These computational approaches were applied to evaluate structural similarity and relative binding compatibility between cadherin-like peptides derived from hematophagous vectors and disease-associated <i>HLA-DRB1</i> alleles, including *04:02 and *14:01.<h4>Results</h4>HLA-DRB1*04:02 and HLA-DRB1*14:01 alleles were significantly enriched in PV patients compared with controls, and the heterozygous HLA-DRB1*04:02/14:01 genotype was overrepresented in the patient cohort. The gene discussed is CDH17; the disease is acquired polycythemia vera.