Recombinant human nerve growth factor, molecular model. Nerve growth factor (NGF) is involved primarily in the growth, as well as the maintenance, proliferation, and survival of sympathetic and sensory neurons, as they undergo apoptosis in its absence. Recombinant human nerve growth factor (rhNGF) is regarded as a promising therapy for neurodegeneration of the central and peripheral nervous systems as well as for several other pathological conditions involving the immune system.