Am. J. Respir. Crit. Care Med., Vol 153, No. 4, Apr 1996, 1222-1229.
Inflammatory cellular influx follows capsaicin nasal challenge
G Philip, AM Sanico and A Togias
Department of Medicine, Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland, USA.
Capsaicin is a specific activator of sensory nerve endings. In rodents,
mucosal application of capsaicin causes cells to infiltrate the tissue. To
examine whether inflammatory-cell influx follows sensory-nerve activation
in human airways, we delivered capsaicin (200 microM) nasal spray into the
nares of 20 subjects (10 with allergic rhinitis and 10 normal), and
measured the total leukocyte content of nasal lavage fluid obtained from 10
min to 4 h after the capsaicin challenge. Vehicle spray (1% EtOH in 0.9%
saline) served as a control. Capsaicin challenge caused significant
increases from prechallenge leukocyte counts at 10 min (p<0.03), 30 min
(p<0.01), and 4 h (p<0.03) after challenge, but not at 1 h after
challenge (p = 0.68). Vehicle challenge did not increase leukocyte counts.
Differential counts (performed on the 13 of 20 subjects from whom adequate
specimens for differential counts were obtained) showed that neutrophils,
eosinophils, and mononuclear cells increased at 10 min, 30 min, and 4 h
(all p < 0.04), but not at 1 h after capsaicin challenge. Comparing the
rhinitic to the normal subjects, we found no significant differences in the
cellular response to capsaicin. These data support a nonspecific
inflammatory effect of sensory nerve activation in the human nose.
Consequently, this work provides evidence that neurogenic inflammation can
be induced in the human airway in vivo.
