Visceral Leishmaniasis IgG1 Rapid Monitoring of Cure vs. Relapse, and Potential for Diagnosis of Post Kala-Azar Dermal Leishmaniasis.

Abstract

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.

• Authors: 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 Boelaert, Sayda El-Safi, Shyam Sundar, Michael A Miles
• Journal: Frontiers in cellular and infection microbiology (Front Cell Infect Microbiol) Vol. 8 Pg. 427 ( 2018) ISSN: 2235-2988 [Electronic] Switzerland
• PMID: 30619774 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antigens, Protozoan
• Immunoglobulin G
• Reagent Kits, Diagnostic

Topics

• Antigens, Protozoan (immunology)
• Diagnostic Tests, Routine
• Enzyme-Linked Immunosorbent Assay
• Humans
• Immunoglobulin G (blood)
• Immunologic Tests
• India
• Leishmania donovani (immunology, pathogenicity)
• Leishmaniasis, Cutaneous (diagnosis, immunology)
• Leishmaniasis, Visceral (diagnosis, immunology, therapy)
• Reagent Kits, Diagnostic
• Recurrence
• Sudan