Expression of interleukin-17 is associated with different immune phases in patients with chronic hepatitis B

Serum interleukin-17 is closely related to inflammatory liver injury after hepatitis B virus (HBV) infection. The objective is to study the expression of interleukin-17 (IL-17) in different immune phases in patients with chronic hepatitis B. Whole venous blood was obtained from normal controls (n = 20) and four patient groups (n = 213): immune tolerance phase (IT, n = 57), immune clearance phase (IC, n = 59), non (low)-replicating phase (LR, n = 44), and reactivation phase (RA, n = 53). We measured IL-17, IL-6, and tumor necrosis factor alpha (TNF-α) levels in serum samples and measured IL-17, IL-6, and TNF-α messenger RNA (mRNA) levels in peripheral blood mononuclear cell (PBMC). Compared to normal controls, IL-17, IL-6, and TNF-α protein levels in serum and mRNA levels in PBMC were significantly higher in the four groups. IL-17 protein levels in serum and mRNA levels in PBMC were positively correlated with alanine aminotransferase (ALT), aspartate aminotransferase (AST), IL-6, and TNF-α. Compared to patients in the IT phase and LR phase, patients in the IC phase exhibited the highest serum IL-17 and PBMC mRNA levels. The IL-17 mRNA levels of patients in RA phase were higher than those in patients in IT phase. IL-17 plays an important part in the various immune phases of chronic hepatitis B (CHB).