BDNF and asthma: Platelets have been shown to migrate actively into the lung and to contribute to functional changes within the airways in allergic airway inflammation.40, 41 Thus, it can be speculated that not only a BDNF overproduction in the airways by leucocytes and epithelia, but also an enhanced deposition of BDNF by platelets might contribute to the development of AHR in asthma.