Leprosy Mailing List – February 26, 2013
Ref.: (LML) New Diagnostic Test
From: Dr. Malcolm S Duthie, Seattle, USA
Dear Dr. Schreuder,
I'd greatly appreciate it if you could post the following message to the Leprosy Mailing List.
We've received many similar questions regarding the rapid diagnostic test for leprosy, developed by IDRI in conjunction with OrangeLife, that is now registered through the regulatory body (ANVISA) in Brazil. This news was disseminated in a press release at the end of January, then picked up and publicized last week by the New York Times and slate.com (and subsequently many other news outlets).
We've generated a panel of questions and answers in response to the most often asked questions and this is included below. For further information regarding the procurement of tests, OrangeLife can be contacted directly through their website. Feedback and expression of interest/ intent is appreciated and will be instructive in determining the size of production runs they will need to make.
I've also provided a list of the publications pertinent to the antigens incorporated in the tests and the various indications (diagnosis, prognosis, measuring treatment) that we have examined in lab-based assays. These assays were fore-runners to the development of the rapid diagnostic test.
Best wishes, Malcolm
Dr. Malcolm S Duthie
Senior Scientist
Infectious Disease Research Institute
Suite 400, 1124 Columbia St
Seattle, WA 98104
Tel – (206) 330 2517
Fax – (206) 381 3678
- How exactly does the detection of the infection work?
In our leprosy rapid diagnostic test (RDT), we detect and measure antibodies that are produced by infected individuals and found within their blood/ serum. These antibodies react with a combination of M. leprae proteins and glycolipid. These reactions lead to a the appearance of a colored band in a window (the test configuration is analogous to a pregnancy kit) when sample from a leprosy patient is added. The result can be read by eye, or read and accurately measured with enhanced sensitivity and in a standardized fashion by OrangeLife's SmartReader.
- Do you know how sensitive and specific the test is?
The rapid diagnostic test is registered with label claim of 95% sensitivity for MB leprosy, with 100% specificity against the validation serum panel used. We have ongoing evaluations that are not only expanding our own data but assessing test robustness etc.. As with any test, a broader picture of its performance and capabilities will emerge only as it is disseminated and becomes more widely used in field settings.
- Is it available for diagnosis in countries other than Brazil available?
While the test is registered in Brazil, actual use of the test results a 'primary' diagnostic criterion will be dependent on the regulations within any particular country. Further details regarding procurement of tests can be obtained from OrangeLife (http://www.orangelife.com.br/ ).
- What is the scientific background that supports the test?
A combination of LID-1 and NDO is incorporated in RDT. IDRI has several scientific publications (see below) relating to lab-based research conducted over the last few years with regard to the LID-1 antigen and there is a long history of publications regarding NDO (a synthetic mimetic of phenolic glycolipid-I).
1. Qiong-Hua P, Zhong-Yi Z, Jun Y, Yan W, Lian-Chao Y, Huan-Ying L, Reed SG, Duthie MS. 2013. Early Revelation of Leprosy in China by Sequential Antibody Analyses with LID-1 and PGL-I. Journal of Tropical Medicine 2013: 352689
2. Duthie MS, Goto W, Ireton GC, Reece ST, Cardoso LP, Martelli CM, Stefani MM, Nakatani M, de Jesus RC, Netto EM, Balagon MV, Tan E, Gelber RH, Maeda Y, Makino M, Hoft D, Reed SG. 2007. Use of protein antigens for early serological diagnosis of leprosy. Clin Vaccine Immunol 14: 1400-8
3. Duthie MS, Hay MN, Rada EM, Convit J, Ito L, Oyafuso LK, Manini MI, Goulart IM, Lobato J, Goulart LR, Carter D, Reed SG. 2011. Specific IgG antibody responses may be used to monitor leprosy treatment efficacy and as recurrence prognostic markers. European Journal of Clinical Microbiology & Infectious Diseases 30: 1257-65
4. Duthie MS, Truman RW, Goto W, O'Donnell J, Hay MN, Spencer JS, Carter D, Reed SG. 2011. Insight toward early diagnosis of leprosy through analysis of the developing antibody responses of Mycobacterium leprae-infected armadillos. Clinical and vaccine immunology : CVI 18: 254-9
5. Hungria E, Oliveira R, Sousa AL, Costa MB, Brito de Souza V, Moreno F, Nogueira M, Costa M, Silva S, Buhrer-Sekula S, Reed SG, Duthie MS, Silva E, Stefani MM. 2012. Seroreactivity to new Mycobacterium leprae protein antigens in different leprosy endemic regions in Brazil. Mem Inst Oswaldo Cruz 107, suppl.1: 104-11
6. Rada E, Duthie MS, Reed SG, Aranzazu N, Convit J. 2012. Serologic Follow-up of IgG Responses Against Recombinant Mycobacterial Proteins ML0405, ML2331 and LID-1 in a Leprosy Hyperendemic Area of Venezuela. Mem Inst Oswaldo Cruz 107, suppl.1: 90-4
7. Spencer J, Duthie MS, Geluk A, Balagon M, Kim H, Wheat WH, Chatterjee D, Jackson M, Li W, Kurihara J, Maghanoy A, Mallari I, Saunderson P, Brennan P, Dockrell DH. 2012. Identification of Serological Biomarkers of Infection, Disease Progression and Treatment Efficacy for Leprosy. Mem Inst Oswaldo Cruz 107, suppl.1: 79-89
LML - S Deepak, B Naafs, S Noto and P Schreuder
LML Archives: http://www.aifo.it/english/resources/online/lml-archives/index.htm
Contact: Dr Pieter Schreuder << editorlml@gmail.com >>.
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