Kinetics of phytohemaglutinin-induced IFN-γ and TNF-α expression in peripheral blood mononuclear cells from patients with chronic hepatitis B after liver transplantation

Aim: To study the association between host immunity and hepatitis B virus (HBV) recurrence after liver transplantation. Methods: Peripheral blood mononuclear cells (PBMC) were isolated from 40 patients with hepatitis B and underwent orthotopic liver transplantation (OLT) before and 2, 4, 8 wk after surgery. After being cultured in vitro for 72 h, the levels of INF-γ and TNF-α in culture supernatants were detected with ELISA. At the same time, the quantities of HBV DNA in serum and PBMCs were measured by real time PCR. Results: The levels of INF-γ and TNF-α in PBMC culture supernatants decreased before and 2, 4 wk after surgery in turns (INF-γ 155.52±72.32 ng/L vs 14.76±9.88 ng/L vs 13.22±10.35 ng/L, F = 6.946, P = 0.027<0.05; TNF-α 80.839±46.75 ng/L vs 18.59±17.29 ng/L vs9.758±7.96 ng/L, F = 22.61, P = 0.0001 <0.05). The levels of INF-γ and TNF-α were higher in groups with phytohemagglutinin (PHA) than in those without PHA before surgery. However, the difference disappeared following OLT. Furthermore, INF-γ and TNF-α could not be detected in most patients at wk 4 and none at wk 8 after OLT. The HBV detection rate and virus load in PBMC before and 2, 4 wk after surgery were fluctuated (HBV detected rate: 51.4%, 13.3%, 50% respectively; HBV DNA: 3.55±0.674 log(10) copies/mL vs 3.00±0.329 log(10) copies/mL vs 4.608±1.344 log(10) copies/mL, F= 7.582, P= 0.002<0.05). HBV DNA in serum was 4.48±1.463 log(10) copies/mL before surgery and <10³ copies/mL after OLT except for one with 5.72× 10₆ copies/mL 4 wk after OLT who was diagnosed as HBV recurrence. The levels of INF-γ and TNF-α were lower in patients with a high HBV load than in those with a low HBV load (HBV DNA detected/undetected in PBMCs: IFN-γ 138.08±72.44 ng/L vs 164.24±72.07 ng/L, t = 1.065, P= 0.297>0.05, TNF-α 80.75±47.30 ng/L vs 74.10±49.70 ng/L, t= 0.407, P= 0.686> 0.05; HBV DNA positive/negative: IFN-γ 136.77±70.04 ng/L vs 175.27±71.50 ng/L, t = 1.702, P = 0.097>0.05; TNF-α 75.37±43.02 ng/L vs 81.53±52.46 ng/L, t = 0.402, P = 0.690>0.05). Conclusion: The yielding of INF-γ and TNF-α from PBMCs is inhibited significantly by immunosuppressive agents following OLT with HBV load increased, indicating that the impaired immunity of host is associated with HBV recurrence after OLT.