Assessment of plasma anti-elastin antibodies for use as a diagnostic aid for chronic progressive lymphoedema in Belgian Draught Horses

• Published in: Veterinary immunology and immunopathology 2015-01, Vol.163 (1-2), p.16-22
• Main Authors: De Keyser, K., Berth, M., Christensen, N., Willaert, S., Janssens, S., Ducatelle, R., Goddeeris, B.M., De Cock, H.E.V., Buys, N.
• Format: Article
• Language: English
• Subjects: Age Factors; Animals; Anti-elastin Ab; Antibodies - blood; Antibodies - immunology; Belgian Draught Horse; Chronic progressive lymphoedema; Elastin - immunology; ELISA; Enzyme-Linked Immunosorbent Assay - veterinary; Female; Horse Diseases - blood; Horse Diseases - diagnosis; Horse Diseases - immunology; Horses - blood; Horses - immunology; Lymphedema - blood; Lymphedema - diagnosis; Lymphedema - immunology; Lymphedema - veterinary; Male; Pregnancy; Reproducibility of Results; Sensitivity and Specificity
• ISSN: 0165-2427; 1873-2534
• DOI: 10.1016/j.vetimm.2014.11.004

Diagnosis of chronic progressive lymphoedema (CPL) in draught horses, including the Belgian Draught Horse, is mainly based on clinical evaluation of typical lower limb lesions. A deficient perilymphatic elastic support, caused by a pathological elastin degradation in skin and subcutis, has been suggested as a contributing factor for CPL. Elastin degradation products induce the generation of anti-elastin Ab (AEAb), detectable in horse serum by ELISA. For a clinically healthy group of draught horses, a significantly lower average AEAb-level than 3 clinically affected groups (mild, moderate and severe symptoms) was demonstrated previously. To improve CPL-diagnosis, we evaluated the AEAb-ELISA as an in vitro diagnostic aid in individual horses. Test reproducibility was assessed, performing assays independently in 2 laboratories on a total of 345 horses. Possible factors associated with AEAb-levels (age, gender, pregnancy, test lab and date of blood collection) were analyzed using a mixed statistical model. Results were reproducible in both laboratories. AEAb-levels in moderately and severely affected horses were significantly higher than in healthy horses. Nevertheless, this was only demonstrated in barren mares, and, there was a very large overlap between the clinical groups. Consequently, even when a high AEAb cut-off was handled to obtain a reasonable specificity of 90%, a very low sensitivity (21%) of AEAb for CPL-diagnosis was obtained. Results on the present sample demonstrate that the described ELISA procedure is of no use as a diagnostic test for CPL in individual horses.