[Cell Activation Markers in Rhinitis and Rhinosinusitis. 1: Eosinophilic Cationic Protein (ECP)]

Background: The quantitative analysis of the migration and activation of inflammatory cells is standard in current diagnosis of inflammatory diseases of the nasal mucosa. Histological and cytological examinations are mostly used for this purpose. Development and validation of assays for specific marker proteins of the different cell populations make similar analyses possible from nasal secretion samples. Myeloperoxidase (MPO) or Elastase are important markers for neutrophil granulocytes as is Tryptase for mast cells, Lysozyme for macrophages/monocytes and Eosinophil Cationic Protein (ECP). Eosinophil Neurotoxin/Eosinophil Protein X (EDN/EPX) or Major Basic Protein (MBP) for eosinophil granulocytes.

Methods: We performed a prospective study on healthy volunteers and patients with different inflammatory nasal and paranasal sinus diseases and analysed such cell activation markers in nasal secretions. In the healthy volunteers, 183 nasal secretion samples were obtained. A total of 515 samples were obtained in patients with the diagnosis: chronic sinusitis (n = 49), allergic rhinitis to perennial allergens (n = 94), chronic sinusitis with additional allergic rhinitis to perennial allergens (n = 36), nasal polyps (n = 28), allergic rhinitis to seasonal allergens extraseasonally (n = 131), and allergic rhinitis to seasonal allergens during the pollen season (n = 177).

Results: In part I of this paper we describe the results for the Eosinophil Cationic Protein (ECP). In all patients with active inflammatory reactions significantly higher ECP levels than in the controls were found. Moreover, ECP levels differed between the diseases investigated.

Conclusions: ECP nasal secretion level seem to be a valuable marker for the assessment of nasal eosinophilic inflammation and might become an adjunct to current diagnostic measures.