Limited Utility of Plasma M30 in Discriminating Non-Alcoholic Steatohepatitis from Steatosis – A Comparison with Routine Biochemical Markers

Abstract

IntroductionThe utility of Cytokeratin-18 fragment, namely CK18Asp396 (M30), for the diagnosis of non-alcoholic steatohepatitis (NASH) is currently uncertain. We aimed to provide further data in this area among multi-ethnic Asian subjects with NAFLD.Materials and MethodsThe accuracy of M30 for detecting NASH was compared with serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma glutamyl transpeptidase (GGT) levels in consecutive adult subjects with biopsy-proven non-alcoholic fatty liver disease (NAFLD).ResultsData for 93 NAFLD subjects (mean age 51.0±11.1 years old and 51.6% males) and 20 healthy controls (mean age 50.2±16.4 years old and 33.3% males) were analyzed. There were 39 NASH subjects (41.9%) and 54 non-NASH subjects (58.1%) among the NAFLD subjects. Plasma M30 (349 U/L vs. 162 U/L), and serum ALT (70 IU/L vs. 26 IU/L), AST (41 IU/L vs. 20 IU/L) and GGT (75 IU/L vs. 33 IU/L) were significantly higher in NAFLD subjects than in healthy controls. Serum ALT (86 IU/L vs. 61 IU/L), AST (58 IU/L vs. 34 IU/L) and GGT (97 IU/L vs. 56 IU/L) were significantly higher in NASH subjects compared to non-NASH subjects, but no significant difference was observed with plasma M30 (435 U/L vs. 331 U/L). The accuracy of plasma M30, and serum ALT, AST and GGT was good for predicting NAFLD (AUROC 0.91, 0.95, 0.87 and 0.85, respectively) but less so for NASH (AUROC 0.59, 0.64, 0.75 and 0.68, respectively). Serum ALT and AST, but not plasma M30 showed a significant trend with increasing grades of ballooning and lobular inflammation.ConclusionThe utility of M30 in the detection of NASH in clinical practice appears limited, in comparison to routine biochemical markers.

Poor Inter-test Reliability Between CK18 Kits as a Biomarker of NASH

“…Previous studies, using the same Test 2 for the diagnosis of NASH, achieved sensitivity of 56% – 77% and specificity of 63% – 92%, demonstrating a wide range despite using the same kit(24)(23)(22). Using the optimal serum CK18 cut-offs for our cohort (356.18U/L for NASH and 395.97U/L for advanced fibrosis diagnosis), the accuracy of Test 2 are 64.6% and 71.8%, respectively, resulting in the misclassification of 35.4% and 28.2% patients for NASH and advanced fibrosis, respectively.…”

“…Although the multicenter validation study published by Feldstein et al showed higher AUROC for prediction of NASH (0.83), most of recent studies demonstrated lower values ranging from 0.53 to 0.63 for NASH and 0.53 to 0.68 for fibrosis prediction(24) , (23) , (27). One possible explanation for this contradictory results is the different percentages of subjects with NASH among studies- 49% of our cohort had NASH, compared to just 19% of the previous validation cohort.…”

“…Although previous studies(1) , (22) showed that CK18 is a clinical relevant biomarker and has sufficient diagnostic accuracy in detection or exclusion of NASH, recent publications showed poorer test performance of CK18 with a low sensitivity as a diagnostic test for NASH(23) , (24). The differences in test performance are seen between studies using the same ELISA kits and between studies that use different kits.…”

Emerging new standard for non-invasive assessment of liver disease mortality in non-alcoholic fatty liver disease

“…For example, in a study on 173 biopsy-proven NAFLD patients, serum ALT level was not associated with histological severity, and normal serum ALT level was observed even in patients with NASH and significant fibrosis (10). In a study at our centre, serum AST level was found to have only fair accuracy in discriminating NASH from non-NASH among biopsy-proven NAFLD patients (9). Further analysis revealed that elevated serum AST level, especially when over twice the upper limit of normal, had excellent predictive value for the presence of NASH.…”

“…NASH is the more severe form of NAFLD that can lead to fibrosis and cirrhosis, and has been associated with increased liver disease mortality (3). NAFLD comprises of several histological components (8), and these markers may be variably expressed with different severity of each of these histological components, not to mention with different individuals, so much so that having a marker that could accurately characterize an individual patient using a pre-determined threshold is not always possible (9). For example, in a study on 173 biopsy-proven NAFLD patients, serum ALT level was not associated with histological severity, and normal serum ALT level was observed even in patients with NASH and significant fibrosis (10).…”