Visceral leishmaniasis IgG1 rapid monitoring of cure vs. relapse, and potential for diagnosis of post kala-azar dermal leishmaniasis

Tegwen Marlais, Tapan Bhattacharyya, Om Prakash Singh, Pascal Mertens, Quentin Gilleman, Caroline Thunissen, Bruno C. Bremer Hinckel, Callum Pearson, Bathsheba L. Gardner, Stephanie Airs, Marianne de la Roche, Kiera Hayes, Hannah Hafezi, Andrew K. Falconar, Osama Eisa, Alfarazdeg Saad, Basudha Khanal, Narayan Raj Bhattarai, Suman Rijal, Marleen BoelaertSayda El-Safi, Shyam Sundar, Michael A. Miles

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    Background: There is a recognized need for an improved diagnostic test to assess post-chemotherapeutic treatment outcome in visceral leishmaniasis (VL) and to diagnose post kala-azar dermal leishmaniasis (PKDL). We previously demonstrated by ELISA and a prototype novel rapid diagnostic test (RDT), that high anti-Leishmania IgG1 is associated with post-treatment relapse versus cure in VL.

    Methodology: Here, we further evaluate this novel, low-cost RDT, named VL Sero K-SeT, and ELISA for monitoring IgG1 levels in VL patients after treatment. IgG1 levels against L. donovani lysate were determined. We applied these assays to Indian sera from cured VL at 6 months post treatment as well as to relapse and PKDL patients. Sudanese sera from pre- and post-treatment and relapse were also tested.

    Results: Of 104 paired Indian sera taken before and after treatment for VL, when deemed clinically cured, 81 (77.9%) were positive by VL Sero K-SeT before treatment; by 6 months, 68 of these 81 (84.0%) had a negative or reduced RDT test line intensity. ELISAs differed in positivity rate between pre- and post-treatment (p = 0.0162). Twenty eight of 33 (84.8%) Indian samples taken at diagnosis of relapse were RDT positive. A comparison of Indian VL Sero K-SeT data from patients deemed cured and relapsed confirmed that there was a significant difference (p <0.0001) in positivity rate for the two groups using this RDT. Ten of 17 (58.8%) Sudanese sera went from positive to negative or decreased VL Sero K-SeT at the end of 11-30 days of treatment. Forty nine of 63 (77.8%) PKDL samples from India were positive by VL Sero K-SeT.

    Conclusion: We have further shown the relevance of IgG1 in determining clinical status in VL patients. A positive VL Sero K-SeT may also be helpful in supporting diagnosis of PKDL. With further refinement, such as the use of specific antigens, the VL Sero K-SeT and/or IgG1 ELISA may be adjuncts to current VL control programmes.

    Original languageEnglish
    Article number427
    JournalFrontiers in Cellular and Infection Microbiology
    Number of pages10
    Publication statusPublished - 2018


    • visceral leishmaniasis
    • serology
    • treatment
    • relapse
    • cure
    • IgG1
    • RDT
    • PKDL
    • BIHAR
    • AREAS
    • TESTS

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