Serum levels of soluble tac peptide in acute and chronic hepatitis B virus infection

Serum-soluble Tac peptide was measured by an enzyme-linked immunosorbent assay in 12 patients with acute type B hepatitis, 33 patients with chronic type B hepatitis, and 15 age- and sex-matched controls. All 12 patients with acute type B hepatitis had elevated levels of soluble Tac peptide with a mean (±SD) of 1527 ± 432 U/ml, significantly higher than that of normal controls (264 ± 74 U/ml) or patients with chronic type B hepatitis (646 ± 399 U/ml). Serial follow-up showed that serum levels of soluble Tac peptide tended to return to normal 2-4 months after onset of acute hepatitis along with the normalization of alanine aminotransferase and seroconversion of hepatitis B surface antigen (HBsAg) to anti-HBs. Patients with chronic type B hepatitis also had significantly higher levels of soluble Tac peptide than normal controls, although only 63.6% ( 21 33) of them had a level greater than the upper limit of normal. Serum levels of soluble Tac peptide in patients with chronic type B hepatitis varied considerably with the inflammatity in liver. The hepatitis B e antigen (HBeAg)-positive patients with chronic active liver disease had significantly higher levels of soluble Tac peptide (928 ± 424 U/ml) than HBeAg-positive (412 ± 146 U/ml) or anti-HBe-positive (424 ± 175 U/ml) patients with chronic persistent hepatitis or minimal histological change. In addition, there was a significant positive correlation between serum levels of soluble Tac peptide and alanine aminotransferase. These findings suggested that activation of T cells might play an important role in the pathogenesis of acute and chronic type B hepatitis. Assay of serum-soluble Tac peptide might provide a simple and useful means to better understand the immune mechanisms of acute and chronic hepatitis B virus infection.