Ochoa-Grullón J, Orte C, Rodríguez de la Peña A, Guevara-Hoyer K, Cordero Torres G, Fernández-Arquero M, Serrano-García I, Recio M J, Pérez de Diego R, Sánchez-Ramón S
Department of Immunology, IML and IdSSC, Hospital Clínico San Carlos, Madrid, Spain.
Department of Immunology, Ophthalmology and ENT, School of Medicine, Complutense University School of Medicine, Madrid, Spain.
MethodsX. 2020 May 29;7:100936. doi: 10.1016/j.mex.2020.100936. eCollection 2020.
Assessment of specific antibody (Ab) production to polysaccharide antigens is clinically relevant, identifying patients at risk for infection by encapsulated bacteria and thus enabling a more rigorous selection of patients that can benefit of immunoglobulin replacement therapy. Classically, the gold-standard test is the measurement of antibody production to pure polysaccharide pneumococcal (PPV) immunization. Several factors, including introduction of conjugate vaccination schedule, serotyping analysis, high baseline Ab levels, have hindered the evaluation of polysaccharide antigens. This is even more difficult in secondary immunodeficiencies (SID), where patients can show secondary responses despite lack of primary antibody responses and present with recurrent or severe infections. Assessment of specific Ab production to pure S polysaccharide (TV) immunization has been proposed as a complementary test to PPV, given its low seroprevalence. To set the optimal cut-off value for PPV and TV response in SID, we tested different biostatistical methodologies, including ROC analysis, Youden index, Union index and Closest-topleft in a cohort of 42 SID patients and 24 healthy controls. The statistically chosen cut-offs value pre-post TV Ab ratio was ≥5, (sensitivity of 90%, specificity of 100%) and a postvaccination TV concentration of 28.5 U/mL (sensitivity of 90%, specificity of 95%), showing relevant clinical correlate.
评估针对多糖抗原的特异性抗体（Ab）产生情况具有临床相关性，可识别有被包膜细菌感染风险的患者，从而能够更严格地筛选可从免疫球蛋白替代疗法中获益的患者。传统上，金标准检测是测量对纯多糖肺炎球菌（PPV）免疫接种的抗体产生情况。包括引入联合疫苗接种程序、血清分型分析、高基线Ab水平在内的多种因素，都阻碍了对多糖抗原的评估。在继发性免疫缺陷（SID）患者中，这一评估更为困难，因为这些患者尽管缺乏初始抗体反应，但仍可表现出二次反应，并出现反复或严重感染。鉴于纯S多糖（TV）的血清阳性率较低，已有人提出评估对纯TV免疫接种的特异性Ab产生情况，作为对PPV的补充检测。为了确定SID患者中PPV和TV反应的最佳临界值，我们在42例SID患者和24例健康对照组成的队列中测试了不同的生物统计学方法，包括ROC分析、约登指数、联合指数和最接近左上角法。经统计学选择的TV Ab前后比值临界值为≥5（敏感性90%，特异性100%），接种疫苗后TV浓度为28.5 U/mL（敏感性90%，特异性95%），显示出相关的临床关联。
