Decreased NK cell immunity in kidney transplant recipients late post-transplant and increased NK-cell immunity in patients with recurrent miscarriage.

There is evidence that NK-cell reactivity might affect graft outcome in transplant recipients and pregnancy in women.NK-cell subsets were determined in whole blood using eight-colour-fluorescence flow cytometry in patients before and after renal transplantation, patients with recurrent miscarriage (RM) and healthy controls (HC).Patients late post-transplant (late-Tx) with functioning renal transplants showed abnormally low CD56dimCD16+ NK-cells containing both perforin and granzyme (vs HC p = 0.021) whereas RM patients exhibited abnormally high numbers of these cells (vs HC p = 0.043). CD56dimCD16+perforin+granzyme+ NK-cell counts were strikingly different between the two patient groups (p0.05 and p = 0.016, respectively).NK-cells with lower cytotoxicity and immunoregulatory function might contribute to good long-term graft outcome, whereas circulating NK-cells with normal or even increased cytotoxicity and less immunoregulatory capacity are observed in patients with RM

Helios expression and Foxp3 TSDR methylation of IFNy+ and IFNy- Treg from kidney transplant recipients with good long-term graft function

<div><p>Background</p><p>There is circumstantial evidence that IFNy+ Treg might have clinical relevance in transplantation. IFNy+ Treg express IFNy receptors and are induced by IFNy. In the present study we investigated in kidney transplant recipients with good long-term stable graft function the absolute cell counts of IFNy+ Treg subsets and whether their expression of Foxp3 is stable or transient.</p><p>Method</p><p>Helios expression determined by eight-color-fluorescence flow cytometry and methylation status of the Foxp3 Treg specific demethylation region (TSDR) served as indicators for stability of Foxp3 expression. Methylation status was investigated in enriched IFNy+ and IFNy- Treg preparations originating from peripheral blood using high resolution melt analysis. A total of 136 transplant recipients and 52 healthy controls were studied.</p><p>Results</p><p>Proportions of IFNy+ Treg were similar in patients and healthy controls (0.05% and 0.04% of all CD4+ lymphocytes; p = n.s.). Patients also had similar absolute counts of IFNy producing Helios+ and Helios- Treg (p = n.s.). Most of the IFNy+ and IFNy- Treg in transplant recipients had a methylated Foxp3 TSDR, however, there was a sizeable proportion of IFNy+ and IFNy- Treg with demethylated Foxp3 TSDR. Male and female patients showed more frequently methylated IFNy+ and IFNy- Treg than male and female controls (all p<0.05).</p><p>Conclusions</p><p>Kidney transplant recipients with good long-term stable graft function have similar levels of IFNy+ Treg as healthy controls. IFNy+ and IFNy- Treg subsets in patients consist of cells with stable and cells with transient Foxp3 expression; however, patients showed more frequently methylated IFNy+ and IFNy- Treg than controls. The data show increased levels of Treg subsets with stable as well as transient Foxp3 expression in patients with stable allograft acceptance compared to healthy controls.</p></div

Surface CD107a and intracellular IFNy and perforin after in-vitro stimulation of NK-cells from patients and HC, association with graft outcome.

<p>(a) The increase of CD107a on NK-cells was strongly associated with a decrease of perforin+granzyme+CD56dimCD16+ NK-cells (= degranulation and perforin release of NK-cells). (b) The decrease of perforin+granzyme+CD56dimCD16+ NK-cells was associated with high GFR and good graft outcome suggesting an impaired capacity of NK-cells from patients late post-transplant to release perforin (p<0.05). (c) HC showed a stronger perforin release of NK-cells after in-vitro stimulation than graft recipients late-post-transplant (p<0.05). (d) NK-cells of patients late-post-transplant showed a stronger IFNy upregulation during in-vitro stimulation with the tumor cell line K562 than those of RM patients (p<0.05). (e) Low IFNy upregulation during in-vitro stimulation was associated with low upregulation of CD107a on the cell surface of NK-cells obtained from patients late post-transplant (p = 0.042).</p