By suppressing the immune system, hepatitis C may be able to keep the body from attacking a newly transplanted organ.

It turns out there’s a silver lining to having hepatitis C (HCV), an infection that can badly damage the liver. According to a new study in Science Translational Medicine, the hepatitis C virus can suppress the immune response that causes the body to reject transplanted organs as foreign invaders.

Usually, transplant patients with viral infections are not included in clinical trials because their infection is thought to hamper the success of the transplant.

Felix Bohne, Ph.D., a researcher at the Helmholtz Zentrum München center for environmental health research in Germany, studied 34 patients with HCV who had recently had a liver transplant. Bohne showed that the patients could stop taking immunosuppressive drugs to prevent rejection.

His team found that the mechanism viruses typically use to avoid being detected by the immune system actually creates an environment that encourages transplant tolerance. In effect, the virus acts like an immunosuppressive medication. However, the same results have not been seen in animal studies of HCV.

The researchers say they are not sure if this protective effect occurs in transplanted organs in other parts of the body, but the results explain more about how chronic viral infections affect transplant patients. The findings could also change the way clinical trials are designed in the future.

“The main option now is to find out exactly how the virus can favor the immunologic tolerance and try to mimic this, in order to get a therapy which can induce transplant tolerance without the need for the virus,” Bohne said.

Learn More: How Does Hepatitis C Affect the Body? »