Serum micro RNA ‐122 kinetics in patients with chronic hepatitis C virus infection during antiviral therapy

Summary The levels of the liver‐specific micro RNA ‐122 (mi R ‐122) circulating extracellularly in the blood have been shown to be increased upon liver damage. However, it is unknown if the levels of serum mi R ‐122 are altered during antiviral therapy and reflect the therapeutic success. Here, we investigated mi R ‐122 serum levels in patients with chronic hepatitis C virus ( HCV ) genotype 1 infection during antiviral therapy with pegylated interferon and ribavirin. Therefore, sera from 60 patients with chronic HCV infection genotype 1 showing sustained virological response ( SVR ), non‐response or relapse to therapy obtained at baseline, 4, 12, 24 weeks, end of treatment and follow‐up were analysed retrospectively for mi R ‐122 content by quantitative real‐time reverse transcription PCR . The time courses of mi R ‐122 were correlated with HCV RNA as well as standard liver parameters. We found that while there was no relation between serum mi R ‐122 and HCV RNA levels at baseline, the decline in HCV RNA upon beginning of the therapy closely correlated with the reduction of serum mi R ‐122 in the three different patient groups. Moreover, the serum mi R ‐122 level correlated well with alanine aminotransaminase, a marker of ongoing liver damage. At follow‐up serum mi R ‐122 levels remained low in SVR , but increased to baseline levels in patients not responding or showing relapse to therapy. In contrast, the serum concentration of the ubiquitously expressed mi R ‐16 did not change during therapy. We conclude that the serum level of mi R ‐122 well reflects the success of interferon/ribavirin therapy in patients with chronic HCV infection.