US scientists hope a discovery about a potentially deadly disease may eventually help to reduce the need for liver transplants in children.
Biliary atresia leads to up to half of children's liver transplants
Biliary atresia accounts for up to 50% of children who undergo liver transplantation.
Cincinnati Children's Hospital researchers used state-of-the-art technology to determine the genetic underpinning of the disease.
They hope their work, published in The Lancet, will lead to new treatments.
Biliary atresia occurs in infants and usually becomes evident two to eight weeks after birth. Its cause has been unknown.
Symptoms include unexplained jaundice, dark urine, clay-coloured stools and weight loss.
The disease destroys bile ducts in the liver, trapping bile, rapidly causing damage to liver cells and severe scarring.
Although a surgical procedure is successful in many infants, three of every four children who have biliary atresia need a liver transplant before the age of 20.
The Cincinnati team obtained biopsies of livers of 14 infants with biliary atresia.
Using gene chip technology, they found that the development of the disease seems to be linked to the secretion of proteins called cytokines, which trigger inflammation.
The researchers discovered that in the early phases of biliary atresia, genes that trigger inflammation are activated, and genes that produce chemicals to fight infection are suppressed.
The team also compared the samples with biopsies taken from six infants with another liver condition called cholestasis.
This is the build up of the digestive juice bile in the liver caused by a blockage to the bile ducts.
The researchers found that while two-thirds of infants with biliary atresia produced a cytokine called gamma-interferon, the protein was not found in any of the samples of infants with cholestasis.
Lead reseacher Dr Jorge Bezerra said: "This means that infants with biliary atresia may be very prone to drive an inflammatory response against themselves.
"These inflammatory cells see the biliary system as a foreign target."
Dr Bezerra is now working to understand the molecular process more fully and determine the exact pathways causing the disease.
He hopes to develop a new therapy to target disease progression.
Professor Deirdre Kelly, head of the liver unit at Birmingham Children's Hospital, told BBC News Online the research was interesting - but it would be wrong to raise hopes too high.
"It is far too early to make dramatic statements about new therapy or a reduction in liver transplants," she said.
"Dr Bezzera has carried out very important work using new genetic technology to answer why some infants develop biliary atresia.
"He has identified an increase in the genes that regulate inflammatory cells and proteins called cytokines in the liver.
"But although he has found a difference in the immune profile in biliary atresia compared to other diseases, this could be a reaction to the disease and not the cause of the disease.
"Further work in both animal models and affected infants may lead to a better understanding of the disease."