Follow-up of hepatitis C virus RNA in peripheral blood mononuclear cells during interferon therapy

Mononuclear cells can be infected in vitro by hepatitis C virus and the vir al RNA can be detected in mononuclear cells of chronically infected patient s. It was suggested that the virus could persist in the mononuclear cells o f some patients treated by interferon. The aim of this study was to follow the presence of viral RNA in the plasma and peripheral bleed mononuclear ce lls of 16 chronically infected patients treated by alpha2b interferon for 1 year. The RNA was detected by reverse transcription followed by nested PCR and quantified using the branched DNA method at regular intervals for at l east one year. Before PCR, the mononuclear cells were treated by RNase and trypsin in order to eliminate the viral particles that could be stuck at th e cell surface. Six patients were non responders and had persistent plasmat ic viral RNA during the treatment. Two patients were good responders and ha d persistantly negative PCR in both plasma and mononuclear cells. Eight pat ients had initial negativation of plasmatic hepatitis C virus RNA but showe d a relapse characterized by positive plasmatic PCR. Positive PCR in mononu clear cells despite negativity of plasmatic PCR was noted 18 times in 8 pat ients. Persistently positive PCR in mononuclear cells in absence of detecta ble viraemia was followed by a virological relapse in 5 of these patients. This study confirms that hepatitis C virus RNA can be detected in mononucle ar cells despite negative plasmatic PCR in patients treated by interferon. Moreover, the persistence of viral RNA in peripheral mononuclear cells coul d be a predictive factor of treatment failure. Our data also suggest that d etection of viral RNA in mononuclear cells is probably not only due to pass ive virus adsorption from plasma.