Human participants affected with sickle cell disease or thalassemia will donate bone marrow
for use in experimental laboratory models to study potential new treatments. This is an
observational study using bone marrow from human participants. The investigators will use
sickle cell and thalassemia mouse models to observe and evaluate the possibility of
correcting these disorders through genetic alterations or drug treatment.
These studies are designed to evaluate the potential of retroviral vector mediated gene
transfer, gene editing, or drug treatment to correct the pathophysiology of sickle cell
anemia and β-thalassemia. CD34+ cells purified from bone marrow of research participants with
a sickle cell syndrome or a thalassemia syndrome will be subjected to genetic editing, drug
treatment, or transduced with retroviral vectors containing γ-globin coding sequences under
the control of the β-globin gene promoter and including various regulatory elements chosen to
enhance gene expression and to insulate regulatory elements from cellular genes at or near
the integration sites. The efficiency of gene transfer and the function of the globin
transgene will be evaluated in erythroid cells derived from transduced progenitors and from
the progenitors in the bone marrow of immunodeficient mice engrafted with transduced,
primitive hematopoietic cells. The hypothesis to be tested in this research is that a gene
therapy vector, gene editing strategy, or drug modality can be designed to achieve a
potentially therapeutic level of globin gene expression in maturing erythroid cells.
- Patients with homozygous S/S disease or doubly heterozygous for S and β thalassemia
who are 2 years or older are eligible. Patients with HbE- β- thalassemia or homozygous
(severe) β-thalassemia are also eligible. Patients with thalassemia include those who
are transfusion dependent (major) or severely anemic but relatively transfusion
independent (intermedia). Diagnostic criteria include standard hematological
parameters, red cell indices, hemoglobin electrophoresis and quantitative
determination of HbF and HbA2.
- Patients are eligible for participation in the protocol only if they are currently
clinically stable and have been free of all acute disease manifestations for a minimum
of 14 days.
- Patients may participate while continuing their current therapeutic regimen including
regular transfusion therapy or hydroxyurea administration.
- In general, two categories of patients will be considered as research participants in
1. Patients who are 18 years or older and therefore able to provide informed consent
will be eligible. Such individuals will be recruited from among patients followed
at SJCRH. In addition, individuals followed in an outside clinic who are
recruited will be asked to come to the Hematology Clinic at SJCRH to enroll and
have the procedure performed. Alternatively, if a patient who is 18 or older is
to undergo a diagnostic or surgical procedure under general anesthesia, and they
agree to participate in the study, the bone marrow aspirate will be obtained at
2. Patients between the ages of 2 and 17 years who are scheduled for a diagnostic or
surgical procedure at SJCRH or LeBonheur Children's Medical Center for which
sedation or general anesthesia is indicated will be eligible for protocol
enrollment. A bone marrow aspiration will be performed during the sedation or
general anesthesia for the diagnostic or surgical procedure.
- Active, acute manifestations of sickle cell disease including painful crisis, acute
chest syndrome, cerebrovascular events or active infection.
- Pregnant women will not be eligible for study enrollment.
- Inability or unwillingness of the research participant or legal
guardian/representative to give written informed consent will preclude enrollment on
this research protocol.
- Platelet count < 150,000/mm^3
- Neutrophil count < 2000/mm^3 (unless on hydroxyurea therapy)
- Neutrophil count < 1000/mm^3 for patients on hydroxyurea therapy
- Prothrombin Time > 17 seconds
- Partial thromboplastin Time > 43 seconds
- History of excessive bleeding in the context of previous procedures including surgery
and dental extractions
Mitchell J. Weiss, MD, PhD
St. Jude Children's Research Hospital
Mitchell J. Weiss, MD, PhD