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Chumworathayee W, Munkongdee T, Buasuwan N, Chaichompoo P, Svasti S. Diagnosis of α-thalassaemia by colorimetric gap loop mediated isothermal amplification. Sci Rep 2023; 13:9612. [PMID: 37311778 DOI: 10.1038/s41598-023-36676-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 06/08/2023] [Indexed: 06/15/2023] Open
Abstract
α-Thalassaemia is an inherited haemoglobin disorder that results from the defective synthesis of α-globin protein. Couples whom both carry the α-thalassaemia 1 gene are at risk of having a foetus with the most severe thalassaemia, Hb Bart's hydrops fetalis, with a risk of maternal mortality. However, haematological parameters alone cannot distinguish between a α-thalassaemia 1 carrier and a homozygous α-thalassaemia 2, in which one α-globin gene has been deleted on each chromosome. A rapid and accurate molecular detection assay is essential for prevention of the disease in populations where α-thalassaemia 1 is common. Multiplex Gap-PCR analysis is widely used for diagnosis of α-thalassaemia. However, the technique requires a thermocycler and post-amplification processing, which limits its application in primary care or in rural areas in developing countries. Loop mediated isothermal amplification (LAMP) amplifies target DNA at a constant temperature and does not require a thermocycler. This study developed a colorimetric Gap-LAMP using malachite green to allow naked eye visualization of two deletional α-thalassaemia 1 commonly found in Asian populations, the Southeast Asian type (--SEA) and the Thai type (--THAI) deletions. The Gap-LAMP was performed on DNA samples from 410 individuals carrying various α-thalassaemia gene defects with 100% concordance with conventional Gap-PCR analysis. This method eliminates post-amplification processing or the use of expensive sophisticated equipment and allows screening large populations for the prevention and control of α-thalassaemia.
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Affiliation(s)
- Worakawee Chumworathayee
- Graduate Program in Molecular Medicine, Faculty of Science, Mahidol University, Bangkok, Thailand
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand
- Division of Biology, Faculty of Science and Technology, Rajamangala University of Technology, Thanyaburi, Pathumthani, Thailand
| | - Thongperm Munkongdee
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand
| | - Nattrika Buasuwan
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand
| | - Pornthip Chaichompoo
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Saovaros Svasti
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand.
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand.
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Yon JLT, Htet NH, Naing C, Tung WS, Aung HH, Mak JW. Loop-mediated isothermal amplification (LAMP) test in the detection of uncomplicated malaria in pregnancy: a meta-analysis of diagnostic accuracy. Malar J 2022; 21:391. [PMID: 36550507 PMCID: PMC9783437 DOI: 10.1186/s12936-022-04419-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Due to relatively low malaria parasitaemia in pregnancy, an appropriate field test that can adequately detect infections in pregnant women presenting with illness or for malaria screening during antenatal care is crucially important. The objective was to evaluate the diagnostic accuracy of loop-mediated isothermal amplification (LAMP) for the detection of uncomplicated malaria in pregnancy. METHODS This was a meta-analysis of diagnostic accuracy. Relevant studies that assessed the diagnostic performance of LAMP for the detection of malaria in pregnancy were searched in health-related electronic databases including PubMed, Ovid, and Google Scholar. The methodological quality of the studies included was evaluated using the QUADAS-2 tool. RESULTS Of the 372 studies identified, eight studies involving 2999 pregnant women in five endemic countries that assessed the accuracy of LAMP were identified. With three types of PCR as reference tests, the pooled sensitivity of LAMP was 91% (95%CI 67-98%) and pooled specificity was 99% (95%CI 83-100%, 4 studies), and the negative likelihood ratio was 9% (2-40%). Caution is needed in the interpretation as there was substantial between-study heterogeneity (I2: 80%), and a low probability that a person without infection is tested negative. With microscopy as a reference, the pooled sensitivity of LAMP was 95% (95%CI 26-100%) and pooled specificity was 100% (95%CI 94-100%, 4 studies). There was a wide range of sensitivity and substantial between-study heterogeneity (I2: 83.5-98.4%). To investigate the source of heterogeneity, a meta-regression analysis was performed with covariates. Of these potential confounding factors, reference test (p: 0.03) and study design (p:0.03) had affected the diagnostic accuracy of LAMP in malaria in pregnancy. Overall, there was a low certainty of the evidence in accuracy estimates. CONCLUSION The findings suggest that LAMP is more sensitive than traditional tests used at facilities, but the utility of detecting and treating these low-density infections is not well understood. Due to the limited number of studies with bias in their methodological quality, variation in the study design, and different types of reference tests further research is likely to change the estimate. Well-conceived large prospective studies with blinding of the index test results are recommenced.
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Affiliation(s)
- Joseph Lee Teck Yon
- grid.411729.80000 0000 8946 5787School of Medicine, International Medical University, Kuala Lumpur, Malaysia ,grid.4305.20000 0004 1936 7988University of Edinburgh, Old College, Edinburgh, EH8 9YL UK
| | - Norah Htet Htet
- grid.411729.80000 0000 8946 5787School of Medicine, International Medical University, Kuala Lumpur, Malaysia
| | - Cho Naing
- grid.1011.10000 0004 0474 1797Division of Tropical Health and Medicine, James Cook University, Townsville, QLD Australia
| | - Wong Siew Tung
- grid.411729.80000 0000 8946 5787School of Medicine, International Medical University, Kuala Lumpur, Malaysia
| | - Htar Htar Aung
- grid.411729.80000 0000 8946 5787School of Medicine, International Medical University, Kuala Lumpur, Malaysia
| | - Joon Wah Mak
- grid.411729.80000 0000 8946 5787Institute of Research, Development and Innovation (IRDI), International Medical University, Kuala Lumpur, Malaysia
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Zhang J, Chen X, Pan M, Qin Y, Zhao H, Yang Q, Li X, Zeng W, Xiang Z, Wu Y, Duan M, Li X, Wang X, Mazier D, Zhang Y, Zhu W, Sun K, Wu Y, Cui L, Huang Y, Yang Z. Application of a low-cost, specific, and sensitive loop-mediated isothermal amplification (LAMP) assay to detect Plasmodium falciparum imported from Africa. Mol Biochem Parasitol 2022; 252:111529. [PMID: 36374724 PMCID: PMC9890345 DOI: 10.1016/j.molbiopara.2022.111529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 08/12/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022]
Abstract
BACKGROUND Chinese citizens traveling abroad bring back imported malaria cases to China. Current malaria diagnostic tests, including microscopy and antigen-detecting rapid tests, cannot reliably detect low-density infections. To complement existing diagnostic methods, we aimed to develop a new loop-mediated isothermal amplification (LAMP) assay to detect and identify Plasmodium falciparum in Chinese travelers returning from Africa. METHODS We developed a miniaturized LAMP assay to amplify the actin I gene of P. falciparum. Each reaction consumed only 25% of the reagents used in a conventional LAMP assay and the same amount of DNA templates used in nested PCR. We evaluated this LAMP assay's performance and compared it to microscopy and a nested PCR assay using 466 suspected malaria cases imported from Africa. We assessed the sensitivity of the new LAMP assay using cultured P. falciparum, clinical samples, and a plasmid construct, allowing unprecedented precision when quantifying the limit of detection. RESULTS The new LAMP assay was highly sensitive and detected two more malaria cases than nested PCR. Compared to nested PCR, the sensitivity and specificity of the novel LAMP assay were 100% [95% confidence interval (CI) 98.5-100%] and 99.1% (95% CI 96.7-99.9%), respectively. When evaluated using serial dilutions of the plasmid construct, the detection limit of the new LAMP was as low as 102 copies/μL, 10-fold lower than PCR. The LAMP assay detected 0.01 parasites/μL of blood (equal to 0.04 parasites/μL of DNA) using cultured P. falciparum and 1-7 parasites/μL of blood (4-28 parasites/μL of DNA) in clinical samples, which is as good as or better than previously reported and commercially licensed assays. CONCLUSION The novel LAMP assay based on the P. falciparum actin I gene was specific, sensitive, and cost-effective, as it consumes 1/4 of the reagents in a typical LAMP reaction.
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Affiliation(s)
- Jiaqi Zhang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China,Zhejiang Provincial Center for Disease Control and Prevention, No.3399 BinSheng Road, Binjiang District, Hangzhou, Zhejiang Province, 310051, China
| | - Xi Chen
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Maohua Pan
- Shanglin County People’s Hospital, Shanglin, Guangxi, 530500, China
| | - Yucheng Qin
- Shanglin County People’s Hospital, Shanglin, Guangxi, 530500, China
| | - Hui Zhao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Qi Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Xinxin Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Weilin Zeng
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Zheng Xiang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Yanrui Wu
- Department of Cell Biology & Genetics, Kunming Medical University, Kunming, Yunnan,China
| | - Mengxi Duan
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Xiaosong Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Xun Wang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Dominique Mazier
- Sorbonne Université, INSERM, CNRS, Centre d’Immunologie et des Maladies Infectieuses, CIMI, Paris, France
| | - Yanmei Zhang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Wenya Zhu
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Kemin Sun
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Yiman Wu
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, MDC84, Tampa, FL 33612, USA
| | - Yaming Huang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China,Guangxi Zhuang Autonomous Region Center for Disease Prevention and Control, Nanning, Guangxi, 530021, China,Correspondence:
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan, 650500, China,Correspondence:
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