Skip to main content
. Author manuscript; available in PMC: 2017 Oct 1.
Published in final edited form as: Semin Hematol. 2016 Jul 25;53(4):230–236. doi: 10.1053/j.seminhematol.2016.07.003

Table 4.

Summary of HLA Mismatching in Unrelated Donor Hematopoietic Cell Transplantation

Validated data suggest that when HLA-matched donors are not available:

  1. Restrict the total number of HLA mismatches to one.

  2. Include HLA-DQB1 in your decision making because HLA-DRB1+DQB1 double mismatches are risky.

  3. When HLA-DRB1-matched donors are identified, assess DRB3, DRB4, DRB5 to uncover coincident mismatching at these loci; cumulative mismatching at these genes does increase risk after transplantation.

Emerging research suggests additional features may prove to be important in the future:

  1. Permissible HLA mismatches may be characterized on the basis of the amino acid substitutions and the level of HLA-C and DPB1 expression.

  2. Permissible HLA-C and HLA-DP mismatches may be characterized on the basis of the level of expression of the patient’s mismatched allotype.

  3. Regulatory regions of HLA genes not currently tested in routine clinical practice encode polymorphisms that define the level of HLA protein expression.