433 SERUM ADIPOKINES CONCENTRATION IN CHILDREN WITH NON-ALCOHOLIC FATTY LIVER DISEASE

Background and Aims: Hepatic cyst infection is a serious complication in autosomal dominant polycystic kidney disease (ADPKD) patients, with a potentially unfavourable outcome if diagnosis and treatment are delayed. The diagnosis of hepatic cyst infection in ADPKD is difficult because symptoms and imaging techniques can be non-specific. Furthermore, there is no specific blood marker for this infection. We hypothesized that Carbohydrate antigen 19.9 (CA19.9), secreted by the biliary epithelium lining the cysts, is overproduced in case of cyst infection. Methods: CA19.9 was measured in the serum of three kidney transplant ADPKD patients who presented with hepatic cyst infection, and in the cystic fluid of 2 of them. CA19.9 was also measured in the serum of 19 consecutive ADPKD and 22 non-ADPKD renal transplant recipients. CA19.9 immunostaining was done in 5 polycystic livers of ADPKD patients and compared with control normal livers. Results: Three ADPKD patients were diagnosed with hepatic cyst infection based on clinical grounds, biological inflammation, and positron emission tomography scan. All had at that time markedly elevated serum CA19.9 levels (963, 2975, and 601U/ml respectively; N< 35U/ml). Two patients required cystic fluid drainage. CA19.9 level was extremely elevated in the cystic fluid (728,200 and 124,200U/ml respectively). With clinical improvement, a striking decrease in serum CA19.9 level was observed in all patients. Serum CA19.9 from 19 consecutive asymptomatic ADPKD patients with liver cysts was significantly higher than in controls (median: 29.55 vs. 10.3U/ml, p< 0.001). Bilirubin level was normal in all patients of both groups. Immunostaining for CA19.9 revealed strong staining in biliary tree epithelia and cysts of human polycystic livers, significantly more intense than in normal livers. Conclusions: CA19.9 is synthesized by the biliary cystic epithelium and can be elevated in ADPKD patients with liver cysts. A marked increase in serum CA19.9 level is observed with liver cyst infection. Our data strongly suggest that the serum level of CA19.9 can be a diagnostic tool for hepatic cyst infection, contributing to early diagnosis and appropriate management. Measurement of baseline serum CA19.9 level in ADPKD patients could serve as a reference value.