Jones R R, Pusey C, Schifferli J, Johnston N A
Br J Vener Dis. 1983 Feb;59(1):33-6. doi: 10.1136/sti.59.1.33.
Analysis of serum from a patient with cutaneous leukocytoclastic vasculitis showed a mixed cryoglobulin with a monoclonal IgM kappa-antiglobulin component (6.5 mg/ml), strong rheumatoid factor activity (latex titre 1/5000), and positive serological tests for syphilis (fluorescent treponemal antibody-absorbed and Treponema pallidum haemagglutination assay). After removal of antiglobulin activity by immunoabsorption with heat-aggregated gammaglobulin all serological test results for treponemal infection became negative. Serological tests for syphilis and rheumatoid factor on the supernatant from whole serum (minus cryoglobulin) remained positive though at a lower titre (latex 1/1250). Cryoglobulin isolated from whole serum retained rheumatoid and TPHA reactivity but was negative in the FTA-ABS test. The IgM and IgG cryoglobulin components purified by gel filtration on Sepharose showed no antitreponemal reactivity even when tested individually. Reducing the concentration of cryoglobulin to 1.5 mg/ml by plasma exchange converted the test results for syphilis to doubtful-positive or negative. These results indicated that high concentrations of antiglobulin activity may be associated with falsely positive specific antitreponemal test results and that this phenomenon depends on the concentration of cryoglobulin in the test sample.
对一名皮肤白细胞破碎性血管炎患者的血清分析显示，其冷球蛋白为混合型，含有单克隆IgM κ抗球蛋白成分（6.5毫克/毫升），类风湿因子活性较强（乳胶凝集效价1/5000），梅毒血清学检测呈阳性（荧光密螺旋体抗体吸收试验和梅毒螺旋体血凝试验）。用热聚集γ球蛋白进行免疫吸附去除抗球蛋白活性后，所有梅毒螺旋体感染的血清学检测结果均变为阴性。全血清（不含冷球蛋白）上清液的梅毒血清学检测和类风湿因子检测仍为阳性，但效价较低（乳胶凝集1/1250）。从全血清中分离出的冷球蛋白保留了类风湿因子和梅毒螺旋体血凝试验的反应性，但在荧光密螺旋体抗体吸收试验中呈阴性。通过琼脂糖凝胶过滤纯化的IgM和IgG冷球蛋白成分，即使单独检测也未显示抗梅毒螺旋体反应性。通过血浆置换将冷球蛋白浓度降至1.5毫克/毫升，梅毒检测结果变为可疑阳性或阴性。这些结果表明，高浓度的抗球蛋白活性可能与梅毒螺旋体特异性检测结果假阳性有关，且这种现象取决于检测样本中冷球蛋白的浓度。
