Role of NK cells in immune escape in patients with classical paroxysmal nocturnal haemoglobinuria.

BACKGROUND

Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired clonal haematopoietic stem cell disorder. Immune escape is crucial in PNH, and our previous studies revealed that natural killer (NK) cells potential participate in the immune escape of PNH. This study aimed to investigate the subtypes and functional changes of NK cells in PNH patients.

METHODS

We analysed CD59+ and CD59- bone marrow mononuclear cells using single-cell RNA sequencing (scRNA-seq). The results were validated through flow cytometry and co-culture experiments.

RESULTS

We classified NK cells into seven subtypes by scRNA-seq, and found significant differences in the distribution of subtypes in CD59+ and CD59- NK cell of PNH patients. Compared with controls, the proportion of active and adaptive NK cells was higher in CD59+ NK cells. Conversely, the proportion of CD56bright NK cells and terminal NK cells was elevated in CD59- NK cells. Additionally, the proportion of mature NK cells decreased in both the CD59+ and CD59- groups. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis revealed impaired function of CD59- NK cells, whereas CD59+ NK cells showed minimal change. Furthermore, similar results were verified by flow cytometry and co-culture in vivo and in vitro. And the proportion of NK cells was closely related to the proportion of CD8+ T cells and the clinical indicators of disease.

CONCLUSIONS

The quantity and function of NK cells in PNH patients are insufficient, in which CD59- NK cells have functional defects, whereas CD59+ NK cells were mainly activated and potential involved in immune escape by regulation of T cells.