Rolla Abu-Arja, clinical director of pediatric bone marrow transplant in Nationwide Children's Hospital (Columbus, OH) discusses iron overload in hematopoetic cell transplantation.

1. R O L L A A B U - A R J A , M D
P E D I A T R I C H E M A T O L O G Y C O N F E R E N C E
Iron Overload in Hematopoietic
cell Transplantation

2. Iron
 4.5% of earth crust
 Constitute 0.005% of body weight in humans
 Total body iron content
Newborn infant 300 mg
Adult female 2.5 gm
Adult male 3.5 gm

3. Too much iron is bad
Generate free radicals
Causes oxidant injury to cells
Too little iron is bad
Anemia
Non-hematologic effects of iron
depletion
Protective mechanisms
 Iron absorption highly
regulated and
minimized
 Iron in cells and plasma
is tightly bound to
proteins ( transferrin,
ferritin, hemoglobin etc.
Preventive mechanisms
 Iron absorption efficient
and tightly regulated
 Iron loss is minimized
Iron

4. Distribution of Iron
hemoglobin
ferritin and hemosiderin
22%
myoglobin 10%
cytochromes transferrin
catalase etc 3%
Hemoglobin 65%
Ferritin and
Hemosiderin
22%
Myoglobin
10%

5. Iron Absorption
 Depends on:
Iron content in diet
bioavailibility of dietary iron
receptors on mucosal cells
• Heme iron> non-heme iron
• Ferrous ( Fe+2) > Ferric (Fe+3)

6. Systemic and cellular iron balance is very tightly
regulated
 Around 1-2 mg of iron is absorbed from diet
everyday
 Iron circulates in plasma bound to transferrin ( no
free iron)
 60-70% of iron is incorporated into Hb in RBC and
the rest is stored in hepatocytes, myoglobin and RES
macrophages
 1–2 mg of iron is lost daily from the skin and the
intestine and, in women, through menstruation

7. Absorption of Iron by the Enterocyte
Ferrireductase
Fe+3
Fe+2 DMT1
Heme
Iron
Mucosal Surface
Basolateral surface

8. Absorption of Iron by the Enterocyte
Mucosal Surface
Basolateral surface
Ferritin
Ferroportoin
Fe+3
Fe+2 Heme IronDMT1
Ferrireductase
Hepcidin
Fe+2
Hephaestin (Copper-containing)
Fe+3
Fe+3
Transferrin in Plasma
Sloughing of entercyte
And its remaining
iron

9. Iron metabolism
 Transferrin binds iron in blood
-free iron usually not present
-saturated in iron overload
 Ferritin surrounds iron in storage
- elevated in iron overload
 Normal 20 to 300 g/L
 Rises to > 1,000 and up for iron overload
 Ferritin-iron complex aggregates and degraded
into insoluble hemosiderins (hemosiderosis)

10. Iron can not be excreted
 Humans do not have any physiological mechanisms
to excrete excess iron
 In conditions of iron excess, hepcidin levels increase
and inhibit intestinal absorption and release of
storage iron

11. Iron toxicity
Iron mediate the conversion of
hydrogen peroxide highly toxic free radicals
Leads to tissue damage by:
 Oxidation of proteins
 Peroxidation of membrane lipids
 Modification of nucleic acids
Tissue damage is clinically most evident in the heart
and the liver.

12.  Cardiac failure
 Liver cirrhosis/fibrosis/cancer
 Diabetes mellitus
 Infertility
 Arthritis
Possible Complications of
Iron Overload
Andrews NC. N Engl J Med. 1999;341:1986-1995.

13. Iron and infections
 Iron is an essential cofactor for the growth of a
number of opportunistic bacteria and fungi
 Free iron can also increase susceptibility to
infections by inhibition of chemotaxis and
phagocytosis and impairment of cellular immunity
Bone Marrow Transplantation (2008) 41, 997–
1003; doi:10.1038/bmt.2008.99 N S Majhai
H M Lazarus and L J Burns

14. Iron overload in transfusion-dependent anemias
 RBC transfusions
 Ineffective erythropoiesis and hemolysis (by stimulating
the body's regulatory mechanisms to inadvertently
increase intestinal absorption of iron.)
 Tissue iron accumulation leads to progressive
dysfunction of the heart, liver and endocrine glands.
 Tissue iron deposition can begin within 1–2 years, but
clinically evident cardiac or hepatic dysfunction may not
occur till 10 or more years from initiation of transfusion
therapy.
 End-organ damage can occur earlier in patients with
other risk factors

15. Transfusion associated anemias guidelines
 Estimation of LIC by liver biopsy or imaging is
recommended after 1 year of regular transfusions to
determine the need for iron-chelation therapy.
 Iron chelation is initiated once LIC rises above 3 mg
per gm dry weight and is used to maintain levels
between 3-7 mg/gm.

16. Body iron burdens
LIC
 > 15 mg per gm liver, dry weight, are at an increased
risk of cardiac disease and early death
 7–15 mg per gm high risk for hepatic fibrosis and
endocrine complications
 3–7 mg per gm: organ damage typically does not
occur (similar to those seen in heterozygotes for
hereditary hemochromatosis
 The risk of cardiac disease and early death is
increased in patients with serum ferritin of more
than 2500 ng/ml

17. Assessment of body iron stores
 Liver biopsy with estimation of liver
iron concentration LIC is considered to
be the reference method for measuring
hepatic iron stores.

18. Superconducting QUantum Interference
Device
-High-power magnetic field
-Iron interferes with the field
-Changes in the field are
detected
Noninvasive, sensitive, and
accurate
Limited availability
Superconductor requires high
maintenance
Only 4 machines worldwide

19. MRI
Clark PR, et al. Magn Reson Med. 2003;49:572-
575.
An R2 image of an iron-overloaded human liver superimposed on a T-2 weighted image.
Bright areas represent high iron concentration; dark areas represent low iron
concentration

20. Assessment of body iron stores
Test Advantages Disadvantages
Liver Biopsy Reference method
Can assess the degree of
fibrosis and can evaluate
other causes of hepatic
dysfuction
Invasive procedure, not
feasible in patients with
coagulopathy or
thrombocytopenia
Superconducting
susceptometry (SQUID)
Good correlation with
liver biopsy/non invasive
Very limited availability
MRI of the liver Good correlation with
liver biopsy/non invasive
( T2 or R2 MRI)
Variety of MRI
techniques have not been
validated with liver bx
CT of the liver Non invasive and
available
Variable correlation with
liver bx
Serum ferritin and
transferrin saturation
Non invasive and
available
Sensitive but not specific
for iron overload and
Poor correlation with
liver bx

21. Iron overload in HCT
 Due to RBC transfusions, both during the initial
treatment of their disease and in the post transplant
period
 Carrier state for hereditary hemochromatosis, can
amplify this risk
 Other mechanisms :
Inhibition of erythropoiesis
Release of iron from the bone marrow and liver due
to cell damage from conditioning regimen toxicity

22. Iron overload and HCT
Altes et al
 Reviewed liver samples obtained on autopsy in 59
recipients of auto and allo HCT.
 The median LIC was 7.7 mg /gm DW
 40 % of patients had an LIC of >5.6 mg / gram
Rose et al cross sectional study ( 9 year follow up)
 38/65 (58%) patients had above normal ferritin.
 Increased LIC 6.5 mg/gm DW was seen in 31/32 patients
with elevated ferritin who underwent a T2* MRI of the
liver
Altes A, Remacha AF, Sarda P, Sancho FJ, Sureda A, Martino R et al Bone
Marrow Transplant 2004; 34: 505–509
Rose C, Ernst O, Hecquet B, Maboudou P, Renom P, Noel MP et al). Haematologica 2007; 92:
850–853.

23. Majhail et al
 Cross sectional study 19/56 allo HCT survivors
(median followup 2.5 years) had ferritin
>1000 ng/ml
 Of these, 18 (32%) had elevated LIC (median
7 mg/gm, DW on R2 MRI of the liver
 LIC>5 mg per gram DW was present in 13 (23%)
patients.

24. The patients with ferritin level more than
1000 ng/ml before HSCT (F>1000)
showed lower OS and EFS, and higher
TRM rate than those with ferritin level less
than 1000 ng/ml with (IC) or without
(F<1000) iron-chelating therapy.
Bone Marrow Transplantation (2009) 44, 793–797;
doi:10.1038/bmt.2009.88; Effect of iron overload and
iron-chelating therapy on allogeneic hematopoietic SCT in
children

25. Iron overload and transplant complications
Early (<1 year) Post
transplant
 Infections
 Acute GVHD
 VOD
 Non relapse mortality
Late (>1 year) post
transplant
 Infections
 Chronic GVHD
 Liver function
abnormalities
 Cardiac late effects
 Non relapse mortality

26. No studies that describe the role of iron overload
in late-onset cardiomyopathy and hepatic
fibrosis and cirrhosis in patients transplanted for
diseases other than thalassemia.
In children with thalassemia who have
undergone an allo HCT, post transplant iron-
chelation has been shown to reverse hepatic
fibrosis and cardiomyopathy.

27. Treatment of iron overload after HCT
Take into consideration:
 The need for ongoing RBC transfusion therapy
 Time since transplantation
 Ability to tolerate iron-chelating therapy
 Urgency to reduce body iron stores.

28. Treatment options for iron overload after HCT
Modality Advantages Disadvantages
Phlebotomy Extensive experience and
proven efficacy
No side effects
Not feasible in patients
with anemia and poor
venous access
Deferoxamine Extensive experience with
proven efficacy
Inconvenient
administration route
Side effects ( ototoxicity,
renal etc.)
Deferiprone Oral iron chelator Unproven efficacy
Side effects
Deferasirol Oral iron chelator
Efficacy similar to
deferoxamine
Long term safety profile
not established
Side effects..

29. Phlebotomy
 Phlebotomy program is recommended to patients with a
ferritin value > 1000 ng/mL and IO confirmed by SQUID
(LIC >7mgFe/g Dw).
 With each phlebotomy, approximately 350-500 mL of
whole blood is removed
 CBC is analyzed before each phlebotomy, and the
procedure should not performed in patients with a
hemoglobin level < 11 g/dL.
 Phlebotomies are repeated every 1-2 weeks until a serum
ferritin level < 500 ng/mL.
 Iron removed in the single phlebotomy is calculated by
multiplying the volume of the phlebotomy by hemoglobin
concentration by 3.4.
Biol Blood Marrow Transplant 2010 June: 16(6): 832-7 Epub 2010 Jan 14.
A prospective study of iron overload management in allogeneic hematopoietic
cell transplantation survivors

30. SIDE EFFECTS/TOXOCITYDOSINGDRUG
Retinal/optic nerve damage
High frequency hearing loss
Local reactions
Growth retardation
(all rare at doses<125mg/kg)
20-50 mg/kg s.q. over
8-12 hrs
40-180 mg/kg i.v. over
8-12 hrs (high risk)
Deferoaxmine
(Desferal)
Renal tubular damage/proteinuria
Skin Rash
10-40 mg/kg/day poDeferasirol
Agranulocytosis (0.6%)
Neutropenia (6%)
Arthropathy (6-39%)
Zinc deficiency (1%)
Change in LFTs (44%)
Worsened liver fibrosis (?Hep C)
75 mg/kg/day in
divided doses po
Deferiprone
(L1)
CHELATION THERAPY

31. What we learned from Thalassemia patients
undergoing HCT
 No data for the natural evolution of iron overload following
HCT, or evidence regarding the benefit of depleting excess
iron stores on long-term morbidity and mortality.
 A gradual decline in liver iron stores has been reported in a
subgroup of children with thalassemia with no hepatomegaly
or hepatic fibrosis and adequate pretransplant chelation
therapy who were treated with allo HCT and became
transfusion independent
 Children cured of their thalassemia after allo HCT, but with
moderate to severe liver iron deposition pretransplant, tend to
have persistently elevated hepatic iron levels till more than 5
years after transplantation

32. Recommendation
 Patients with LIC less than 5–7 mg/ gm liver,DW)
and no iron-related organ toxicity can be observed
without treatment
 Patients with LIC of more than 7 mg /gm and/or
with suspected or proven iron-related hepatic or
cardiac dysfunction, phlebotomy or iron-chelation
therapy SHOULD be considered

33.  long-term follow-up guidelines recommend
screening with serum ferritin measurements at 1 year
post-HCT
 But no clear-cut guidelines for when to screen and
initiate therapy for iron overload
 Most studies use ferritin >1000

34.  A Prospective Study of Iron Overload Management
in Allogeneic Hematopoietic Cell Transplantation
Survivors June 2010Majhail NS,
Biology of Blood and Marrow Transplantation
Volume 16, Issue 6, June 2010, Pages 832-837

37. Change in serum ferritin concentration over 6 months of therapy in 3 patients
who received deferasirox for treatment of iron overload. LIC measured by liver
R2 MRI at baseline and at completion of 6 months of therapy is also shown.

38. Phlebotomy
 8 patients were considered for phlebotomy. They tolerated it well with
predictable decrease in serum ferritin level and did not require
interruptions
 16 patients with significant IO
 4 had end-organ damage due to iron overload.
 All 4 of these patients underwent phlebotomy. 2 patients (LIC, 9.0 and 22.8
mg/g) had liver function test abnormalities that improved after a reduction
of body iron stores. 1 patient had unexplained congestive heart failure (LIC,
15.8 mg/g) and 1 patient, who also had extensive chronic GVHD (cGVHD),
exhibited persistent liver function test abnormalities despite adequate
control of GVHD manifestations at other sites. The patient's serum ferritin
concentration at 13 months post-HCT was 4074 ng/mL, and his LIC on R2
MRI was 43.0 mg/g. Liver biopsy demonstrated cirrhosis. On further
evaluation, the patient was found to be homozygous for the C282Y
hemochromatosis gene mutation. He is currently undergoing phlebotomy
and has improving liver function test results.

39. Observation
 Five patients chose observation
 4/5 patients had decreasing serum ferritin over time.
 One patient underwent a follow-up R2 MRI for LIC
assessment. This patient exhibited significant
decreases in both serum ferritin concentration and
LIC, from 1599 ng/mL and 6.4 mg/g at baseline to
1019 ng/mL and 2.6 mg/g at 17-month follow-up.

40. Conclusions
 (1) phlebotomy is well tolerated in HCT survivors
and should be considered the treatment of choice
because of its relatively low cost and minimal risk of
side effects
 (2) deferasirox well tolerated and effective
alternative for the treatment of significant iron
overload in HCT survivors who cannot undergo
phlebotomy.
 (3)Serum ferritin concentration and LIC can
decrease without treatment in a subset of patients

41. Future directions
 Studying the efficacy of deferasirox post HCT in a
larger patient population
 The safety and feasibility of using deferasirox
concurrently with calcineurin inhibitors requires
further study.
 The natural history of iron overload in HCT
survivors, who receive RBC transfusions transiently
around the treatment of their hematologic
malignancy and HCT and then become transfusion-
independent.

42. References
• Bone Marrow Transplantation (2008) 41, 997–1003; doi:10.1038/bmt.2008.99;
published online 28 April 2008
Iron overload in hematopoietic cell transplantation
• Biology of Blood and Marrow Transplantation
Volume 16, Issue 1, January 2010 pages 115-122
Overload in Patients Receiving Allogeneic Hematopoietic Stem Cell Transplantation:
Quantification of Iron Burden by a Superconducting Quantum Interference Device
(SQUID) and Therapeutic Effectiveness of Phlebotomy
• Bone Marrow Transplantation (2009) 44, 793–797; doi:10.1038/bmt.2009.88;
published online 27 April 2009
Effect of iron overload and iron-chelating therapy on allogeneic hematopoietic SCT in
children
 Biol Blood Marrow Transplant 2010 June: 16(6): 832-7 Epub 2010 Jan 14.
A prospective study of iron overload management in allogeneic
hematopoietic cell transplantation survivors.

43. T H E B E S T W A Y T O T R E A T I R O N
O V E R L O A D ? ? ? ?