[Immune reconstruct regularity profile of KIR2DL1 and KIR3DL1 in unrelated-donor allogeneic hematopoietic stem cell transplantation]

Dynamic mRNA expression of donor-derived activating KIR genes and their significant effects on clinical outcome after haematopoietic stem cell transplantation

Numerous reports suggest that activating killer immunoglobulin-like receptors (aKIRs) of natural killer (NK) cells, in addition to inhibitory KIRs (iKIRs), play a prognostic role after allogeneic haematopoietic stem cell transplantation (allo-HSCT). We aimed to investigate the association between the dynamic expression of KIRs on NK cells and the outcomes, particularly regarding graft-versus-host disease (GvHD). This study retrospectively enrolled 260 pairs of donors and recipients who had undergone allo-HSCT without in-vitro T cell depletion. The mRNA transcription level of KIRs was determined by quantitative real-time polymerase chain reaction (RT-qPCR). The levels of aKIR transcripts were decreased more than those of iKIRs during the occurrence of GvHD. The transcription levels of KIR2DS2 and KIR2DS4 in the patients developing GvHD, compared with those who were at a tolerance state, showed the most significant decrease in the month at their peak transcription levels (p = 0.03, p = 0.002). Significantly decreased expression of KIR2DS1 (p = 0.02), KIR2DS3 (p = 0.04) and KIR2DS5 (p = 0.04) in the GvHD group was observed when the transcription level reached a maximum. High expression of KIR3DS1 was associated with superior overall survival (OS) (p < 0.001). The expression of KIR2DS4 in the KIR genotype Bx group decreased more during GvHD, particularly at 3M (p = 0.02). These findings suggest that KIR genes are potential post-HSCT biomarkers and dynamic changes in the KIR transcription levels can be detected to better predict the occurrence and evaluate the treatment of GvHD after transplantation.

Study of KIR gene expression at the mRNA level in specific donor-derived NK cells after allogeneic HSCT

The function of natural killer (NK) cells after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is regulated by the balance between inhibitory KIRs (iKIRs) and activating KIRs (aKIRs). However, few studies have examined the subsequent expression of KIR genes unique to the donor. We defined the set of KIR genes expressed only in the donor and designed a method for measuring the expression of these KIR genes by quantitative real-time polymerase chain reaction (RT-qPCR) based on genetic cloning techniques. In this study, we evaluated the recovery pattern of KIR genes in 252 donor-recipient pairs. The expression of each KIR unique to the donor was in line with that of KIR genes shared by the donor and recipient, such as KIR2DS1, KIR3DS1, KIR2DS4, or KIR2DS3. The timing of the peak mRNA expression of aKIRs unique to the donor was inconsistent but occurred within the first 3 months posttransplantation, whereas the peak mRNA expression of iKIRs was consistently observed in the third month after transplantation. The expression of KIR2DL2 in the third month posttransplantation was significantly higher in the transplant recipients than in the donors (p = 0.01). The KIR2DL1 and KIR3DL1 levels in the transplant recipients in the second and third months posttransplantation were also obviously higher than the donor levels (p < 0.0001). Thus, these observations should be considered when attempting to predict the correlation between mRNA expression and prognosis after allo-HSCT.