The genotypes C/T (TLR5 R392StopCodon) and T/T (TLR9 -1486C/T) appear to be risk factors for Pv-infection (TLR5: C/C vs. C/T OR = 2.1 [95% CI: 1.1–4.5, p = 0.031]; TLR9: C/C vs. T/T OR = 1.9, [95% CI: 1.2–3.2, p = 0.01]; TLR9: C/C vs. C/T+T/T OR = 1.6, [95% CI: 1.1–2.5, p = 0.024]). This evidence concerns the gene TLR5 and acquired polycythemia vera.