The (potential) role of apolipoproteins in nasal mucus of allergic rhinitis patients

Abstract

Background: Nasal mucus is the first line defense barrier against various allergens. Proteins are functional molecules in mucus and have different roles especially in immune response. Apolipoproteins are plasma proteins that are mainly involved in lipid metabolism, but also have antiinflammatory properties. Method: Fifty-eight individuals were included in this study. Mean age was 34 years comprising 29 (50%) allergic rhinitis patients and 29 (50%) healthy controls. Mucus was taken using a special suction device with a mucus trap and samples were sent for (LC MS/MS) mass spectrometry. Plasma levels of APO-A1 and APO-B were determinded. Results: Apolipoprotein A-IV, Apolipoprotein B-100 were newly identified in nasal mucus and were exclusively present in allergic rhinitis patients not reaching significance. Apolipoprotein A-1 (mean SC = 19 vs 6) and A-2 (mean SC = 9 vs 1) were significantly more abundant in allergic rhinitis patients than healthy controls (3.2 fold and 9.7 fold respectively). Other significantly more abundant proteins in allergic rhinitis patients were Alpha-2- macroglobulin, Alpha1 antitrypsin and Complement C3.Mean plasma concentration of APO-A1 was 178 mg/dl (SD = 25.6) in healthy controls and 188.8 mg/dl (SD = 41.9) in allergic rhinitis patients (P = 0.36). Mean plasma concentration of APO-B was 84.5 mg/dl (SD = 22.9) in healthy controls and 89.5 mg/dl (SD = 15.9) in allergic rhinitis patients (P = 0.43). Conclusion: Apolipoproteins were found to have antimicrobial activities and antiinflammatory properties. Their presence reflects the inflammatory state and recurring acute inflammationof allergic rhinitis mucosa and mucus. Since their plasma concentrations did not differ between allergic rhinitis patients and controls their abundance in allergic nasal mucus seems to be triggered by local mechanisms and not via plasma exsudation. Their role in chronic inflammatory diseases is not clear yet and will be the target of future functional proteomic analysis.