Compromised natural killer cells in pulmonary embolism

The high morbidity, mortality and misdiagnosis rate render pulmonary embolism (PE) as a worldwide health problem. However, the etiology and pathogenesis of this disease have not been well characterized. Increasing studies indicate infection and immunity play a crucial role in PE. Natural killer (NK) cells act as a bridge between the innate immune and acquired immune. This study aimed to investigate the possible function of NK cells in PE.

Human cDNA microarray analysis was employed to detect genes associated with NK cells in peripheral blood mononuclear cells (PBMCs). Random variance model corrected t-test was used for statistical analysis of differential gene expression. Flow cytometry was performed to detect the CD16+CD56+ NK cells.

In the present study, based on gene expression microarray analysis, we showed four inhibitory receptors (KLRB1, KLRD1, KLRF1, KLRG1) and four activating receptors (KLRC1, KLRC3, KLRK1 and NCR1) on NK cells were remarkably down-regulated and the cytological experiment demonstrated the proportion of CD16+CD56+ NK cells among PBMCs decreased in the PE group.

We confirmed the presence of reduced expression of critical activating as well as inhibitory NK cell receptors and low proportion of CD16+CD56+ NK cells in PE. The consistence between genomic and cytological examination suggests compromised NK cells may contribute to the pathogenesis of PE.