Eosinophil cationic protein (ECP) in the cerebrospinal fluid

Area of Science:

• Neuroimmunology
• Clinical Chemistry

Background:

• Cerebrospinal fluid (CSF) analysis aids in diagnosing central nervous system (CNS) diseases.
• Eosinophil cationic protein (ECP) is a marker of eosinophil activity.
• Neutrophils and blood-brain barrier (BBB) integrity are also assessed using lactoferrin and albumin.

Observation:

• ECP levels were measured in CSF from 210 patients with diverse neurological conditions.
• Lactoferrin and albumin were concurrently measured to assess neutrophil activity and BBB function.
• A reference group established an upper normal limit for ECP at 1.7 µg/l.

Findings:

• Elevated ECP was observed in 38% of acute cerebrovascular disease patients, significantly more than lactoferrin (7%).
• 67% of CNS infection patients showed raised ECP, with higher levels in bacterial infections (P < 0.001).
• Malignant tumors (67% elevated ECP) showed significantly higher ECP than benign tumors (6%, P = 0.001).
• ECP correlated with lactoferrin and albumin in infectious and tumor groups.
• 25% of multiple sclerosis patients had elevated ECP, similar to lactoferrin levels.

Implications:

• ECP is a sensitive biomarker for eosinophil involvement in CNS diseases like infections and malignant tumors.
• Findings suggest a preferential role for eosinophils over neutrophils in certain neurological conditions.
• Extremely high ECP levels in three patients indicate a potential causal link to brain tissue damage.