaly are not features of aplastic anemia; such findings suggest an alternative diagnosis such as a clonal myeloid or lymphoid disease.

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TRUE OR FALSE

Significant qualitative changes of red cell, leukocyte, or platelet morphology on the blood film are features of classical acquired aplastic anemia.

FALSE

Significant qualitative changes of red cell, leukocyte, or platelet morphology on the blood film are not features of classical acquired aplastic anemia.

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TRUE OR FALSE

The plasma contains high levels of hematopoietic growth factors, including EPO, TPO, and myeloid colony-stimulating factors.

TRUE

The plasma contains high levels of hematopoietic growth factors, including EPO, TPO, and myeloid colony-stimulating factors.

Other findings:
* Macrocytes may be present in the blood film and the mean cell volume increased.
* Platelets function normally.
* Occasionally only one cell line is depressed initially

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TRUE OR FALSE

Plasma iron values are usually high, and Fe clearance is prolonged, with decreased incorporation into red cells.

TRUE

Plasma iron values are usually high, and Fe clearance is prolonged, with decreased incorporation into red cells.

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Marrow Findings in Aplastic anemia

Numerous spicules with empty, fat-filled spaces, and relatively few hematopoietic cells

Refers to spicules that are cellular or even hypercellular

“hot spots” ## Footnote These focal areas of residual hematopoiesis *do not appear to be of prognostic significance.*

Cytogenetic analysis in aplastic anemia is

Normal ## Footnote **Clonal cytogenetic abnormalities** in otherwise apparent aplastic anemia is indicative of an underlying **hypoplastic clonal myeloid disease.**

Imaging that can be used to **distinguish between marrow fat and hematopoietic cells**

Magnetic resonance imaging ## Footnote Magnetic resonance imaging studies of bone may be useful in differentiating severe aplastic anemia from clonal myeloid syndromes. The former gives a fatty signal and the latter a diffuse cellular pattern.

A reticulocyte percentage of less than ______% is strongly indicative of aplastic erythropoiesis and, when coupled with leukopenia and thrombocytopenia, points to aplastic anemia.

0.5%

As many as_____ of patients with otherwise typical aplastic anemia have evidence of **glycosylphosphatidylinositol molecule defects and diminished phosphatidylinositol-anchored protein** on leukocytes and red cells as judged by flow cytometry, analogous to that seen in PNH.

50%

As many as____% of patients with aplastic anemia have a five-year probability of myelodysplasia developing.

20%

Mutations that are increased in prevelance with patient age

ASXL1 and DNMT3A

Mutations that were of similar frequency in all age groups

BCOR, BCORL1, and PIGA

Three principal options: for treatment in AA

(1) syngeneic or allogeneic hematopoietic cell transplantation (2) combination immunosuppressive therapy with ATG and cyclosporine, and (3) eltrombopag

# TRUE OR FALSE In general, transplantation is the preferred treatment for children and most otherwise healthy younger adults.

TRUE In general, **transplantation** is the preferred treatment for children and most otherwise healthy younger adults.

The preferred stem cell source

A histocompatible sibling matched at the HLA-A, -B, -C, and -DR loci ## Footnote An allele-level HLA-matched unrelated donor can be used in younger patients

# TRUE OR FALSE Red cell and platelet transfusions be used sparingly in potential transplant recipients to minimize sensitization to histocompatibility antigen

TRUE Red cell and platelet transfusions be used sparingly in potential transplant recipients to minimize sensitization to histocompatibility antigen

Packed red cells to alleviate symptoms of anemia usually are indicated at hemoglobin values:

Below 80 g/L

# TRUE OR FALSE It is important to transfuse patients with red cells (or platelets) from family members if transplantation within the family is possible

FALSE It is important **not to transfuse** patients with red cells (or platelets) **from family members** if transplantation within the family is remotely possible ## Footnote Because this approach may **sensitize patients to minor histocompatibility antigens**, increasing the risk of graft rejection after hematopoietic cell transplantation.

Preferred platelet unit for previously pregnant or transfused patients who are already **allosensitized** or who become so after treatment with leukoreduced platelets

Single-donor HLA-matched apheresis-harvested platelets

The major curative approach in AA

Hematopoietic Cell Transplantation ## Footnote The results of transplantation are best in patients **younger than age 20 years (80%–90% long-term survival)** but decrease every decade of increasing age thereafter. Optimal with **HLA-matched sibling** transplantation.

# TRUE OR FALSE Marrow stem cells perform better than blood stem cells when used as a source for patients with aplastic anemia, although this is under continued study.

TRUE **Marrow stem cells** perform **better** than blood stem cells when used as a source for patients with aplastic anemia, although this is under continued study.

In patients older than age 40 years, survival in matched-sibling transplant is reduced to approximately________%.

50%

Regimen that appear to improve outcome by **decreasing the frequency of chronic graft-versus-host disease**, which could make it useful in treating **older** patients.

Alemtuzumab-containing regimens

If there is an HLA mismatch at one or more loci, especially _____or ____, the outcome is compromised,and immunosuppression with combined therapy may be preferred initially

HLA-A or -DRB1

Act principally by **reducing cytotoxic T cells** **Release hematopoietic growth factors** from T cells

Antilymphocyte and Antithymocyte Globulin

# TRUE OR FALSE Rabit ATG is superior to equine and, if available, is recommended as the first line of therapy

FALSE **Equine** ATG is superior to rabbit and, if available, is recommended as the first line of therapy

# TRUE OR FALSE ATG treatment may accelerate platelet destruction, reduce the absolute neutrophil count, and cause a positive direct antiglobulin (Coombs’) test.

TRUE ATG treatment may accelerate **platelet destruction, reduce the absolute neutrophil count**, and cause a **positive direct antiglobulin (Coombs’) test**.

Characterized by spiking fevers, skin rashes, and arthralgia, commonly occurs **7–10 days** from the first dose

Serum sickness

Management of Serum sickness

* Glucocorticoid (eg, prednisone 1 mg/kg) from day one of ATG treatment and for two weeks thereafter * Fever, rigors, rash, hypotention, and hypoxia can be minimized by administration of acetaminophen and diphenhydramine before each dose of ATG. * Supplementation with intravenous hydration for hypotension and oxygen administration for hypoxia. * In cases of severe reactions, the administration of ATG can be slowed or temporarily discontinued until improvement occurs, and then reinstituted at a slower rate of infusion if necessary.

Approximately _______of patients no longer require transfusion support after treatment with ATG alone.

One-third

A cyclic polypeptide that **inhibits IL-2 production** by T lymphocytes and prevents expansion of cytotoxic T cells in response to IL-2

Cyclosporine

Initial dose of Cyclosporine

**10–12 mg/kg per day **for at least** 6 months** and with downward dose modification after six months for as long as **12 months**. ## Footnote Responses usually are seen by **three months** and may range from achieving transfusion independence to complete remission

Trough blood levels of Cyclosporine

200–400 ng/mL

A **TPO receptor agonist** used to stimulate platelet production in patients with immune thrombocytopenia May **expand stem cell numbers** and **promote DNA repair**

Eltrombopag ## Footnote **Multilineage hematopoietic response** occurred, leading to restoration of granulopoiesis, erythropoiesis, and megakaryocytopoiesis with a subsequent increase in neutrophil, erythrocyte, and platelet counts, sometimes to normal levels **MPL receptors** are present on hematopoietic stem cells A **higher dose of eltrombopag (150 mg/day)** and **longer treatment (at least 24 weeks)** increases the likelihood of response

Combination Immunotherapy

* ATG (40 mg/kg per day) for 4 day * Cyclosporine (6 mg/kg per day in divided doses every 12 hours) for 6 months * Methylprednisolone (1 mg/kg per day) for 2 weeks * Eltrombopag is given at 150 mg from day 1 for 6 months

# TRUE OR FALSE G-CSF added to the combined immunosuppressive therapy does not increase response rate or survival.

TRUE G-CSF added to the combined immunosuppressive therapy does not increase response rate or survival.

A monoclonal **anti-CD52** antibody that targets that antigen on T lymphocytes, has been an effective immunosuppressive agent in both **relapsed and refractory patients**

Alemtuzumab

An alternative thrombopoietin receptor agonist that is a **larger** molecule than eltrombopag and requires **parenteral** administration It binds to the thrombopoietin receptor site, **cMPL**

Romiplostim

Alemtuzumab produces profound and persistent___________.

Lymphopenia

Stimulate the **production of EPO**, and their metabolites stimulate erythropoiesis when added to marrow cultures in vitro. May be useful in the treatment of aplastic anemia syndromes resulting from **shortened telomeres**.

Androgens

Therapy with myeloid growth factors is probably best reserved for

Episodes of severe infection As a preventive measure before dental work or other procedures that would compromise mucosal barriers in patients who have not responded to hematopoietic cell transplant or immunotherapy ## Footnote * Generally, prophylactic use of growth factors is not warranted.

# TRUE OR FALSE Prophylactic use of growth factors is warranted.

FALSE Prophylactic use of growth factors is not warranted.

The most important prognostic feature

Absolute neutrophil count

Hematopoietic cell transplantation is curative for approximately: Patients younger than 20 years of age: Between the ages of 20 and 40 years: Older than age 40 years:

Patients younger than 20 years of age: 80%–90% Between the ages of 20 and 40 years: 70% Older than age 40 years 50%

The best outcomes occur in patients who have:

* Allele-based HLA-matched sibling * Have not been exposed to immunosuppressive therapy before transplantation * Have not been exposed and sensitized to blood cell products * Have had a marrow rather than a blood stem cell donor product, and * Have not been subjected to high-dose radiation in the conditioning regimen for transplantation

Predictive of a better response to therapy

* Higher initial absolute reticulocyte and lymphocyte counts * High proportion of Treg B cells

AD Rare Inherited Syndromes Associated with Aplastic Anemia

* Ataxia-pancytopenia (myelocerebellar disorder) * WT syndrome ## Footnote The rest autosomal recessive

The most common form of constitutional aplastic anemia The great majority of patients have mutations of FANCA, FANCC, or FANCG

Fanconi anemia (FA)

First step in understanding the genetic basis of FA

Diepoxybutane test ## Footnote In this test, diepoxybutane results in **chromosome fragmentation** in the cells of patients with FA.

Hereditary cause of AA: pancreatic insufficiency, steatorrhea

Schwaman Diamond Syndrome

Approximately 5% of patients with FA exhibit the _____________ phenotype

VACTERL with hydrocephalus (VACTERL-H) ## Footnote This requires having **3 of 8** features, including vertebral anomalies, anal atresia, congenital heart disease, tracheoesophageal fistula, esophageal atresia, renal abnormalities, limb abnormalities, and hydrocephalus

Hereditary cause of AA: nail dystrophy, mucosal leukoplakia A predisposition to malignant transformation The disease is a reflection of **telomere complex dysfunction** and results from defective telomerase activity resulting from mutations in the telomerase-related genes

Dyskeratosis congenita

Responsible for the X-linked recessive form of Dyskeratosis congenita

DKC1 gene ## Footnote DKC1 encodes **dyskerin**, which is a conserved multifunctional protein component of the telomerase complex

Homozygous recessive mutations in the **TERT** gene produce a severe variant of dyskeratosis, referred to as the

Hoyeraal-Hreidarsson syndrome

Used to confirm Dyskeratosis congenita

Genetic analysis for telomerase complex gene mutations

# TRUE OR FALSE In Dyskeratosis congenita, transplantation might improve the cytopenias, but not the abnormalities of other organs or the frequency of secondary nonhematopoietic cancer.

TRUE In Dyskeratosis congenita, **transplantation might improve the cytopenias, but not the abnormalities of other organs** or the frequency of secondary nonhematopoietic cancer. ## Footnote The incidence of **squamous cell carcinoma** of mucosal sites is increased, and the squamous cell carcinoma often originates in sites of leukoplakia in the skin, gastrointestinal, or genitourinary tracts.

Manifests as exocrine pancreatic insufficiency with secondary steatorrhea, blood cell deficiencies, and skeletal abnormalities Results from mutations in the **SBDS gene on chromosome 7q11**, which induces accelerated cellular apoptosis via the FAS pathway

Shwachman-Diamond syndrome

# Shwachman-Diamond syndrome Pancreatic insufficiency can be established by

Low serum trypsinogen ## Footnote in patients younger than 3 years of age

Cytogenetic abnormalities involving chromosomes _________ have been described in marrow cells of patients with Shwachman-Diamond syndrome

Chromosomes 7 and 20 ## Footnote Have a significant risk of progression to a myelodysplastic syndrome or AML

Results from mutations in the TPO receptor gene, **MPL**

Congenital (hereditary) amegakaryocytic thrombocytopenia (CAMT) ## Footnote * **CAMT I** with mutations leading to **complete loss-of-function of the TPO receptor**, resulting in more severe thrombocytopenia and a rapid progression to pancytopenia (aplastic anemia) * **CAMT II**, resulting from a variety of missense mutations, in which affected children have an increase in platelet count above 50 × 109/L with time and much slower progression to and sometimes less severe pancytopenia

Hereditary cause of AA: cafe au lait spots, VACTERL phenotype

Fanconi anemia

Hereditary cause of AA: bilateral sensorineural deafness, agranulocytosis, SCID Results from a pluripotential stem cell defect as both lymphoid and granulocytic progenitors are affected.

Reticular dysgenesis

Results from mutations in the **ATR** gene, and marrow cells exhibit **heightened sister chromatid exchange**

Seckel syndrome

# TRUE OR FALSE Inherited aplastic anemias can be treated by hematopoietic cell transplantation but, if successful, this step does not correct somatic abnormalities, only the hematopoietic and immunologic defect.

TRUE Inherited aplastic anemias can be treated by **hematopoietic cell transplantation** but, if successful, this step **does not correct somatic abnormalities**, **only the hematopoietic and immunologic defect**.

36 Aplastic Anemia: Acquired and Inherited Flashcards

(85 cards)