Application of an improved method for the recombinant K39 enzyme-linked immunosorbent assay to detect visceral leishmaniasis disease and infection in Bangladesh

K. M. Kurkjian, L. E. Vaz, R. Haque, C. Cetre-Sossah, S. Akhter, S. Roy, F. Steurer, J. Amann, M. Ali, R. Chowdhury, Y. Wagatsuma, J. Williamson, S. Crawford, R. F. Breiman, J. H. Maguire, C. Bern, W. E. Secor

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Several serology-based immunoassays are used to diagnose visceral leishmaniasis (VL), a chronic protozoan parasitic disease caused by the Leishmania donovani complex. These tests are primarily designed to diagnose the most severe clinical form of VL, known as kala-azar. However, leishmanial infection is frequently asymptomatic and may manifest only as a positive serologic response or positive leishmanin skin test. We modified a previously described enzyme-linked immunosorbent assay (ELISA) that detects patient antibodies reactive with the recombinant Leishmania protein K39 (rK39) to confirm suspected kala-azar and to detect asymptomatic infection in a community study in Bangladesh. With the inclusion of a standard curve on each ELISA plate, the rK39 ELISA was more repeatable (kappa coefficient of agreement = 0.970) and more reliable compared to the original method (kappa = 0.587, P < 0.001). The cutoff point for a positive antibody response was chosen based on the 99th percentile of the ELISA distribution for the negative-control sera. However, we found that sera from all patients with active kala-azar yielded values more than twice the magnitude of this cutoff. Using receiver-operator characteristic curves, we determined a second cutoff value predictive of kala-azar. Using these criteria, the sensitivity and specificity of the modified ELISA for kala-azar were 97.0% and 98.9%, respectively, for sera from our study population. We hypothesize that individuals with antibody levels greater than the 99th percentile of the negative controls but less than the cutoff point for kala-azar have asymptomatic leishmanial infections.

Original languageEnglish (US)
Pages (from-to)1410-1415
Number of pages6
JournalClinical and Diagnostic Laboratory Immunology
Volume12
Issue number12
DOIs
StatePublished - Dec 2005

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Clinical Biochemistry
  • Microbiology (medical)

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    Kurkjian, K. M., Vaz, L. E., Haque, R., Cetre-Sossah, C., Akhter, S., Roy, S., Steurer, F., Amann, J., Ali, M., Chowdhury, R., Wagatsuma, Y., Williamson, J., Crawford, S., Breiman, R. F., Maguire, J. H., Bern, C., & Secor, W. E. (2005). Application of an improved method for the recombinant K39 enzyme-linked immunosorbent assay to detect visceral leishmaniasis disease and infection in Bangladesh. Clinical and Diagnostic Laboratory Immunology, 12(12), 1410-1415. https://doi.org/10.1128/CDLI.12.12.1410-1415.2005