Changes of gut bacteria and immune parameters in liver transplant recipients

Liver transplantation is one of the most effective therapeutic options for patients with end-stage liver diseases, and gut microbiota is actively involved in potential infections in pretransplant and posttransplant patients. However, the diversity of gut microbiota and its relationship with the immune parameter of liver transplantation recipients are not well understood.

We collected fresh feces and blood samples from 190 participants in China from November 2004 to May 2008, including 28 healthy volunteers, 51 cirrhotic patients and 111 liver-transplanted patients. Six interesting gut bacteria, plasma endotoxin, serum cytokines (i.e., tumor necrosis factor alpha and interleukin-6) and fecal secretory IgA (SIgA) were investigated by real-time quantitative PCR, chromogenic limulus amoebocyte assay, sandwich-type enzyme-linked immunosorbent assay and radioimmunoassay, respectively.

All Eubacteria, Bifidobacterium spp., Faecalibacterium prausnitzii and Lactobacillus spp. were significantly lower in the liver transplantation recipients while Enterobacteriaceae and Enterococcus spp. were significantly higher (P<0.05). Except for Enterococcus spp., other bacteria showed a tendency to restore to normal level along with the time after liver transplantation. Plasma endotoxin, interleukin-6 and fecal SIgA in cirrhotic patients increased significantly, but not in liver transplantation recipients. Plasma endotoxin and interleukin-6 were negatively correlated with all Eubacteria and the Bacteroides-Prevotella group, while tumor necrosis factor alpha was not significantly correlated with these six gut bacteria in cirrhotic patients.

Our study demonstrates that abundant gut bacteria were altered significantly in both cirrhotic and liver transplantation patients, while plasma endotoxin and interleukin-6 increased remarkably in cirrhotic patients, showing significant correlations with gut microbiota. Interestingly, our data show a tendency for these gut bacteria to restore to normal levels in liver transplantation recipients.