Acute phase reactants have been implicated for their involvement as proinflammatory molecules in various inflammatory diseases. However, little is known regarding their role in the allergic airway disease. The aim of the present study was to examine the blood concentrations of three acute-phase proteins, namely C-reactive protein (CRP), serum amyloid A (SAA) and fibrinogen in patients with allergic rhinitis and asthma. Three study groups include: non-smoker allergic rhinitis (n = 50), non-smoker asthma (n = 20), and non-allergic, non-smoker healthy control subjects (n = 20). Patients who have had recent upper or lower respiratory tract infection and trauma, any rheumatological illnesses, malignancy or obesity were excluded. Blood samples were obtained from all the patients and control subjects and were analyzed for serum CRP, SAA and plasma fibrinogen. The mean CRP and fibrinogen values in the rhinitis and asthma groups were not significantly different when compared to the control group. However, the mean SAA levels of both groups were found to be significantly higher than those of the control group (p = 0.002 for rhinitis, p = 0.02 for asthma). There was no significant correlation between the FEV1 values and the levels of the serum markers. This study demonstrates that acute phase reactant SAA rises in patients with allergic rhinitis and patients with asthma. We therefore suggest that SAA may have a role in the inflammatory airway disease. (C) 2004 Tohoku University Medical Press.