The Kleiner score is a widely utilized semi-quantitative scoring system for assessing the progression and severity of liver disease, most notably in the context of Non-alcoholic Fatty Liver Disease (NAFLD) and its more severe form, Non-alcoholic Steatohepatitis (NASH). It provides a structured method to evaluate key histological features of liver biopsies.
This scoring system is frequently employed for the semi-quantitative assessment of disease progression in research and clinical settings. It systematically quantifies specific features indicative of active liver injury, alongside a separate score for fibrosis.
Key Components Assessed by the Kleiner Score
The Kleiner score precisely quantifies distinct pathological features observed in liver tissue, categorizing them into active injury and fibrosis.
Features of Active Injury (NASH Activity Score)
The active injury components are crucial for understanding the ongoing damage within the liver. These include:
- Steatosis: This refers to the accumulation of fat (lipids) within liver cells (hepatocytes). The Kleiner score assesses the extent and distribution of fat droplets.
- Inflammation: This component measures the presence and severity of inflammatory cells in the liver, indicating an immune response to cellular damage.
- Ballooning: Hepatocyte ballooning degeneration is a specific type of liver cell injury characterized by swollen and degenerated hepatocytes. It is a hallmark feature often seen in NASH.
These three features — steatosis, inflammation, and ballooning — are combined to form a NASH Activity Score (NAS), which helps determine the level of ongoing liver damage and inflammation.
Fibrosis Score
Separate from the active injury components, the Kleiner score also includes a dedicated assessment of fibrosis. Fibrosis is the scarring of liver tissue that occurs as a response to chronic liver injury. It represents the accumulation of excessive connective tissue and is a critical indicator of disease progression, potentially leading to cirrhosis and liver failure. The fibrosis score helps determine the stage of scarring, ranging from mild to advanced.
Importance and Application
The Kleiner score provides a standardized method for pathologists to assess the severity of NAFLD and NASH from liver biopsy samples. Its applications include:
- Disease Monitoring: Tracking disease progression or regression over time, especially in response to treatment.
- Clinical Trials: Serving as a primary endpoint in clinical trials for new therapeutic agents targeting NAFLD and NASH, enabling researchers to objectively measure treatment efficacy.
- Research: Facilitating consistent pathological evaluation across different studies, thereby enhancing comparability of results.
By quantifying specific histological features, the Kleiner score contributes significantly to the diagnosis, staging, and management of non-alcoholic fatty liver diseases.
Further Reading
For more technical details and research on the Kleiner score, you can explore resources like:
