Autori: Onofrio Schillaci, Gioacchino Li Cavoli, Franca Servillo, Carmela Zagarrigo, Angelo Tralongo, Carlo Giammarresi, Barbara Oliva, Camillo Carollo, Rosanna Turdo, Vitalba Azzolina, Antonio Amato, Rosy Mongiovì.
Affiliazioni: UOC Nefrologia Dialisi Trapianto Renale
The isolated finding of HBcAb in HBsAg-negative subjects is considered marker of past exposure to HBV and resolved infection but the use of sensitive techniques to detect HBV-DNA has shown that low levels of viremia are detectable in HBsAg-negative/HBcAb -positive subjects. Today emigration from countries where HBV is highly prevalent result in HBsAg-negative patients with past HBV-exposure who may develop ESRD entering the dialysis-pool. We investigated thef HBV infection in 322 HD patients from 01/2016 to 06/2017. Among these patients, we found 6 HBsAg-positive (1.8 %) (2 with HCV- and 1 with HIV-coinfection; 2 patients were migrant from Africa); all HBsAg-positive patients had history of transfusion but not of illicit drugs abuse. Among the remaining 316 HBsAg-negative patients, we found 56 HBcAb-positive (18%) and 59 HBsAb-positive (19%) patients; 32 (10%) had mixed HbsAb/HBcAb-positivity; no positive case of IgM-HBcAb-, HBeAg- or HBeAb-positive was detected; 311 patients were Caucasian; 3 were migrant from Africa, 2 were migrant from Bangla Desh. 
Data from Regional Italian Registries on HBsAg-positivity in HD patients range in 0.6-2.2 %. HBcAb is a long-life serological marker of previous HBV infection and it is found in chronic infection as well in subjects who recover from infection. In Italy prevalence of HBsAg-negative/HBcAb-positive subjects among first-time blood donors is 4,85 -8,3 % . The presence of HBcAb in HBsAg-negative/HBsAb-negative subjects is considered an important key for occult HBV infection tracking in general population, in HD patients and in renal transplant recipients. The relevant HBcAb-positivity rate in HD patients highlights the ongoing risk of HBV spread in HD facilities.