By comparing the distribution of PD-1.6 alleles among all HCV-related liver diseases (CHC, cirrhosis, and HCC) with HCV-related lymphoproliferative disorders (MC, NHL) a significantly higher frequency of A allele was found in the latter group (83/817 and 50/426, respectively, p = 0.018). Here, PDCD1 is linked to lymphoproliferative syndrome.