Serum-soluble Fas levels as a marker to distinguish allergic and nonallergic rhinitis

Abstract

the volunteers who had no sensitization as determined by 7 kinds of RASTs and skin tests. They had no subjective symptoms and no histories of allergic, nasal, or collagen disease. Serum sFas levels in patients with allergic or vasomotor rhinitis were measured by a sandwich ELISA (Medical & Biological Laboratories Co, Nagoya, Japan) and were compared with those in healthy individuals as negative controls and patients with SLE as positive controls. The results were statistically analyzed by the Mann-Whitney U test. RESULTS As shown in Fig 1, the serum sFas levels in patients with allergic rhinitis (0.55 ± 0.35 ng/mL) during the pollen season were less than one third of those in healthy individuals (1.57 ± 0.43 ng/mL). The serum sFas levels in more than 95% of the patients with allergic rhinitis were less than 1 ng/mL. Moreover, serum sFas levels in patients with allergic rhinitis (0.45 ± 0.28 ng/mL) out of season (ie, 1 month after the season) remained significantly lower (P < .0001) than those of healthy individuals. There were no differences in serum sFas levels between patients with vasomotor rhinitis (1.50 ± 0.38 ng/mL) and healthy individuals. The serum sFas levels in all patients with vasomotor rhinitis were greater than 1 ng/mL. As previously reported, levels in patients with SLE (2.55 ± 0.97 ng/mL) were significantly higher (P < .002) than those found in healthy individuals. 3 The magnitude of sFas in patients with SLE and healthy individuals is comparable to the levels reported by Knipping et al,4 although it is more than an order of magnitude lower than the levels reported by Cheng et al. 3 DISCUSSION In this study we demonstrate that the levels of serum sFas in patients with allergic rhinitis were less than 1 ng/mL as opposed to greater than 1 ng/mL in patients with vasomotor rhinitis. These results suggest that the level of serum sFas could be one of the markers used to distinguish allergic rhinitis from nonallergic (vasomotor) rhinitis. The serum sFas level should be a marker to identify allergic subjects rather than active allergic inflammation because serum sFas levels in allergic subjects out of season remained low. Fas is a cell surface molecule that delivers a signal for inducing apoptosis after stimulation with anti-Fas antibody or Fas-ligand. sFas, which is produced by alternative mRNA splicing, antagonizes anti-Fas antibody‐ or Fas ligand‐induced Fas-mediated killing in a dosedependent manner.3,5 Recently, a number of serum sFas