Allele-to-Antigen Equivalents (Page 1)

• Antigen equivalents are often memorized for common allele-to-antigen mappings. The following table lists alleles and their antigen/serologic equivalents:

  • $B^{*}14:01 \rightarrow B64$
  • $B^{*}14:02 \rightarrow B65$
  • $B^{*}15:01 \rightarrow B62$
  • $B^{*}15:02 \rightarrow B75$
  • $B^{*}15:03 \rightarrow B72$
  • $B^{*}15:10 \rightarrow B71$
  • $B^{*}15:12 \rightarrow B76$
  • $B^{*}15:13 \rightarrow B77$
  • $B^{*}15:16 \rightarrow B63$
  • $B^{*}15:42 \rightarrow B15$
  • $B^{*}40:01 \rightarrow B60$
  • $B^{*}40:02 \rightarrow B61$
  • $C^{*}03:02 \rightarrow Cw10$
  • $C^{*}03:03 \rightarrow Cw9$
  • $DRB1^{*}03:01 \rightarrow DR17$
  • $DRB1^{*}03:02 \rightarrow DR18$
  • $DQB1^{*}03:01 \rightarrow DQ7$
  • $DQB1^{*}03:02 \rightarrow DQ8$
  • $DQB1^{*}03:03 \rightarrow DQ9$

• There are multiple other alleles with unexpected antigen equivalents; some examples are shown in the next table. In addition, some alleles do not have clear antigen equivalents and may be undefined or have a combination of antigens. The HLA Dictionary should be consulted when determining antigen equivalents. Examples include:

  • $A^{*}24:10 \rightarrow A2403/A24$
  • $A^{*}32:04 \rightarrow A32/A3$
  • $B^{*}13:03 \rightarrow B49/B15$
  • $B^{*}15:08 \rightarrow B75/62$
  • $B^{*}15:09 \rightarrow B70$
  • $B^{*}40:26 \rightarrow B21$
  • $B^{*}50:02 \rightarrow B45$
  • $B^{*}55:07 \rightarrow B54$
  • $B^{*}56:10 \rightarrow B55$
  • $DRB1^{*}11:17 \rightarrow DR14$
  • $DRB1^{*}14:15 \rightarrow DR8$

• Source and notes:

  • Antigen equivalents are from the “expert defined” specificities in Holdsworth, R. et al. The HLA dictionary 2008: a summary of HLA‑A, ‑B, ‑C, ‑DRB1/3/4/5, and ‑DQB1 alleles and their association with serologically defined HLA‑A, ‑B, ‑C, ‑DR, and ‑DQ antigens. Tissue Antigens 73:95, 2008. Article available online at: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1399-0039.2008.01183.x

Serological Broad and Split Antigens (Page 2)

• Concept: Serological antigens are organized into Broad antigens (serologically defined groups) and their corresponding splits (more specific serologic antigens). The following mappings show which splits are associated with each broad antigen.

• Broad antigen: A2

  • Splits and associated antigens: A203, A210

• Broad antigen: A9

  • Splits: A23, A24, A2403

• Broad antigen: A10

  • Splits: A25, A26, A34, A66

• Broad antigen: A19

  • Splits: A29, A30, A31, A32, A33, A74

• Broad antigen: A24

  • Splits: A2403

• Broad antigen: A28

  • Splits: A68, A69

• Broad antigen: Cw3

  • Splits: Cw9, Cw10

• Broad antigen: B5

  • Splits: B51, B52, B5102, B5103

• Broad antigen: DR1

  • Splits: DR103

• Broad antigen: B7

  • Splits: B703

• Broad antigen: DR2

  • Splits: DR15, DR16

• Broad antigen: B12

  • Splits: B44, B45

• Broad antigen: DR3

  • Splits: DR17, DR18

• Broad antigen: B14

  • Splits: B64, B65

• Broad antigen: DR5

  • Splits: DR11, DR12

• Broad antigen: B15

  • Splits: B62, B63, B75, B76, B77

• Broad antigen: DR6

  • Splits: DR13, DR14, DR1403, DR1404

• Broad antigen: B16

  • Splits: B38, B39, B3901, B3902

• Broad antigen: DR14

  • Splits: DR1403, DR1404

• Broad antigen: B17

  • Splits: B57, B58

• Broad antigen: DQ1

  • Splits: DQ5, DQ6

• Broad antigen: B21

  • Splits: B49, B50, B4005

• Broad antigen: DQ3

  • Splits: DQ7, DQ8, DQ9

• Broad antigen: B22

  • Splits: B54, B55, B56

• Data source: Data is from the “HLA nomenclature” website at http://hla.alleles.org/antigens/broads_splits.html

• Practical note: These broad/split mappings are relevant for interpreting serologic results in transplantation and other HLA-typing contexts. The exact splits can be used to infer more precise antigen specificities when broad reactivity is observed.

• References to source material:

  • JOINT EDUCATIONAL INITIATIVES-TECHNOLOGISTS’ AFFAIRS CERTIFICATION EXAM STUDY GUIDE PART 3 - SHORT STUDY MATERIALS July, 2021