Increased production of the immunological substance sCD14 after HCV infection
1 September 2016
The intestinal flora is important for maintaining an immunological balance. This is mainly due to leakage of bacterial products through the intestinal wall rendering them visible to the immune system. This process, called microbial translocation induces a response of the immune system by producing a substance called sCD14.
HIV infection increases the permeability of the intestinal wall, resulting in more leakage of bacterial products, causing an incresas in sCD14 in the blood. A chronic infection and prolonged elevation of bacterial translocation may most likely increases the risk of prolonged overstimulation of the immune system. This may cause exhaustion of the immune system.
During chronic HCV infection similar elevated concentrations of sCD14 are found in the blood. However, HCV infection also disrupts the hepatic function, and therefore it is not clear whether the increase is caused by intestinal damage, or by a reduced function of the liver. Unlike humans, the liver function of chimpanzees chronically infected with HCV is not impaired. Therefore chimpanzees are ideally suited to study this.
In the past, research at the BPRC was performed with HIV or HCV-infected chimpanzees. Materials from these studies, such as blood cells and serum were stored. This archieved material was used to investigated further investigate whether bacterial translocation can occur in chimpanzees. In frozen blood samples from HIV-infected chimpanzees they found a significantly increased levels of sCD14. Analogous to humans infected with HIV, this was caused by an increased permeability of the intestinal wall.
Similarly increased concentration of sCD14 were found in the blood of HCV infected chimpanzees but in these animals this was not accompanied by increased permeability of the intestine. This indicates HCV infection induces the production of sCD14. The researchers found indications that this also occurs in humans.
The results of this research, published in the Journal of General Virology (https://www.ncbi.nlm.nih.gov/pubmed/27534537) contribute to a better understanding of the disease process of HCV infection.