Dr. KK believes that elevated TNF causes implantation failure. This was the case for me, though I also had NK spikes once pregnant (treated with IL). There are many other cell subsets that can cause problems. Part of what impact your NK are your KIR, which is genetic. So you might not have a problem there but there can certainly be other areas causing issues for you. Thrombophilia also fits into this category. If you haven't been evaluated for ANA, APS, etc then that is another area to explore.

Is there anyone out there who had no issues with NK cells but were found to have other issues that stopped them from getting pregnant?