Platelets and hypersensitivity.
Platelets are anucleated blood cells not exclusively committed to hemostasis. They participate in inflammation, tissue repair, the immune response and hypersensitivity. In this review, the role of platelets in hypersensitivity is summarized. In order to understand the profound implications of these cells, the authors introduce the involvement of platelets in inflammation and immune reactions. Both the pathophysiology and the biology of the interaction of platelets with other cells are then summarized. These interactions justify the actual knowledge about the possibilities for the involvement of platelets in clinical states of hypersensitivity. Furthermore, the participation of platelets in allergy is supported by biological and clinical evidence, including in vitro studies of platelet activity in hypersensitivity states, the demonstration of platelet killing and the response to parasite contact, as well as animal studies in which the response to immune aggression is dependent on platelet reactivity. However, the need for more complete and developed clinical studies is clearly stressed, as several therapeutic approaches can already be proposed for a better control of these processes.