2. ST
Pt is a 43 year old woman who was in her usual
state of health until 03/16/11 when she presented
to outside ER with left flank pain and dark urine
for two days.
Found to have hct of 26 with platelet count of
26k.
No hemolysis on labs.
Peripheral smear reveals no atypical cells with few
large platelets. Initially thought to have ITP-
given IVIG x 1. Did not response to IVIG.
Required daily platelet transfusions.
3. Bone marrow biopsy
markedly hypocellular
marrow with 80% fat.
Cellularity is composed of
entirely maturing erythroid
elements. Myeloid elements
are markedly decreased.
Occasional segmented
forms noted.
Megakaryocytes rare.
Stainable iron increased.
No ringed sideroblasts.
Reticulin focally increased.
No features of parvovirus
seen. Several blast forms
seen.
4. Diagnosis of Aplastic Anemia
Marrow is profoundly hypocellular
with decrease in all elements.
Residual hematopoietic cells are
morphologically normal.
Malignant infiltrates and fibrosis is
absent.
Hematopoiesis is non-megaloblastic.
5. Severity
Moderate aplastic anemia
Marrow cellularity <30%
Absence of severe pancytopenia
Depression of at least two of three blood elements below
normal.
Severe
o Bone marrow cellularity <25% or marrow showing <50% normal
with two of three peripheral blood count criteria:
o ANC <500
Plt <20k
Retic count <40k
Very Severe
All of above plus ANC less than 200.
11. Epidemiology
International Aplastic Anemia and
Agranulocytosis Study (IAAAS)
found 2 confirmed cases per one
million people (two PNH units)
Thailand- 4 cases per million
13. Etiology and Pathogenesis
Genetic predisposition found in HLA-
DR2.
This correlates to response to
immunosuppressants.
Similar results found in hypoplastic
MDS.
14. Pathogenesis
Immune-mediated T-cell destruction
of marrow
Young demonstrated that removal of
lymphocytes from aplastic bone
marrow improved colony number in
tissue culture and addition of
lymphocytes to normal marrow
inhibited hematopoiesis in vitro.
15.
16.
17. Telomere shortening
Originally thought to be due to stem-cell exhaustion.
Telomere shortening also found in X-linked form of
dyskeratosis congenita due to mutations in DKCI.
Telomere shortening also found in mutations in TERC
found in AD patients with constitutional
Subsequent analysis of patients with acquired aplastic
anemia found mutations in TERC and TERT.
Interestingly, family members of patients who share
these mutations can have normal blood counts but
hypocellular marrows, reduced CD34 counts and poor
hematopoietic colony formations and short telomeres.
Therefore, 1/3 to ½ of patients with aplastic anemia
have short telomeres but mutations are only found in
10% of patients.
19. Treatment
ATG:
Lymphocyte numbers decreased within the
first few days of therapy and then return to
pretreatment levels within a week or so.
Appears to be immunomodulatory as well as
lymphocytotoxic- producing a state of
tolerance by preferential depletion of activated
T cells.
Rabbit appears to be more potent that the
horse formulation.
Cyclosporine:
its selective effects on T-cell function is due to
direct inhibition on the expression of nuclear
regulatory proteins, resulting in decreased T-cell
proliferation and activation.
20. Clinical Endpoints
Response defined as transfusion
independence.
About 50% response rate with horse
ATG.
Relapse defined as requirement of
additional immunosuppresants.
Happens in 30-40% of patients.
Clonal evolution occurs in 15% of
cases.
Into MDS, AML, PNH
21. Improving on ATG & cyclosporine
for first line management of AA?
Addition of high dose steroids did not improve
outcomes and just added to toxicity.
Addition of G-CSF and GM-CSF did not improve
outcomes
Addition of mycophenolate did not improve
response rates or outcomes.
Sirolimus was equally ineffective.
Cyclophosphamide was associated with a higher
death rate due to prolonged neutropenia.
22. Relapsed/Refractory
Aplastic Anemia
Rabbit ATG- if patient has not seen
it before and had a decent response
to initial treatment.
Alemtuzumab has been shown in
the relapsed setting to be effective.
Cyclophosphamide has a 50%
response rate in relapsed setting.
23. Moderate Aplastic Anemia
Role for duclizumab, humanized
monoclonal antibody to IL-2
receptor
Role for androgen therapy
24. HSCT
Definitive therapy for several malignant
and non malignant disorders
-autologous : stem cells harvested from
the patient
-allogeneic : stem cells collected from a
donor
25. ALLOGENEIC HSCT
Ideal donor is a HLA-identical sibling
Even minor histocompatibility loci
variations can cause graft rejection/graft
versus host disease
ABO blood group compatibility not
essential
If HSCT is successful,blood group of
recipient changes to that of donor
26. - myeloablative -> high doses
chemotherapy administered to
eradicate malignant cells,to clear
space for growth of donor stem
cells,to suppress host immune
response
- non myeloablative -> donor T cells
are used to eradicate both
malignant and non malignant cells
of host origin
27. Harvesting :
-Under GA/spinal.
-Repeated aspiration done.
-From posterior iliac crests.
-Minimum no.of marrow cells required is 1-3 X
10 power 8 cells/kg of recipient’s body
weight.
28. Engraftment :
-These donor marrow cells are
transfused through peripheral veins.
-Enter into host marrow space and
start engrafting.
-2-3 weeks for engraftment to occur.
29. -Prone to bacterial and fungal infections.
-Protective isolation required during this period.
-Require multiple red cell and platelet
transfusions for the thrombocytopenia.
-Engraftment considered successful when
peripheral ANC > 500/mm3 on three
successive days.
Risk of GVHD after transplant -> irradiation
prior to transplant to inactivate donor
lymphocytes
30. GRAFT VERSUS HOST DISEASE
Occurs in allogeneic stem cell
transplant.
Acute / chronic .
Acute :
Occurs within the first 3 months after
transplant
Classically affects only skin,gut and
liver
(skin lesions,diarrhoea,jaundice)
Accompanied by fever
31. Chronic :
Develops later than 100 days after the
transplant.
De novo / follows acute GVHD .
Limited/extensive .
Resembles scleroderma( skin rash,sicca
complex,sclerosing bronchiolitis,hepatic
dysfunction ).
Mortality of 20-40% .
Mx – immunosuppressive agents.