BOB Ped Surg 2023 - Maria Soledad Jara Valdivia, CIPESUR - Presentation

The immunohistochemical staining CD56 is useful in the diagnosis of biliary atresia. Good morning, we have no conflict of interest. Biliary atresia leads to liver cirrhosis without early treatment. The diagnosis of BA can be challenging as its histopathologic features overlap with those of other pediatric cholestatic liver diseases. The most helpful hallmark of BA on histology is portal fibrosis and bile duct proliferation. However, a similar pattern can be found in other causes of cholestasis such as familiar intrahepatic cholestasis, neonatal hepatitis, and Alagille syndrome among others. During cirrhosis, biliary epithelial structure express immunohistochemical markers of immaturity such as CD56. The study aims to estimate the diagnostic accuracy of CD56 for BA. Regarding the methodology, we have institutional review board approval. This was diagnostic test study including liver biopsies from 2013 to 2019, categorized as group BA, patients with BA, group NC, patients with non-cirrhotic liver disease such as tumors, focal nodular hyperplasia, choledochal cyst, etc. Group C, no BA, patients with cirrhotic pathology other than BA, such as autoimmune hepatitis, neonatal hepatitis, and familial intrahepatic cholestasis among others. Clinical diagnosis was defined as the gold standard, an estimated sample size of 31 patients per group including 20% anticipated loss. Confidence level 95%, a statistical power 80%, um P were patients than 0.05. Liver tissues were stained with CD56 markers, ready to use monoclonal antibody, clone 123 C3 DKO. Two anatomopathologists, blinded to the clinical histological diagnosis, observed and analyzed the presence of CD56 and categorized as CD56 positive or negative each tissue sample. CD56+ was defined as presence greater than 5% in the ductular epithelial cells. Sensitivity, specificity, positive predictive value, negative predictive value, area under the curve and likelihood radius were estimated. Sub analysis for group BA was performed to determine if CD56 stained greater than 5% is the most accurate cutoff for diagnosis. Concerning the results, 639 biopsies were performed between 2013 and 2019. A computer program randomly selected 31 tissue samples for each group with exclusion due to insufficient tissues for CD56 staining, groups were distributed as follows: group BA equals 30 patients, group NC equals 28 patients, group C, no BA equals 31. Of the most important results to highlight, we have that the performance of CD56 plus was higher for BA compared to the other groups, with a sensitivity of 74% versus 16 and 9, a specificity of 87.7 versus 61 and 50. The PPV was 76 versus 18 and 9%, and the NPV was 80 versus 57 and 50. The AUC was 0.81. In a second analysis, we review the biopsies only from the BA group to determine that CD56 value with a cutoff at fewer than 5% cell staining was adequate to be considered positive. For this, the biopsies were separated into marking quantiles. We got that the labeling quantile from 6 to 25% had a higher sensitivity and adequate specificity. Diagnosis of BA can be challenging. Previous authors showed that CD56 immunohistochemical marker might be helpful for the diagnosis of BA. In this randomized blinded study, we determined that the presence of CD56 in more than 5% of the ductular epithelial cells has a sensitivity of 74.2% versus 16.1 and 968 in non-BA groups. The specificity of 87.7% and LHR+ of 6.04 compared to 0.42 and 0.20 in a non BA group to diagnose biliary atresia. In addition, an NPV of 86.2 show that if CD56 is negative, biliary atresia is unlikely. In conclusion, CD56 IHC stain is helpful as a complementary test in liver biopsies to rule out biliary atresia as an etiology for neonates presenting with cholestasis. Thank you all.