The ASCO Post is pleased to present Hematology Expert Review, an ongoing feature that quizzes readers on issues in hematology. In this installment, Dr. Abutalib, of Cancer Treatment Centers of America in Zion, Illinois, and Dr. Fleischhauer, of the Institute for Experimental Cellular Therapy at University Hospital Essen in Essen, Germany, explore the challenge of donor selection for human leukocyte antigen (HLA)-matched hematopoietic cell transplantation in a 33-year-old man with acute myeloid leukemia and complex cytogenetics.
Case Study
A 33-year-old white male is diagnosed with acute myeloid leukemia (AML) with complex cytogenetics. A decision is made in favor of performing allogeneic hematopoietic cell transplantation in first complete remission. The patient has a 35-year-old brother who is healthy and motivated to help with human leukocyte antigen (HLA) typing and hematopoietic graft procurement.
Question 1
Which statement about donor selection for allogeneic hematopoietic cell transplant is correct?
A. The first choice should be given to an HLA-mismatched related donor.
B. Even if a donor is potentially available, the HLA type of the patient’s parents is not of interest if the brother is matched at least for HLA-A, HLA-B, HLA-DRB1 at low resolution (first field).
C. If a donor is available, the genotypic identity between the patient and his brother should be established by typing the patient’s parents; if this is not possible, the brother should be HLA-matched at a minimum for HLA-A, HLA-B, HLA-C, and HLA-DRB1 at high resolution (second field).
Question 2
Which statement about the concept of linkage disequilibrium within the HLA system is correct?
A. Linkage disequilibrium means that certain alleles occur together with a lower frequency than expected by chance.
B. Linkage disequilibrium is not observed between loci that are in close proximity.
C. Linkage disequilibrium implies that certain alleles occur together with a higher frequency than expected by chance.
Question 3
Which of the following unrelated donors would be the first choice for allogeneic hematopoietic cell transplantation?
A. HLA-A, HLA-B, HLA-C matched at the antigen level and HLA-DRB1 matched at the allele level with the recipient.
B. HLA-A, HLA-B, HLA-C, and HLA-DRB1 matched at the antigen level with the recipient.
C. HLA-A, HLA-B, HLA-C, and HLA-DRB1 matched at the allele level with the recipient.
Question 4
Which statement about high-resolution (second field) HLA typing is correct?
A. High-resolution HLA typing cannot be performed on a peripheral blood specimen.
B. High-resolution HLA typing provides information regarding the allele group but not the specific HLA protein.
C. High-resolution HLA typing defines sets of alleles that encode the same protein sequence for the HLA molecule’s antigen-binding site.
Question 5
Which statement would be correct if multiple HLA-matched (eight of eight) unrelated donors were available?
A. Non-HLA factors would not influence donor selection.
B. HLA-DPB1 matching status would be considered to identify permissive mismatches.
C. Donor-specific antibodies in the recipient sera would not be a relevant finding.
Answers to Hematology Expert Review Questions here
