Characterization of the immune cell landscape of patients with NAFLD.

Multiple factors are involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD), but the exact immunological mechanisms that cause inflammation and fibrosis of the liver remain enigmatic. In this current study, cellular samples of a cohort of NAFLD patients (peripheral blood mononuclear cells (PBMC): n = 27, liver samples: n = 15) and healthy individuals (PBMC: n = 26, liver samples: n = 3) were analyzed using 16-color flow cytometry, and the frequency and phenotype of 23 immune cell subtypes was assessed. PBMC of NAFLD patients showed decreased frequencies of total CD3+, CD8+ T cells, CD56dim NK cells and MAIT cells, but elevated frequencies of CD4+ T cells and Th2 cells compared to healthy controls. Intrahepatic lymphocytes (IHL) of NAFLD patients showed decreased frequencies of total T cells, total CD8+ T cells, Vd2+γδ T cells, and CD56bright NK cells, but elevated frequencies of Vδ2-γδ T cells and CD56dim NK cells compared to healthy controls. The activating receptor NKG2D was significantly less frequently expressed among iNKT cells, total NK cells and CD56dim NK cells of PBMC of NAFLD patients compared to healthy controls. More strikingly, hepatic fibrosis as measured by fibroscan elastography negatively correlated with the intrahepatic frequency of total NK cells (r2 = 0,3737, p = 0,02). Hepatic steatosis as measured by controlled attenuation parameter (CAP) value negatively correlated with the frequency of circulating NKG2D+ iNKT cells (r2 = 0,3365, p = 0,0047). Our data provide an overview of the circulating and intrahepatic immune cell composition of NAFLD patients, and point towards a potential role of NK cells and iNKT cells for the regulation of hepatic fibrosis and steatosis in NAFLD.

[Combination of NAFLD Fibrosis Score and liver stiffness measurement for identification of moderate fibrosis stages (II & III) in non-alcoholic fatty liver disease]. / Kombination von NAFLD Fibrosis Score und transienter Elastografie zur Identifikation mittelgradiger Fibrosestadien (II/III) bei nicht-alkoholischer Fettlebererkrankung.

INTRODUCTION: Non-alcoholic fatty liver disease (NAFLD) has become one of the most frequent causes of chronic liver disease. Currently, therapeutic options for NAFLD patients are limited, but new pharmacologic agents are being investigated in the course of clinical trials. Because most of these studies are focusing on patients with fibrosis stages II and III (according to Kleiner), non-invasive identification of patients with intermediate fibrosis stages (II and III) is of increasing interest. AIMS: Evaluation of NAFLD Fibrosis Score (NFS) and liver stiffness measurement (LSM) for prediction of fibrosis stages II/III. METHODS: Patients with histologically confirmed NAFLD diagnosis were included in the study. All patients underwent a clinical and laboratory examination as well as a LSM prior to liver biopsy. Predictive value of NFS and LSM with respect to identification of fibrosis stages II/III was assessed. RESULTS: 134 NAFLD patients were included and analyzed. Median age was 53 (IQR 36 - 60) years, 55 patients (41 %) were female. 82 % of our patients were overweight/obese with typical aspects of metabolic syndrome. 84 patients (66 %) had liver fibrosis, 42 (50 %) advanced fibrosis. LSM and NFS correlated with fibrosis stage (r = 0.696 and r = 0.685, respectively; p < 0.01 for both). NFS values between -2.0 and + 0.5, and LSM values between 8 and 22kPa were associated with fibrosis stages II/III. If both criteria were met, probability of fibrosis stage II/III was 61 %. If none of the two criteria was met, chance for fibrosis stage II/III was only 6 % (negative predictive value 94 %). CONCLUSION: Combination of LSM and NFS enables identification of patients with significant probability of fibrosis stage II/III. Accordingly, these tests, especially in combination, may be a suitable screening tool for fibrosis stages II/III in NAFLD. The use of these non-invasive methods might also help to avoid unnecessary biopsies.