Protocol Liver Biopsies in Pediatric Liver Transplant Recipients

Abstract

Background: The usefulness of protocol graft biopsies in liver transplant (LT) recipients remains controversial. Many centers perform them, considering they are the only tool for diagnosing and monitoring fibrosis (Fb) and chronic hepatitis (CH) because biochemical parameters do not exactly correlate with histopathological changes. We started protocol biopsies for pediatric LT recipients of our center in 2010. Aim: To describe histological findings in healthy LT pediatric recipients of our hospital. Material and methods: We retrospectively analyzed clinical charts and 34 liver biopsies of 23 LT pediatric recipients with normal liver functional tests (LFTs) who received transplants between January 2003 and December 2011 in our center and had protocol biopsies between January 2010 and December 2011. Patients with abnormal clinical features and/or abnormal LFTs were excluded (mild transaminases elevation up to 1.5-2 folds above normal values were tolerated). Results: 23 patients, 8 males (34.8%) and 15 females (65.2%) were analyzed. Median age at transplant was 24 months (from 5 months to 15 years). Etiologies were 10 biliary atresia (43.5%), 9 acute liver failure (39.2%), 2 autoimmune hepatitis (8.7%), 1 Alagille syndrome (4.3%) and 1 Tyrosinemia type 1 (4.3%). 13 patients received living donor LT (56.5%) and 10 were transplanted with cadaveric donor (43.5%). All patients received standard immunosuppression with steroids and Tacrolimus. First liver biopsy was performed around 6 months post transplant in 10 patients, 1 year pos transplant in 6 patients and between 3 and 7 years post transplant in 7 patients because by the time we started protocol controls they were at that moment post transplant. In 9 patients we performed second liver biopsy around 1 year after the first one. There were no complications with the biopsies. Histological results were normal or nearly normal in 8 specimens (34.7%); CH with moderate Fb in 4 (17.4%); CH without Fb in 3 (13%); ductular reaction in 3 (13%). Less common features were cholestatic hepatitis, sinusoidal congestion and acute cellular rejection; one patient showed recurrent autoimmune hepatitis one year after transplant. We guided immunosuppressant therapy with histological results. Conclusion: CH and Fb were frequent in our LT pediatric patients and we detected them with protocol biopsies. Besides, one patient showed recurrent autoimmune hepatitis and we could manage immunosuppression before clinical or biochemical symptoms appeared. We consider protocol liver biopsy as an important tool for evaluation of graft function. We do not know the cause of certain histological abnormalities, but protocol biopsies allow us to adjust immunosuppressant and monitor outcome of LT pediatric recipients.