Langner Kathrin F A, Darpel Karin E, Drolet Barbara S, Fischer Angelika, Hampel Stefan, Heselhaus Julia E, Mellor Philip S, Mertens Peter P C, Leibold Wolfgang
University of Veterinary Medicine, Bischofsholer Damm 15, 30173 Hannover, Germany.
Vet Immunol Immunopathol. 2008 Mar 15;122(1-2):126-37. doi: 10.1016/j.vetimm.2007.11.001. Epub 2007 Nov 9.
The objective of this study was to compare and analyze three common diagnostic methods for summer eczema (SE) in horses, an allergic dermatitis caused by bites of Culicoides spp. Nine horses with a medical history of SE and nine control animals were intradermally challenged with whole body extracts (WBE) and the saliva of a native (C. nubeculosus) and exotic (C. sonorensis) Culicoides species. Blood and serum samples of the horses were examined for basophil reactivity by a histamine release test (HRT) and for Culicoides-specific serum immunoglobulin E (IgE) and G (IgG) by enzyme-linked immunosorbent assay (ELISA). The results of intradermal testing (IDT) at 30min (immediate reactivity) and 4h (late-phase reactivity) post challenge with most insect preparations revealed significant differences between horses with and without SE. Overall, the HRT showed the most accurate results with a sensitivity of 1.00 for all Culicoides preparations and specificities of 0.78 (WBE) and 1.00 (saliva). By contrast, delayed reactions of the IDT (24h), and levels of Culicoides-specific IgE and IgG in the native serum showed little or no distinction between allergic and non-allergic horses. However, the use of purified serum IgE and IgG indicated the possibility for elevated titers of insect-specific serum immunoglobulins in horses with SE. The IDT and HRT did not reveal obvious differences in onset and intensity of positive reactions for the native verses exotic Culicoides species, whereas the ELISA showed slightly higher numbers of positive reactions for serum IgG with the indigenous species. Saliva, as compared to WBE, was found to have improved sensitivity and/or specificity for the HRT and for the late-phase immune reactions as measured by the IDT. Overall, the results indicate that allergy tests utilizing effector cells (mast cells, basophils) are more accurate in diagnosing SE in horses than serological analysis by ELISA.
本研究的目的是比较和分析马夏季湿疹（SE）的三种常见诊断方法，SE是一种由库蠓叮咬引起的过敏性皮炎。对9匹有SE病史的马和9只对照动物进行皮内注射全身提取物（WBE）以及本地库蠓（C. nubeculosus）和外来库蠓（C. sonorensis）的唾液进行激发试验。通过组胺释放试验（HRT）检测马的血液和血清样本中的嗜碱性粒细胞反应性，并通过酶联免疫吸附测定（ELISA）检测库蠓特异性血清免疫球蛋白E（IgE）和G（IgG）。在大多数昆虫制剂激发后30分钟（即时反应性）和4小时（迟发性反应性）进行皮内试验（IDT）的结果显示，有SE和无SE的马之间存在显著差异。总体而言，HRT显示出最准确的结果，对所有库蠓制剂的敏感性为1.00，对WBE的特异性为0.78，对唾液的特异性为1.00。相比之下，IDT的延迟反应（24小时）以及本地血清中库蠓特异性IgE和IgG的水平在过敏性和非过敏性马之间几乎没有区别。然而，使用纯化的血清IgE和IgG表明，患有SE的马中昆虫特异性血清免疫球蛋白的滴度可能升高。IDT和HRT未显示本地库蠓与外来库蠓物种在阳性反应的发作和强度上有明显差异，而ELISA显示本地物种血清IgG的阳性反应数量略多。与WBE相比，唾液在HRT和通过IDT测量的迟发性免疫反应中具有更高的敏感性和/或特异性。总体而言，结果表明利用效应细胞（肥大细胞、嗜碱性粒细胞）的过敏试验在诊断马的SE方面比ELISA血清学分析更准确。
