Differential up-regulation of neurotrophin receptors and functional activity of neurotrophins on peripheral blood eosinophils of patients with allergic rhinitis, atopic dermatitis and nonatopic subjects.
BACKGROUND
Recent studies suggest that neurotrophins have a pivotal role in neuroimmune interactions. Indeed, in contrast to nonatopic subjects (NA), neurotrophins have been shown to be increased in atopic diseases such as allergic rhinitis (AR) and atopic dermatitis (AD).


OBJECTIVE
The aim of the study was to assess the functional role of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin (NT)-3 and -4 and the expression of pan-neurotrophin receptor (p75(NTR)) and tyrosine kinase (trk)A, -B and -C on peripheral blood eosinophils in AR, AD and NA.


METHODS
Peripheral blood eosinophils of patients with AR, AD and NA were purified by CD16 negative selection (purity>98%). Neurotrophin receptor expression was analysed by FACS analysis. Apoptosis test (FACS analysis) and chemotactic index (modified Boyden chamber assay) were assessed after stimulation with BDNF, NT-3/-4 and NGF.


RESULTS
The expression of trkA-C and p75(NTR) was significantly higher in AD>AR>NA (P<0.05-0.001). Apoptosis was significantly inhibited by BDNF, NGF, NT-3 in AD (P<0.05-0.001), by NT-3/-4 and NGF in AR (P<0.05-0.01) and by NT-3 (P<0.05-0.01) in NA eosinophils. Chemotaxis was significantly induced by BDNF and NT-3/4 (P<0.01-0.001) in AD peripheral blood eosinophils.


CONCLUSIONS
Neurotrophin receptor expression and neurotrophin functional activity was greatest in AD>AR>NA. AD eosinophils are pre-activated and may therefore better respond to neurotrophins. With this study, we provide new pathophysiologic insights into atopic diseases with a functional role of neurotrophins in peripheral blood eosinophils in AD and AR.
Raap
U
U
Department of Dermatology and Allergology, Hannover Medical School, Hannover, Germany. raap.ulrike@mh-hannover.de
Deneka
N
N
Bruder
M
M
Kapp
A
A
Wedi
B
B
D019208:Brain-Derived Neurotrophic Factor / Q000502:physiology; D002633:Chemotaxis; D003876:Dermatitis, Atopic / Q000276:immunology / Q000378:metabolism*; D004804:Eosinophils / Q000502:physiology*; D006801:Humans; D020932:Nerve Growth Factor / Q000502:physiology; D009414:Nerve Growth Factors / Q000502:physiology*; D020933:Neurotrophin 3 / Q000502:physiology; D020800:Receptor, Nerve Growth Factor / Q000378:metabolism; D020917:Receptor, trkA / Q000378:metabolism; D020813:Receptor, trkB / Q000378:metabolism; D020812:Receptor, trkC / Q000378:metabolism; D017475:Receptors, Nerve Growth Factor / Q000096:biosynthesis*; D012221:Rhinitis, Allergic, Perennial / Q000276:immunology / Q000378:metabolism*; D015854:Up-Regulation
D019208:Brain-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D020933:Neurotrophin 3; D020800:Receptor, Nerve Growth Factor; D017475:Receptors, Nerve Growth Factor; D020932:Nerve Growth Factor; D020917:Receptor, trkA; D020813:Receptor, trkB; D020812:Receptor, trkC; C073922:neurotrophin 4