YKL-40

Overview

YKL-40, also known as chitinase-3-like-1 protein (CHI3L1), is a secreted glycoprotein produced by macrophages, neutrophils, and other cells during inflammation. It lacks chitinase activity but binds chitin and regulates cell proliferation, tissue remodeling, and Th2 immune responses. Elevated serum levels indicate inflammation, tissue injury, or remodeling in conditions such as asthma, COPD, liver fibrosis, and certain cancers; low levels have no established clinical significance. YKL-40 serves as a biomarker for disease activity, prognosis, and response to therapy in inflammatory and fibrotic disorders, though it lacks disease specificity.

Clinical Use Cases

  • Prognostication in chronic obstructive pulmonary disease (COPD) exacerbation risk.
  • Monitoring liver fibrosis progression in chronic hepatitis and NAFLD.
  • Assessing asthma severity and airway remodeling.
  • Cancer prognosis (e.g., colorectal, breast, lung) and metastasis risk.
  • Cardiovascular disease risk stratification in stable angina.
  • Research marker for rheumatoid arthritis and osteoarthritis activity.

Specimen Types

  • Serum.
  • Plasma (EDTA or citrate).
  • Synovial fluid (joint diseases).
  • Bronchoalveolar lavage fluid (lung diseases).

Measurement Methods

  • Enzyme-linked immunosorbent assay (ELISA).
  • Electrochemiluminescence immunoassay.
  • Latex-enhanced immunoturbidimetric assay.
  • Multiplex bead-based immunoassays.

Test Preparation and Influencing Factors

  • No fasting required.
  • Acute inflammation, infection, or trauma elevates levels.
  • Age, smoking, and obesity increase baseline concentrations.
  • Renal impairment reduces clearance, elevating serum levels.
  • Sample hemolysis interferes with immunoassays.
  • Diurnal variation minimal; stable at room temperature for 24 hours.

Synonyms

  • Chitinase-3-like-1 protein.
  • CHI3L1.
  • Human cartilage glycoprotein-39 (HC-gp39).
  • YKL-40 protein.

Further Reading