Perkins G A, Nydam D V, Flaminio M J B F, Ainsworth D M
Department of Clinical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
J Vet Intern Med. 2003 May-Jun;17(3):337-42. doi: 10.1111/j.1939-1676.2003.tb02458.x.
The purposes of this study were to (1) prospectively establish serum IgM and IgG concentrations in normal, fit, adult horses over time and (2) determine the accuracy of serum IgM concentrations for diagnosing lymphoma. Serial IgM and IgG concentrations were measured with a radial immunodiffusion assay in 25 regularly exercised horses at 6-week intervals. Horses had serum IgM concentrations ranging from 50 to 242 mg/dL over 5 months, with 20% of horses having IgM < or = 60 mg/dL. The normal range for IgM in fit horses should be considered 103 +/- 40 mg/dL and a cut-point for an IgM deficiency, < or = 23 mg/dL. IgG concentrations ranged from 1,372 to 3,032 mg/dL. Retrospectively, medical records of adult horses (n = 103) admitted to the Cornell University Hospital for Animals for which serum IgM was measured were examined. Horses were categorized as "lymphoma negative" (n = 34) or "lymphoma positive" (n = 18). The sensitivity and specificity of a serum IgM concentration (< or = 60 mg/dL) for detecting equine lymphoma was 50 and 35%, respectively. At the new cut-point (< or = 23 mg/dL), the sensitivity was low at 28% and the specificity improved to 88%. The negative predictive values at various population prevalences indicate that a horse with a high serum IgM (> 23 mg/dL) is unlikely to have lymphoma, whereas the positive predictive value (70%) does not allow for reliable determination of lymphoma in a horse with serum IgM < or = 23 mg/dL. Therefore, serum IgM concentrations should not be used as a screening test for equine lymphoma.
（1）前瞻性地确定正常、健康成年马随时间变化的血清IgM和IgG浓度；（2）确定血清IgM浓度对诊断淋巴瘤的准确性。采用放射免疫扩散法，对25匹定期运动的马每隔6周测量一次系列IgM和IgG浓度。在5个月的时间里，马的血清IgM浓度范围为50至242mg/dL，其中20%的马IgM≤60mg/dL。健康马的IgM正常范围应视为103±40mg/dL，IgM缺乏的切点为≤23mg/dL。IgG浓度范围为1372至3032mg/dL。回顾性地检查了康奈尔大学动物医院收治的成年马（n=103）的病历，这些马均检测了血清IgM。马被分为“淋巴瘤阴性”（n=34）或“淋巴瘤阳性”（n=18）。血清IgM浓度（≤60mg/dL）检测马淋巴瘤的敏感性和特异性分别为50%和35%。在新的切点（≤23mg/dL）时，敏感性较低，为28%，特异性提高到88%。不同群体患病率下的阴性预测值表明，血清IgM高（>23mg/dL）的马不太可能患淋巴瘤，而阳性预测值（70%）不能可靠地确定血清IgM≤23mg/dL的马是否患有淋巴瘤。因此，血清IgM浓度不应作为马淋巴瘤的筛查试验。
