BDNF and allergic rhinitis: Given the complex crosstalk between cytokines, neuropeptides and neurotrophins in allergic inflammation, it is hypothesized that acupuncture might exert anti-inflammatory actions in allergic rhinitis in three ways: firstly, by down-regulating Th2 and proinflammatory cytokines and up-regulating Th1 cytokines; secondly, by down-regulating proinflammatory neuropeptides (namely SP, VIP, and CGRP) and finally, by downregulating neurotrophins (NGF and BDNF) (see Figure 3).