Two of 6 controls contaminated with OP presented: one Control (C1) contaminated with diazinon and malathion presented both HLA-DRB1*01:01 and HLA-DQB1*05:01 alleles of susceptibility to PF, and another one (C5) contaminated with dichlorvos and chlorpyriphos presented HLA-DQB1*03:02 allele of susceptibility to PV. This evidence concerns the gene HLA-DQB1 and acquired polycythemia vera.