EVALUATION OF IGE LEVELS AGAINST CULICOIDES NUBECULOSUS ALLERGENS IN BELGIAN WARM BLOODHORSES

摘要

Insect bite hypersensitivity (IBH) represents an IgE-mediated type I (immediate and late-phase) and/or sometimes also type IV (delayed) hypersensitivity to salivary antigens from Culicoides species (Langner et al., 2008; Hellberg et al. 2006) and possibly other insects. Affected horses often develop severe skin lesions due to self-mutilation in an attempt to alleviate the itch (Scott et al, 2003). The lesions are mainly seen during summer season on mane and tail although lesions on face, ears, withers, rump, chest and belly can also occur (Fadok and Greiner, 1990). Severely affected horses are not suitable for riding or showing purposes because of the extreme discomfort and disfigurement. The IBH etiology is multifactorial in origin and involves environmental and genetic factors. Until now, there is no curative treatment available. There are clear indications that the susceptibility for IBH is heritable (Schurink et al., 2011). A molecular genetic analysis may lead to the identification of mutations associated with IBH susceptibility. One approach could be to compare DNA of IBH-affected horses (cases) with DNA of IBH-unaffected horses (controls). The level of discrimination between the selected control and case group affects the chances to identify molecular marker associated with IBH. At present, the diagnosis of IBH is based on the combination of the history, a physical examination and ruling out other conditions causing pruritus, but misdiagnosis can occur. A better definition of the phe-notypes, i.e. presence or absence of allergen-specific IgE in the IBH cases and controls should allow to improve the genetic analysis. Culicoides nubecu-losus salivary gland allergens associated with IBH have recently been cloned, characterized and produced as recombinant allergens (Schaffartzik et al. 2010, 2011) and a cross-reactive allergen from Simulium vittatum (Simvl) and Culicoides nubeculosus has been identified. The aim of our study is to evaluate IgE levels against recombinant salivary gland allergens from C. Nubeculosus in Warmblood horses living in Belgium (BWH). Until now, the allergen specific IgE ELISA was only performed on Icelandic horses (Schaffartzik et al, 2011).