Hepatitis delta virus infection in chronically HBV-infected patients from northern Poland.

The objective of this study was to estimate the presence of hepatitis delta virus RNA in chronically HBV-infected patients from northern Poland. Three out of 63 studied samples (4.8%) were positive in a qualitative test for total antibodies to HDV antigen. Five samples (7.9%) turned out to be HDV-RNA-positive by RT-PCR, four of them were sequenced in the region of L-HDAg, and phylogenetic analysis was performed. All four examined samples belonged to genotype I. Two RNA-positive/anti-HD-negative samples possessed a few uncommon nucleotide substitution sites within the L-HDAg sequence, which could suggest unique variants in the Polish population of HDV-infected patients.