INTRODUCTION: Nerve growth factor (NGF) is a neurotrophin that exerts an important role in the development and functions of the central and peripheral nervous system, as it was originally discovered for its properties of simulating growth and differentiation of neurons; however, it was recently documented that several immune cells, such as mast cells, lymphocytes, and eosinophils, produce, store, and release NGF. Neurotrophins, including NGF, are constitutively expressed by resident lung cells and produced in increasing quantities by immune cells that invade the airways under inflammatory conditions. Furthermore, NGF appears as a promoter of allergic airway inflammation by increasing eosinophil and lymphocyte recruitment into the lungs. Neurotrophin receptors are expressed on several immune cells, including mast cells, T cells, B cells, and macrophages.
OBJECTIVE: The objective of this study was to clarify the role of NGF in allergic and inflammatory lung diseases.
METHODS: Our study was conducted of 90 children who attended the outpatient pediatric clinic or were admitted to the inpatient pediatric department of Elminia University Hospital. They were classified into 3 groups as follows: group 1, 35 children with asthma during the acute attack; group 2, 35 children with severe inflammatory lung disease and bronchopneumonia; group 3, 20 seemingly healthy children who were age and gender matched to the children with disease. For all children, the following were done: careful history taking, thorough clinical examination, chest radiograph, complete blood count, erythrocyte sedimentation rate, and reverse-transcriptase polymerase chain reaction (RT-PCR) to detect NGF receptor mRNA expression on purified eosinophils that were obtained from peripheral blood.
RESULTS: We found only 3 patients who had asthma and had positive NGF receptors on isolated eosinophils from the peripheral blood by RT-PCR; however, all studied patients with bronchopneumonia had negative results. Moreover, there was a statistically significant difference between patients with positive and negative results for NGF receptors on isolated eosinophils by RT-PCR regarding age, the frequency of recurrence of asthma attacks, and positive history of other atopic diseases such as allergic dermatitis and allergic rhinitis; however, there was no statistically significant difference between patients with positive and negative results regarding gender, type of feeding, or family history.
CONCLUSIONS: There is a strong association between NGF receptors on isolated eosinophils and the severity of allergic lung diseases and bronchial asthma.
Submitted by Basma Abdelmoez
- Copyright © 2008 by the American Academy of Pediatrics