Genotype KIR

Clinical information

Diagnostic Utility:

NK cells have membrane receptors called KIRs, which can be activators or inhibitors. When evaluating a patient candidate for hematopoietic stem cell transplantation, the KIR genotype is a criterion to consider when there is more than one haploidentical family member as a potential donor. In patients with acute myeloid leukaemia, the prediction of NK cell alloreactivity, considering the KIR genotype and its ligands (HLA class I), has been associated with a lower relapse rate, lower incidence of graft-versus-host disease, and better survival.

On the other hand, in studies on infertility due to implantation failures, recurrent miscarriages, and preeclampsia, the study of KIR receptors and their ligands is requested. In egg donation treatments, different KIR-HLA-C combinations are evaluated to promote embryo implantation.

Method:

The KIR genotype can be studied using the following two detailed techniques:

PCR-NGS: Long-range PCR allows for the amplification of all HLA Class I genes (exons and introns) and the 16 KIR genes studied in a single tube. From these amplicons, libraries are prepared, sequencing is carried out, and the results are analysed.

PCR-SSO: KIR genes are amplified by PCR using biotinylated primers. The amplified products are hybridised with specific oligonucleotide probes immobilised on microspheres. Subsequently, the addition of a streptavidin-PE buffer allows visualisation of the hybridisation pattern using the LUMINEX system.

Reference Values

The results indicate the presence or absence of the studied KIR genes. The possible results for each KIR gene are: Negative or Positive. From this information, the KIR genotype is obtained. For example, KIR Haplotype: Bx (Genotype ID: 4).

In addition, two results are obtained for the HLA-A, -B, and -C genes with high-resolution typing, for example: HLA-A*02:01 A*26:01.

Diagnostic Algorithm:

Not applicable.

Turnaround Time:

15 working days.

Specimen information

Sample: Whole blood
Tube: 4 ml K3 EDTA tube
Minimum volume: 500 µl.

Stability:

• In refrigeration: 2 weeks.
• At -20°C: from 2 weeks onwards.

Transport instructions: Preferably at room temperature

Reason for rejection: Clotted sample.

Administrative information

BST Code: LRD2057
Test Description: KIR Genotype
Synonyms: Not applicable.
Section: Histocompatibility and Immunogenetics
BST Fee: Consult the updated fees here.
Profiles: Not applicable.

References

• Ruggeri L, Capanni M, Casucci M, Volpi I, Tosti A, Perruccio K, Urbani E, Negrin RS, Martelli MF, Velardi A. Role of natural killer cell alloreactivity in HLA-mismatched hematopoietic stem cell transplantation. Blood (1999) 91:333-9
• Manual dels "Standards for Histocompatibility Testing" de l'EFI (darrera versió).
• Closa L, Vidal F, Herrero MJ, Caro JL. Design and validation of a múltiplex KIR and HLA class I genotyping method using Next Generation Sequencing. Front Immunol (2018), 9:2991.