INTERFERON-GAMMA RECEPTOR EXPRESSION IN CHRONIC HEPATITIS-B VIRUS-INFECTION

It is known that interferon-gamma (IFN-gamma) is not effective in inducing a sustained inhibition of HBV replication in patients with chronic HBV infection in contrast to interferon-alpha (IFN-alpha). To determine whether this was related to IFN-gamma receptor (IFN-gamma-R) underexpression, binding characteristics of IFN-gamma to peripheral blood lymphocytes were studied in chronic HBV infection using radioiodinated recombinant IFN-gamma. Peripheral blood lymphocytes from patients with chronic HBV infection (n = 20), normal healthy controls (n = 12) and patients with non-viral related chronic liver disease expressed a similar number of IFN-gamma-R (medians (ranges): 1891 (1581-2515); 1916 (1589-2441); 1893 (1692-2104) sites/cell, respectively, p = N.S.) with a similar dissociation constant (K(d) almost-equal-to 0.7-2.7 nM). There was no correlation between IFN-gamma-R expression and serum transaminase, serum HBsAg and HBV-DNA titres and liver histology. IFN-alpha therapy in vivo also did not enhance IFN-gamma-R expression (n = 3). There is therefore, no evidence from this data that IFN-gamma-R is underexpressed in patients with chronic HBV infection to account for the difference in clinical response to these two forms of therapy.