KLRC1 and chronic graft versus host disease: Considering all alloSCT patients or patients receiving a HLA-matched graft, patients with extended chronic GvHD (cGvHD) display significantly (p = 0.02 or p = 0.001) reduced proportions of NK cells bearing CD94/NKG2A during the observation period of the first year post-alloSCT when compared to patients with no or only limited cGvHD.