Clinical information
Diagnostic Utility:
High-resolution HLA typing allows us to determine the HLA typing at an allelic level (4 digits). Typing of the HLA-DRB3, HLA-DRB4, HLA-DRB5 loci is of special interest in donors to assess the presence of donor-specific antibodies in transplant patients. Additionally, typing of the HLA-DRB3 locus is applicable for the identification of the HLA-DRB3*01:01 allele associated with immunization against the platelet antigen HPA-1a in the context of neonatal alloimmune thrombocytopenic purpura (NAITP).
Method:
The PCR-NGS technique (Long strategy) allows for high-resolution HLA typing of class I and II HLA genes and non-classical HLA genes. This technique consists of several phases: amplification of the HLA genes of interest by PCR, library preparation, sequencing, and result analysis. With the Long strategy (long fragments), the complete gene sequencing is obtained, while with the Short strategy (short fragments), exons 2, 3, and 4 of the HLA-A, -B, -C genes and exons 2 and 3 of the HLA-DRB1, HLA-DRB3, HLA-DRB4, HLA-DRB5, -DQB1, -DPB1, -DQA1, and -DPA1 genes are sequenced.
Reference Values
HLA-DRB1 alleles are associated with one or no DRB3, DRB4, and DRB5 genes. By way of example, these could be some possible results that we could obtain for each gene when performing high-resolution HLA typing: HLA-DRB3*02:02, DRB4:01:03, DRB5*01:01.
Diagnostic Algorithm:
Not applicable.
Turnaround Time:
The turnaround time for high-resolution HLA typing depends on the sample source:
- Patient or family members of a patient candidate for hematopoietic stem cell transplantation (20 working days).
- Voluntary donor registry (20 working days).
- Expansion of HLA typing in voluntary donors (10 working days).
- Umbilical cord blood unit registry (20 working days).
- Umbilical cord blood unit verification (20 working days).
- Pre-transplant confirmation of donor and recipient (20 working days).
Specimen information
Sample: Whole blood
Tube: EDTA K3 4 ml tube
Minimum volume: 500µl.
Stability:
- In refrigeration: 2 weeks.
- At -20ºC: from 2 weeks onwards.
Transport instructions: Preferably at room temperature
Reason for rejection: Coagulated sample
Administrative information
BST Code: LRD2058A, LRD2058B, LRD2058C
Test Description: High resolution HLA-DRB3 / DRB4 / DRB5 typing
Synonyms: Not applicable
Section: Histocompatibility and Immunogenetics
BST Fee: Check the updated fees here.
Profiles: Not applicable.
References
Manual dels "Standards for Histocompatibility Testing" de l'EFI (darrera versió).