WITHDRAWN: Natural Killer Cell Activating Receptor NKG2D Is Involved in the Immunosuppressant Effect of Mycophenolate Mofetil and Infection of Hepatitis B Virus

Delay expression of NKp30 on NK cells correlates with long-term mycophenolate mofetil treatment and higher EBV viremia post allogenic hematological stem cells transplantation

Mycophenolate mofetil (MMF) is an immunosuppressive agent that is widely used in graft-versus-host disease prophylaxis because of its inhibitory function on T cells and B cells. However, the effect of MMF on natural killer cell reconstitution after allogenic hematological transplantation is largely unknown. The present study examined the effects of different MMF administration durations after haploidentical allo-HSCT on NK cell reconstitution. Ninety patients were enrolled in this study and defined into two groups in term of MMF duration. We found that MMF patients in the long-term MMF group were associated with a poor reconstitution of NK cells and a significantly lower cytotoxicity from day 30 to day 180 post-transplantation. Especially, the long-term MMF group inhibits reconstitution of NKp30 NK subsets, which correlated with higher risk of EBV viremia. Multivariate analysis showed that a better reconstitution of NKp30 cells was associated with lower EBV viremia (HR0.957, p = .04). In vitro experiments demonstrated that the active metabolite of MMF, mycophenolic acid (MPA), inhibited the proliferation and cytotoxicity of NK cells from healthy donors or patients at day 30 post-transplantation. In summary, our findings demonstrated that long-term MMF administration delayed the quality and quantity of NK cells, especially NKp30 subpopulations, which was associated with decreased EBV viremia post allogeneic HSCT.

Circulating NK cells and their subsets in Behçet's disease

Behçet's disease (BD) is an autoinflammatory, chronic relapsing/remitting disease of unknown aetiology with both innate and acquired immune cells implicated in disease pathogenesis. Peripheral blood natural killer (NK) cells and their CD56^Dim /CD56^Bright subsets were surface phenotyped using CD27 and CD16 surface markers in 60 BD patients compared to 60 healthy controls (HCs). Functional potential was assessed by production of interferon (IFN)-γ, granzyme B, perforin and the expression of degranulation marker CD107a. The effects of disease activity (BD^Active versus BD^Quiet ) and BD medication on NK cells were also investigated. Peripheral blood NK cells (P < 0·0001) and their constituent CD56^Dim (P < 0·0001) and CD56^Bright (P = 0·0015) subsets were depleted significantly in BD patients compared to HCs, and especially in those with active disease (BD^Active ) (P < 0·0001). BD patients taking azathioprine also had significantly depleted NK cells compared to HCs (P < 0·0001). A stepwise multivariate linear regression model confirmed BD activity and azathioprine therapy as significant independent predictor variables of peripheral blood NK percentage (P < 0·001). In general, CD56^Dim cells produced more perforin (P < 0·0001) and granzyme B (P < 0·01) expressed higher CD16 levels (P < 0·0001) compared to CD56^Bright cells, confirming their increased cytotoxic potential with overall higher NK cell CD107a expression in BD compared to HCs (P < 0·01). Interestingly, IFN-γ production and CD27 expression were not significantly different between CD56^Dim /CD56^Bright subsets. In conclusion, both BD activity and azathioprine therapy have significant independent depletive effects on the peripheral blood NK cell compartment.

DKK3 attenuates the cytotoxic effect of natural killer cells on CD133+ gastric cancer cells

Cancer stem cell (CSCs) has started a new era in cancer research. CD133 is a widely used marker for identification of CSCs. More and more studies showed that NK cells preferentially target cancer stem-like cells. However, the deeper mechanism of the susceptibility of cancer stem cells to NK cells remains unclear. In this study, we isolated CD133 positive population of a gastric cancer cell line, BGC823 cells, and cultured with NK cells. We found that CD133 could efficiently active NK cells in an NKG2D-dependent manner. DKK3 has been demonstrated as a suppressor in many cancers. Interestingly, we found that DKK3 suppressed CD133-induced activation in NK cells by inhibiting Erk pathway and immunological synapse (IS) formation. NK cells-based CSCs immunotherapy may be a novel approach for cancer therapy.