The diagnostic role of cytokeratin 8/18 immunohistochemical marker for lean nafld

Background and Aims: Non-alcoholic fatty liver disease (NAFLD) is one of the leading causes of chronic liver diseases. NAFLD spectrum begins from simple steatosis to nonalcoholic steatohepatitis (NASH), progressive fibrosis, cirrhosis, and even HCC. Although most NAFLD patients are overweight and obese, 30% are lean. We analyzed lean and nonlean NAFLD patients' liver biopsies for cytokeratin 8/18 immunohistochemical staining differences. Matherial and Methods: Thirty biopsy-proven NAFLD patients (15 patients with BMI ≤ 25 kg/m2 , 15 patients with BMI > 25 kg/m2 ) were included in the study. Demographic, biochemical, and histologic features of the patients were recorded. Biopsy specimens from our archive were re-stained with cytokeratin 8/18 marker and were re-evaluated by a single expert hepatopathologist according to Brunt's classification, NASH-CRN scoring system, and FLIP algorithm. Results: The presence of pathological granular staining with cytokeratin 8/18 marker in hepatocytes positively correlated with ballooning degeneration (r=0.461, p=0.027), the grade of lobular inflammation according to the FLIP algorithm (r=0.461, p=0.027), the grade of lobular inflammation according to the NAFLD activity score (r=0.545, p=0.007), presence of portal inflammation (r=0.525, p=0.010), age (r=0.534, p=0.009), gender (r=0.464, p=0.026), serum glucose value (r=0.537, p=0.008), direct bilirubin (r=0.523, p=0.022) and HbA1c (r=0.758, p=0.029) levels, and negatively correlated with hemoglobin (r=-0.473, p=0.030) and hematocrit (r=-0.437, p=0.047) levels. There was no significant difference in the presence or staining pattern of cytokeratin 8/18 marker between the two groups. In the lean NAFLD group, liver damage was milder, serum triglyceride levels were lower (p=0.003) and ALT values were higher (p=0.031) compared to the non-lean group. Conclusions: Although the presence of cytokeratin 8/18 immune marker staining has no role in the differential diagnosis of lean and non-lean NAFLD, the presence of granular staining may be an indicator of progression. Keywords: Lean NAFLD, cytokeratin 8/18 immunohistochemical marker, biopsy