New Strategies for Prevention and Treatment of Insect Bite Hypersensitivity in Horses

Purpose of Review Treatment of equine insect bite hypersensitivity (IBH) needs to be improved. Allergen-specific immunotherapy (ASIT), the only curative treatment of allergy, currently has only a limited efficacy for treatment of IBH. This review highlights the latest findings in prophylactic and therapeutic strategies. Recent Findings Prophylactic vaccination against IBH using recombinant Culicoides allergen has been developed in unexposed Icelandic horses and is ready to be tested. Therapeutic virus-like particle (VLP)-based vaccines targeting equine interleukin- (IL-) 5 or IL-31 improved clinical signs of IBH by induction of anti-cytokine antibodies thus reducing eosinophil counts or allergic pruritus, respectively. First studies for development of ASIT using pure r-Culicoides allergens have yielded promising results and need now to be tested in clinical studies for both prevention and treatment of IBH. Therapeutic vaccines inducing neutralizing antibodies against IL-5 or IL-31 will be valuable future treatments for reduction of clinical signs of IBH.