Neuronal markers in allergic rhinitis: expression and correlation with sensory testing.
BACKGROUND
Although the role of immunoglobulin E-mediated hypersensitivity reactions in allergic rhinitis is well known, the relative contribution of sensory nerves to the symptoms of rhinitis is uncertain. This study looked at the level of specific neuronal markers including the nerve marker protein gene product 9.5 (PGP 9.5), sensory and autonomic neuropeptides, the capsaicin/heat receptor TRPV1, and nerve growth factor (NGF) in patients with allergic rhinitis and controls and their correlation with nasal sensitivity.


METHODS
Forty patients (23 controls, 17 rhinitis) having nasal surgery were recruited. Nasal sensitivity was tested using graded monofilaments. Inferior turbinate biopsies were collected and studied using immunohistology, with measurement of nerve fibers by direct observation or computerized image analysis.


RESULTS
Nerve fibers (PGP 9.5) in the epithelium, subepithelium, and glandular/vascular regions were significantly increased in allergic rhinitis (P=.037, <.01, and .04, respectively), as were subepithelial and glandular/vascular fibers immunoreactive for neuropeptide substance P (P=.04 subepithelium; .02 glandular/vascular) and neuropeptide tyrosine (P<.01 glandular/vascular), markers for sensory and sympathetic nerves, respectively. TRPV1 epithelial fiber counts were higher in rhinitis, but this was not statistically significant. Epithelial NGF immunoreactivity (% area) was significantly increased in rhinitis (P=.027). Nasal sensitivity was correlated significantly with PGP 9.5 subepithelial innervation (control touch P=.023, irritation P=.046; rhinitis touch P=.042, irritation P=.043). A correlation was also observed between epithelial NGF and subepithelial PGP 9.5 innervation, which included all subjects (P=.044).


CONCLUSIONS
The increased number and specific phenotypical changes of sensory nerves may play a role in nasal hypersensitivity and provide new targets for the treatment of rhinitis.
Peripheral Neuropathy Unit, Hammersmith Hospital, Faculty of Medicine, Imperial College London, London, UK.
Stephen
S
O'Hanlon
Paul
P
Facer
Karen D
KD
Simpson
Guri
G
Sandhu
Hesham A
HA
Saleh
Praveen
P
Anand
D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000294:innervation* / Q000378:metabolism / Q000473:pathology; D009300:Nasal Septum / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D009412:Nerve Fibers / Q000378:metabolism; D009414:Nerve Growth Factors / Q000235:genetics* / Q000378:metabolism*; D009475:Neurons, Afferent / Q000378:metabolism*; D011300:Preoperative Care; D012221:Rhinitis, Allergic, Perennial / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D012225:Rhinoplasty; D013373:Substance P / Q000378:metabolism; D050916:TRPV Cation Channels / Q000235:genetics* / Q000378:metabolism*
D009414:Nerve Growth Factors; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; D013373:Substance P; D007073:Immunoglobulin E