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.
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 pediatric 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.
05/05/05
Reference
H M Evans, A Deirdre, P Kelly, P J McKiernan, and S G Hübscher. Progressive Histological
Damage in Liver Allografts Following Pediatric Liver Transplantation. Hepatology
43(5): 1109-1117.
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