Cord Blood HLA Matching and Compatibility 1 — Questions and Answers
Question 1: What does HLA stand for in the context of cord blood transplantation?
- Human Leukocyte Antigen (Correct answer)
- Human Lymphocyte Association
- Hematopoietic Leukocyte Antigen
- Hemoglobin Leukocyte Antibody
Correct answer: Human Leukocyte Antigen
HLA stands for Human Leukocyte Antigen, the system of proteins on cell surfaces that the immune system uses to distinguish self from non-self.
Question 2: What is the minimum HLA match typically required for a cord blood unit to be considered for transplantation?
- 3/6 match
- 4/6 match (Correct answer)
- 5/6 match
- 6/6 match
Correct answer: 4/6 match
A minimum 4/6 HLA match is typically required for cord blood transplantation, permitting more mismatches than adult unrelated donor transplants.
Question 3: On which chromosome is the major histocompatibility complex (MHC), which encodes HLA genes, located?
- Chromosome 1
- Chromosome 6 (Correct answer)
- Chromosome 9
- Chromosome 17
Correct answer: Chromosome 6
The MHC, which encodes HLA genes, is located on the short arm of chromosome 6.
Question 4: What is the term for the set of HLA alleles inherited together as a unit from one parent?
- Genotype
- Phenotype
- Haplotype (Correct answer)
- Karyotype
Correct answer: Haplotype
A haplotype is the combination of HLA alleles located on a single chromosome and inherited together from one parent.
Question 5: Which HLA class presents intracellular peptides primarily to CD8+ cytotoxic T cells?
- Class I (HLA-A, B, C) (Correct answer)
- Class II (HLA-DR, DQ, DP)
- Class III
- Both Class I and Class II equally
Correct answer: Class I (HLA-A, B, C)
HLA Class I molecules (HLA-A, B, C) are expressed on nearly all nucleated cells and present peptides to CD8+ cytotoxic T lymphocytes.
Question 6: What immune reaction occurs when donor T cells recognize and attack the recipient's tissues after cord blood transplantation?
- Host-versus-graft disease
- Graft-versus-host disease (GvHD) (Correct answer)
- Autoimmune hemolytic anemia
- Hyperacute rejection
Correct answer: Graft-versus-host disease (GvHD)
Graft-versus-host disease (GvHD) occurs when donor T cells in the cord blood graft recognize recipient tissues as foreign and mount an immune attack.
Question 7: Why does cord blood transplantation tolerate greater HLA mismatch compared to adult donor transplants?
- Cord blood contains no T cells
- Cord blood T cells are immunologically naive and less alloreactive (Correct answer)
- Cord blood is always from a related donor
- Cord blood units contain higher total nucleated cell counts
Correct answer: Cord blood T cells are immunologically naive and less alloreactive
Cord blood T cells are immunologically naive at birth and have reduced alloreactivity, allowing the immune system to tolerate HLA mismatches better.
Cord Blood HLA Matching and Compatibility 1
What does HLA stand for in the context of cord blood transplantation?