Altered lymphocyte phenotypes and proliferative responses in chimpanzees infected with hepatitis C virus

Hepatitis C virus RNA in peripheral blood mononuclear cells: relation with response to interferon treatment

The polymerase chain reaction (PCR) was used to investigate the presence of positive and negative hepatitis C virus (HCV) RNA strands in serum and peripheral blood mononuclear cells (PBMC) of 20 patients with histologically proven HCV-related chronic liver disease. All patients completed a course of interferon (IFN) treatment (6 MU of IFN-alpha 2b three times a week for 24 weeks) and were followed-up for 12 months after treatment was discontinued. Pre-treatment, end-treatment and 6-month follow-up serum and PBMC samples were examined. At enrollment, the positive strand of HCV-RNA was detected in serum of 18 patients (90%), the negative strand in none. Positive-stranded HCV-RNA was detected in PBMC of 15 patients (75%), 13 of whom also had detectable levels of negative-stranded HCV-RNA in PBMC. By the end of the treatment, 12 patients (60%) were responders. The pre-treatment HCV infection of PBMC, indicated by the presence of both RNA strands, was found in 8 (66.7%) responders compared to 5 (62.5%) non-responders (P = n.s.). End-treatment loss of PBMC HCV-RNA correlated significantly with the response since it occurred in all responders compared to 2 non-responders (P = 0.02). However, end-treatment-negative serum and PBMC HCV-RNA did not predict the occurrence of a sustained response, which was observed at month 12 in 5 of 12 responders (P = n.s.). On the other hand, the persistent absence of HCV RNA in serum and PBMC at the end of the 6-month follow-up was significantly associated with the occurrence of a sustained response (P < 0.0001).

Hepatitis C virus infection of mononuclear cells from peripheral blood and liver infiltrates in chronically infected patients

The mechanisms underlying chronicity of hepatitis C virus (HCV) infection are poorly understood, but the importance of impaired viral clearance by the immune system has been suggested. The prevalence of HCV infection of peripheral blood mononuclear cells (PBMC) was in investigated in 34 persistently infected patients with anti-HCV (7 with liver cirrhosis, 10 with chronic active hepatitis, 5 with chronic persistent hepatitis, 4 with chronic lobular hepatitis, and 8 healthy carriers) by polymerase chain reaction (PCR). HCV infection of 116 T cell clones derived from liver infiltrating mononuclear cells obtained from 3 patients with chronic liver disease was examined using the same methods. HCV genomic sequences were found in fresh, unstimulated PBMC from 20 patients with cirrhosis, and chronic active and persistent hepatitis, but in none of the healthy carriers and only in mitogen-activated cells from 1 out of 4 patients with autoresolving chronic lobular hepatitis. Active PBMC infection was confirmed by identification of anti-genomic HCV sequences in the majority of HCV RNA-positive cells (fresh or mitogen-stimulated). A high percentage of T cell clones obtained from liver infiltrates were found to be infected by HCV. These findings suggest that HCV infection of lymphatic cells plays a role in the pathogenesis of chronically evolving liver damage. PBMC may represent a reservoir for latent infection and a site for viral multiplication.