# Natural Killer (NK) Cell Alloreactivity in Haploidentical Stem Cell Transplantation

## TL;DR

This paper reviews how natural killer cell alloreactivity is studied in stem cell transplants between genetically half-matched donors and recipients.

## Contribution

The paper introduces and compares various models for predicting NK cell alloreactivity based on KIR and HLA interactions.

## Key findings

- KIR gene and receptor interactions are central to predicting NK cell alloreactivity.
- Multiple models, such as ligand–ligand and gene–gene, are used to assess donor-recipient compatibility.
- The optimal model for predicting alloreactivity and its role in donor selection remains under investigation.

## Abstract

This paper conducts a literature review on the role of natural killer cells in haploidentical hematopoietic stem cell transplantation. Theoretical concepts related to KIR genes are introduced regarding their structure, nomenclature, genetic organization, polymorphism, and inheritance pattern, types of KIR proteins and receptors, HLA ligands for KIR receptors, and the definition of different NK alloreactivity prediction models for the donor of haploidentical hematopoietic stem cell transplantation and the recipient. These models include the following and consider incompatibility: ligand–ligand, receptor–ligand, gene–gene, and KIR haplotype models or the KIR-B donor group. These models consider the presence or absence of specific ligands or receptors and/or KIR genes in the donor and recipient to predict alloreactivity. Determining the best model for predicting KIR alloreactivity and its significance in donor selection algorithms for haploidentical transplantation is still under investigation.