Leukocyte compartments in the nasal secretion medium

Nasal secretions are known to play a role in respiratory tract and host defense. Besides the mucociliary transport and biochemical properties of the mucus, we hypothesize the role of a secretory leukocyte compartment. We designed a time-series study to count leukocytes in baseline, physically- and pharmacologically-induced secretions. Twenty-three healthy volunteers and 29 patients participated in the study. In healthy subjects, secretion weights significantly increased from 24 +/- 5 mg (mean +/- SEM) at baseline to 35 +/- 6 mg and 115 +/- 12 mg, respectively, in physically and methacholine-induced secretions (p < 0.05). The leukocyte count did not change between baseline (14,445 +/- 5,010) and physically induced secretions (13,396 +/- 6,8401), but significantly increased after methacholine (28,140 +/- 11,411; p = 0.02). Leukocyte differential counts showed, moreover, an increase of lymphocytes in the methacholine-induced compartment. In patients, secretion weights significantly increased from 70 +/- 12 mg at baseline to 117 +/- 22 mg and 223 +/- 28 mg, respectively. The leukocyte count significantly increased between baseline (172,109 +/- 95,890) and physically induced secretions (410,503 +/- 318,224; p = 0.02), but decreased after methacholine (112,774 +/- 54,860). These data argue for the existence of a secretory leukocyte compartment, with a subcompartment of surface and an intraglandular subcompartment of reserve, the kinetics of which are different in patients and control subjects.