Presence of TTV DNA in serum, liver and peripheral blood mononuclear cellsfrom patients with chronic hepatitis

The main site of TT virus (TTV) replication remains unknown. Therefore, we have studied the presence and titres of TTV DNA in paired serum, liver and PBMC samples from 50 patients with liver disease (32 with chronic hepatitis B or C, seven with cryptogenic hepatitis and 11 with nonviral liver diseas e) were included. TTV DNA was analysed by polymerase chain reaction (PCR) u sing primers from the open reading frame 1 (ORF 1) and from the untranslate d region (UTR) and titres were semiquantified by PCR using an external stan dard. TTV DNA was detected in 26% of serum, 24% of liver and 14% of PBMC sa mples with ORF 1 primers. When UTR primers were used, 70% of serum and live r samples and 64% of PBMC were TTV DNA positive. No differences between TTV positive and negative patients were found regarding epidemiological or bio chemical parameters. Trypsin treatment and fluorescent ill situ hybridizati on confirm the intracellular location of TTV in PBMC. The mean of TTV DNA t itres was statistically higher in liver than in serum or PBMC. TTV titres i n serum correlated with those In PBMC but not with those in liver. In concl usion, although the liver seems to be the main site for TTV replication, th is virus is also able to infect PBMC.