Expression of histidine decarboxylase messenger RNA and histamine N-methyltransferase messenger RNA in nasal allergy.
BACKGROUND
Histamine is an important chemical mediator in allergic rhinitis. Histamine is synthesized by L-histidine, catalysed by L-histidine decarboxylase (HDC) and metabolized mainly by histamine N-methyltransferase (HMT). The patients with allergic rhinitis may have altered histamine metabolism in the nasal tissue.


OBJECTIVE
The objective was to compare the expression of HDC mRNA and HMT mRNA in nasal mucosa with normal individuals and patients with allergic rhinitis.


METHODS
We extracted RNA from scrapings of inferior turbinate mucosa of 11 patients with allergic rhinitis and from 11 normal subjects and from surgically dissected inferior turbinate mucosa of 11 patients. HDC, HMT and beta-actin mRNA were amplified by reverse transcription-polymerase chain reaction (RT-PCR).


RESULTS
The mean +/- SD of HDC/beta-actin ratios were 0.58 +/- 0.28 for the scrapings of normal subjects, 0.93 +/- 0.38 for the scrapings of the patients with allergic rhinitis and 1.41 +/- 0.26 for the inferior turbinates of the patients with allergic rhinitis. The mean +/- SD of HMT/beta-actin ratios were 1.66 +/- 0.27 for the scrapings of normal subjects, 0.93 +/- 0.20 for the scrapings of the patients with allergic rhinitis and 0.65 +/- 0.28 for the inferior turbinates of the patients with allergic rhinitis. The differences among the three groups were statistically significant.


CONCLUSIONS
Increased HDC mRNA expression and decreased HMT mRNA expression may be playing some role in the hyperresponsiveness of patients with allergic rhinitis.
Department of Otorhinolaryngology, Mie University School of Medicine, Tsu, Japan.
N
N
Hirata
K
K
Takeuchi
K
K
Ukai
Y
Y
Sakakura
D000199:Actins / Q000235:genetics; D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D015870:Gene Expression; D006637:Histamine N-Methyltransferase / Q000235:genetics*; D006640:Histidine Decarboxylase / Q000235:genetics*; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000473:pathology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics*; D012221:Rhinitis, Allergic, Perennial / Q000235:genetics*
D000199:Actins; D012333:RNA, Messenger; D006637:Histamine N-Methyltransferase; D006640:Histidine Decarboxylase