Y: Yes, N:No

Genomic DNA was extracted from whole blood samples using the PureLink Genomic DNA kit (Invitrogen) according to manufacturer’s protocol.

Genotyping of SNPs at promoter region of HLA-G and CpG41 ofHLA-DRB1 was performed with Pyrosequencing methodology (AQ and SQA assays), according to manufacturer’s protocols. PCR and sequencing primers used are presented in Table 2.