Increased Plasma Levels of Nerve Growth Factor in Vernal ... - IOVS

Increased Plasma Levels of Nerve Growth Factor in Vernal Keratoconjunctivitis and Relationship to Conjunctival Mast Cells Alessandro Lambiase*X Stefano Bonini,* Sergio Bonini,^ Alessandra Micera,X Laura Magrini,\ Luisq Bracci-Laudiero,X and Luigi Aloe%

Purpose. To evaluate the nerve growth factor (NGF) plasma concentration in patients with vernal keratoconjunctivitis and to correlate it with the histopathology and immunopathology of the disease. Methods. An iminunocnzymatic assay was performed to measure NGF plasma levels in patjents with vernal keraloconjunctivitis and in healthy matched controls. A competitive radioimmunoassay was used to delect eosinophil cationic protein (ECP) and total andspecific immunoglobulin E (IgE) serum levels. Histologic evaluation was performed in larsal and bulbar conjunctival biopsies. Results. Plasma levels of NGF were significantly higher (P < 0.001) in patients with vernal keratoconjunctivitis (mean = 8224.47 ± 7802.53 pg/ml; median = 121 pg/ml) than in controls (mean = 51.68 ± 5.94 pg/ml; median = 42.5 pg/ml). Conjunctival tissue showed a significant increase of mast cells, eosinophils, and lymphocytes in vernal keratoconjunctivitis. A significant correlation was observed between plasma levels of NGF and the number of mast cells in the tarsal conjunctiva (Gc = 0.81; P < 0.005) and bulbar conjunctiva (Cc = 0.77; P < 0.01) of patients" with vernal keratoconjunctivitis. No correlation was found between NGF plasma levels and total IgE serum levels in patients with vernal keratoconjunctivitis; NGF plasma levels were inversely related to the number of circulating eosinophils (Cc = —0.61; P < 0.05) and to the increased serum levels of ECP (Cc = -0.71; P < 0.02). Conclusions. These data represent the first reported evidence of increased NGF plasma levels in an allergic human disease and suggest a possible relationship between this neurotrophic polypeptide and inflammatory cells in vernal keratoconjunctivitis. Invest Ophthalmol Vis Sci. 1995;36:2127-2132.

JNcrve growth factor (NGF) is the best-characterized member of the neurotrophin family essential for the survival, differentiation, and function of peripheral sympathetic and sensory neurons and basal forebrain cholinergic neurons in the central nervous system.1 Its biologic action is not restricted to cells of neuronal origin but extends to cells of the immune system.2 For example, in vivo administration of NGF to neonatal rats increases the size and number of mast cells in horn the *l)ef>artment of Ophtlialmology, Unnitnsitf of Home Toy Vngntn, the \Chan ofClmual Immunology and Allergology, Setond University of NnpU">, and the \ln\titnte 0/ Sentobiology, Consiglio Nnzionnh' delle Hi