Wilkerson M J, Davis E, Shuman W, Harkin K, Cox J, Rush B
Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan 66506-5606, USA.
J Vet Intern Med. 2000 Mar-Apr;14(2):190-6. doi: 10.1892/0891-6640(2000)014<0190:iaihad>2.3.co;2.
Classes of antibody bound to erythrocytes were determined using direct immunofluorescence (DIF) flow cytometry in 3 horses and 12 dogs with immune-mediated hemolytic anemia (IMHA). Background levels of antibody binding were determined in samples from 12 horses and 12 dogs that were free of clinical disease. The range of nonspecific binding of a fluorescein isothiocyanate (FITC)-conjugated goat anti-equine immunoglobulin G (IgG) was 19.9-36.7%, but was eliminated by the use of the F(ab')2 fragment of FITC-conjugated goat anti-equine IgG. Background binding by other class-specific antibodies to equine and canine erythrocytes was negligible. The DIF results were compared to the direct antiglobulin (Coombs') test in 5 horses and 20 dogs with anemia. The former assay was more sensitive in dogs with IMHA than was the Coombs' test (100% versus 58%). In contrast, the Coombs' test had better specificity than the DIF assay (100% versus 87.5%, respectively). Using clinical parameters or response to therapy as the comparison, the positive and negative predictive values for the DIF test were 92% and 100% compared to the values of the Coombs' test of 100% and 62%. The DIF assay detected low levels of cells bound with antibody (<30%) in 5 dogs that were Coombs' test-negative. For both species, performance of the DIF test was independent of the prozone effect. Five dogs with IMHA had IgG and IgM on erythrocytes, 5 had IgG, and 2 had IgM. Three horses had surface-bound IgG, including a horse with suspected penicillin-induced IMHA, a foal with neonatal isoerythrolysis, and a foal with clostridial septicemia. The DIF method was valuable in monitoring the response to therapy in the foal with neonatal isoerythrolysis.
采用直接免疫荧光（DIF）流式细胞术，对3匹马和12只患有免疫介导性溶血性贫血（IMHA）的犬测定了与红细胞结合的抗体类别。在12匹和12只无临床疾病的马和犬的样本中测定了抗体结合的背景水平。异硫氰酸荧光素（FITC）标记的山羊抗马免疫球蛋白G（IgG）的非特异性结合范围为19.9% - 36.7%，但通过使用FITC标记的山羊抗马IgG的F(ab')2片段可消除。其他类别特异性抗体与马和犬红细胞的背景结合可忽略不计。将5匹马和20只贫血犬的DIF结果与直接抗球蛋白（库姆斯）试验进行了比较。在前一种检测中，IMHA犬比库姆斯试验更敏感（100%对58%）。相反，库姆斯试验比DIF检测具有更好的特异性（分别为100%对87.5%）。以临床参数或治疗反应作为比较，DIF试验的阳性和阴性预测值分别为92%和100%，而库姆斯试验的值为100%和62%。DIF检测在5只库姆斯试验阴性的犬中检测到低水平的与抗体结合的细胞（<30%）。对于这两个物种，DIF试验的性能与前带效应无关。5只患有IMHA的犬红细胞上有IgG和IgM，5只有IgG，2只有IgM。3匹马有表面结合的IgG，包括一匹疑似青霉素诱导的IMHA马、一匹患有新生儿同种免疫溶血病的驹和一匹患有梭菌败血症的驹。DIF方法对于监测患有新生儿同种免疫溶血病的驹的治疗反应很有价值。
