Franco A M F, Glória J C, Chaves Y O, Ferreira A S, Teles C B G, Balieiro A A S, Neves W L L, Sousa L P de, Costa J D N, Nogueira P A, Mariúba L A M
Programa de Pós-Graduação em Biotecnologia, Universidade Federal do Amazonas, Manaus, AM, Brasil.
Instituto Leônidas e Maria Deane, Fundação Oswaldo Cruz, Manaus, AM, Brasil.
Braz J Med Biol Res. 2025 Feb 3;58:e14114. doi: 10.1590/1414-431X2024e14114. eCollection 2025.
Malaria is a parasitic disease of great relevance in global public health. The development of new sensitive and specific diagnostic high-throughput methods remains a challenge in the eradication of this disease. In this study, we developed a flow cytometry test using latex microbeads and polyclonal antibodies obtained from rabbits and mice for the detection of the P. vivax lactate dehydrogenase (PvLDH) antigen. We processed 50 samples from Brazilian patients diagnosed with malaria caused by P. vivax and 40 samples from healthy individuals. The assay presented sensitivity of 64%, specificity of 97%, a positive predictive value of 97%, and a negative predictive value of 57% when analyzed using the fluorescent labeling method. Using the mean fluorescence intensity (MFI) analysis method, the sensitivity was 53%, specificity was 89%, the positive predictive value was 95%, and the negative predictive value was 33%. In both methods of analysis, we observed significant statistical differences between the analyzed groups (P-value <0.0001). A high correlation (0.60) between the two methods and a low correlation between PvLDH concentration and parasite density was found. The test was able to detect the PvLDH protein with high specificity, but its sensitivity should be improved. More promising results were observed when the samples were analyzed according to the percentage of fluorescent labeling. Improvement of this assay would enable its application as a serological test for the detection of asymptomatic patients and for the validation of rapid diagnostic tests.
疟疾是一种在全球公共卫生领域极具相关性的寄生虫病。开发新的灵敏且特异的诊断高通量方法在根除这种疾病方面仍然是一项挑战。在本研究中，我们开发了一种流式细胞术检测方法，使用从兔子和小鼠获得的乳胶微珠和多克隆抗体来检测间日疟原虫乳酸脱氢酶（PvLDH）抗原。我们处理了50份来自巴西被诊断为间日疟原虫引起的疟疾患者的样本以及40份来自健康个体的样本。当使用荧光标记法分析时，该检测方法的灵敏度为64%，特异性为97%，阳性预测值为97%，阴性预测值为57%。使用平均荧光强度（MFI）分析方法时，灵敏度为53%，特异性为89%，阳性预测值为95%，阴性预测值为33%。在两种分析方法中，我们观察到分析组之间存在显著的统计学差异（P值<0.0001）。发现两种方法之间具有高度相关性（0.60），且PvLDH浓度与寄生虫密度之间相关性较低。该检测能够以高特异性检测PvLDH蛋白，但其灵敏度有待提高。当根据荧光标记百分比分析样本时观察到了更有前景的结果。改进该检测方法将使其能够作为一种血清学检测方法用于检测无症状患者以及验证快速诊断检测。
