Genomic DNA will be obtained and will be studied in Professor Moffet laboratory in Cambridge (department of Pathologí, University of Cambridge) KIR typing including copi number and HLA-C loci will be performed as previously described (Hiby 2010, Jiang 2012). KIR haplotype regions will be defined by the presence of the following KIR genes: Cen-A/2DL3; Tel-A/3DL1 and 2DS4; Cen-B/2DL2 and 2DS2; Tel-B/2DS1 and 3DS1. The HLA-C ligands for KIRs will be divided into 2 groups: HLA-C1 and HLA-C2.