The aim of our study was to perform a separate analysis of hepatitis B vaccinated and HBV infected HD patients in relation to the polymorphic variants of IL12A G>A (rs568408) and IL12B A>C (rs3212227) and to assess whether in HD patients polymorphic variants of IL-12 are equally associated with the development of anti-HBs in the event of HBV vaccination or HBV infection. The gene discussed is IL12B; the disease is hepatitis B virus infection.