Background:  Clearance of hepatitis C virus (HCV) is attributed to host cellular immune responses, in which T helper cells play a critical role. The purpose of the present paper was therefore to study the serial changes of serum soluble markers released from T helper 1 (Th1) and 2 (Th2) and their correlations with treatment responses in chronic hepatitis C patients receiving interferon‐α plus ribavirin for 24 weeks.

Methods:  Serum markers (soluble CD26 and CD30 levels) of T helper cells were quantified before and 6 months after combination therapy in 33 chronic hepatitis C patients and in 20 healthy controls.

Results:  Compared to healthy controls, chronic hepatitis C patients had significantly lower serum soluble CD26 levels before (140.4 ± 63.9 ng/mL vs 200.6 ± 60.3 ng/mL, P < 0.0001) and after (115.9 ± 32.9 ng/mL vs 200.6 ± 60.3 ng/mL, P < 0.0001) combination therapy. The level was even lower in those with non‐sustained virologic response (non‐SVR; 139.0 ± 50.9 ng/mL vs 117.7 ± 40.3 ng/mL, P = 0.039). In contrast, soluble CD30 levels at 6 months after combination therapy were significantly lower in patients with SVR than those with non‐SVR (6.4 ± 3.5 U/mL vs 10.4 ± 5.4 U/mL, P = 0.021).

Conclusion:  Chronic hepatitis C patients have a weak Th1 response as reflected by lower soluble CD26 levels and the levels are even lower in non‐sustained responders. In sharp contrast, downregulation of Th2 response with serial changes of soluble CD30 level is associated with successful treatment of HCV infection.