Cord Blood Cord Blood Stem Cells 2 — Questions and Answers
Question 1: What is the minimum total nucleated cell (TNC) dose per kilogram of recipient body weight typically required for successful cord blood engraftment?
- 1 × 10⁵ TNC/kg
- 2.5 × 10⁷ TNC/kg (Correct answer)
- 3 × 10⁶ TNC/kg
- 1 × 10⁸ TNC/kg
Correct answer: 2.5 × 10⁷ TNC/kg
A minimum of approximately 2.5 × 10⁷ total nucleated cells per kilogram of recipient body weight is generally required to achieve reliable engraftment.
Question 2: What is mixed chimerism following a cord blood transplant?
- 100% donor cells in the recipient
- A mixture of both donor and recipient blood cells coexisting (Correct answer)
- Complete rejection of donor cells
- Infection of the transplanted cells
Correct answer: A mixture of both donor and recipient blood cells coexisting
Mixed chimerism is a state where both donor-derived and recipient-derived blood cells coexist in the recipient after transplantation.
Question 3: How long can cord blood stem cells be stored cryogenically while maintaining viability?
- 5 years maximum
- 10 years maximum
- 25 years or more (Correct answer)
- Only 1 year
Correct answer: 25 years or more
Studies have confirmed that cord blood stem cells stored in liquid nitrogen at −196°C can remain viable for 25 years or more.
Question 4: What is ex vivo expansion of cord blood stem cells designed to overcome?
- HLA mismatching
- The limited cell dose in a single cord blood unit (Correct answer)
- GVHD risk
- Viral contamination
Correct answer: The limited cell dose in a single cord blood unit
Ex vivo expansion protocols aim to increase the total cell dose from a single cord blood unit, which is often insufficient for adult patients.
Question 5: Which cytokine combination is commonly used in ex vivo cord blood stem cell expansion protocols?
- IL-2 and IL-4
- SCF, TPO, and Flt3 ligand (Correct answer)
- TNF-alpha and IL-6
- G-CSF and erythropoietin alone
Correct answer: SCF, TPO, and Flt3 ligand
Stem cell factor (SCF), thrombopoietin (TPO), and Flt3 ligand are key cytokines used to promote ex vivo expansion of cord blood hematopoietic progenitors.
Question 6: What are mesenchymal stem cells (MSCs) found in cord blood primarily known for?
- Making red blood cells
- Their immunomodulatory properties and ability to differentiate into bone, fat, and cartilage (Correct answer)
- Producing antibodies
- Destroying cancer cells directly
Correct answer: Their immunomodulatory properties and ability to differentiate into bone, fat, and cartilage
Cord blood MSCs are multipotent stromal cells with strong immunomodulatory properties and the capacity to differentiate into mesodermal tissues such as bone, adipose, and cartilage.
Cord Blood Cord Blood Stem Cells 2
What is the minimum total nucleated cell (TNC) dose per kilogram of recipient body weight typically required for successful cord blood engraftment?