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John Wiley & Sons, Inc.
Chronic hepatitis in pediatric liver transplant patients
A new study on the long-term outcome of children undergoing liver transplants
found that chronic hepatitis (CH) was common and that it was not detectible
using standard blood tests. The presence of autoantibodies (antibodies that
attack the body's own tissues) in these patients indicates that although not
fully understood, CH may be related to the immune response.
The results of this study appear in the May 2006 issue of Hepatology, the
official journal of the American Association for the Study of Liver Diseases
(AASLD). Published by John Wiley & Sons, Inc., Hepatology is available online
via Wiley InterScience at http://www.interscience.wiley.com/journal/hepatology.
Children normally undergo liver transplants for diseases that do not recur and
are potentially curable by the procedure. Although their long-term survival
rates are over 80 percent, little is known about tissue changes that occur over
time in these young patients. "An important question within the field of
paediatriac liver transplantation is whether children who have undergone
successful transplantation can expect a normal life expectancy or whether there
will be a gradual decline in liver function and eventual graft loss," the
authors write.
Led by Helen M. Evans of the Birmingham Children's Hospital in Birmingham,
United Kingdom, the study involved children who received liver transplants at
the hospital's Liver Unit between 1983 and 1996. Patients underwent standard
liver function tests, sonograms and liver biopsies at approximately 1, 5 and 10
years following transplant, and autoantibodies were measured at 5 and 10 years.
A total of 113 children had liver biopsies at the one year mark, 135 had
biopsies after 5 years, and 64 underwent biopsies at 10 years.
The results showed that there was a decrease over time in the proportion of
biopsies considered to be normal, with chronic hepatitis being the most common
abnormality (22 percent at 1 year, 43 percent at 5 years, 64 percent at 10
years). While liver function tests at 5 years were not significantly different
in children who had CH, the presence of autoantibodies was significantly higher
at 5 and 10 years in children with CH (72 percent and 80 percent respectively).
In addition, there was a strong association between the presence of CH and the
development of progressive fibrosis (the formation of scar-like tissue). The
authors note that "the finding of increasing fibrosis in children with chronic
hepatitis has not been reported before and has potentially important
implications for long term graft function."
The authors note that transient autoantibody production following transplant
sometimes occurs during episodes of rejection. In addition, late rejection may
be associated with tissue changes that are different to those normally seen in
acute rejection but more closely resemble those seen in chronic viral or
autoimmune hepatitis. "It is therefore possible that some cases of otherwise
unexplained chronic hepatitis in the liver allograft may represent a form of
late cellular rejection," the authors suggest.
The results of the present study indicate that important tissue abnormalities
can be detected in biopsies obtained from children who are clinically well and
have normal liver function tests, the authors state. "Screening for chronic
allograft hepatitis using liver biochemistry is therefore not possible and may
instead require regular measurement of autoantibodies," they conclude.
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Article: "Progressive Histological Damage in Liver Allografts Following
Pediatric Liver Transplantation," Helen M. Evans, Deirdre A. Kelly, Patrick J.
McKiernan, Stefan G. Hübscher, Hepatology; May 2006 (DOI: 10.1002/hep.21152).
http://www.eurekalert.org/pub_releases/2006-05/jws-chi050206.php