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Inaccuracy of enzyme-linked immunosorbent assay using soluble and recombinant antigens to detect asymptomatic infection by Leishmania infantum.
PLoS Negl Trop Dis. 2009 Oct 20; 3(10):e536.PN

Abstract

BACKGROUND

One of the most important drawbacks in visceral leishmaniasis (VL) population studies is the difficulty of diagnosing asymptomatic carriers. The aim of this study, conducted in an urban area in the Southeast of Brazil, was to evaluate the performance of serology to identify asymptomatic VL infection in participants selected from a cohort with a two-year follow-up period.

METHODOLOGY

Blood samples were collected in 2001 from 136 cohort participants (97 positive and 39 negatives, PCR/hybridization carried out in 1999). They were clinically evaluated and none had progressed to disease from their asymptomatic state. As controls, blood samples from 22 control individuals and 8 patients with kala-azar were collected. Two molecular biology techniques (reference tests) were performed: PCR with Leishmania-generic primer followed by hybridization using L. infantum probe, and PCR with specific primer to L. donovani complex. Plasma samples were tested by ELISA using three different antigens: L. infantum and L. amazonensis crude antigens, and rK39 recombinant protein. Accuracy of the serological tests was evaluated using sensitivity, specificity, likelihood ratio and ROC curve.

FINDINGS

The presence of Leishmania was confirmed, by molecular techniques, in all kala-azar patients and in 117 (86%) of the 136 cohort participants. Kala-azar patients showed high reactivity in ELISAs, whereas asymptomatic individuals presented low reactivity against the antigens tested. When compared to molecular techniques, the L. amazonensis and L. infantum antigens showed higher sensitivity (49.6% and 41.0%, respectively) than rK39 (26.5%); however, the specificity of rK39 was higher (73.7%) than L. amazonensis (52.6%) and L. infantum antigens (36.8%). Moreover, there was low agreement among the different antigens used (kappa<0.10).

CONCLUSIONS

Serological tests were inaccurate for diagnosing asymptomatic infections compared to molecular methods; this could lead to misclassification bias in population studies. Therefore, studies which have used serological assays to estimate prevalence, to evaluate intervention programs or to identify risk factors for Leishmania infection, may have had their results compromised.

Authors+Show Affiliations

Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Programa de Pós-Graduação em Parasitologia, Minas Gerais, Brasil.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Evaluation Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19841736

Citation

Moreno, Elizabeth Castro, et al. "Inaccuracy of Enzyme-linked Immunosorbent Assay Using Soluble and Recombinant Antigens to Detect Asymptomatic Infection By Leishmania Infantum." PLoS Neglected Tropical Diseases, vol. 3, no. 10, 2009, pp. e536.
Moreno EC, Gonçalves AV, Chaves AV, et al. Inaccuracy of enzyme-linked immunosorbent assay using soluble and recombinant antigens to detect asymptomatic infection by Leishmania infantum. PLoS Negl Trop Dis. 2009;3(10):e536.
Moreno, E. C., Gonçalves, A. V., Chaves, A. V., Melo, M. N., Lambertucci, J. R., Andrade, A. S., Negrão-Corrêa, D., de Figueiredo Antunes, C. M., & Carneiro, M. (2009). Inaccuracy of enzyme-linked immunosorbent assay using soluble and recombinant antigens to detect asymptomatic infection by Leishmania infantum. PLoS Neglected Tropical Diseases, 3(10), e536. https://doi.org/10.1371/journal.pntd.0000536
Moreno EC, et al. Inaccuracy of Enzyme-linked Immunosorbent Assay Using Soluble and Recombinant Antigens to Detect Asymptomatic Infection By Leishmania Infantum. PLoS Negl Trop Dis. 2009 Oct 20;3(10):e536. PubMed PMID: 19841736.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Inaccuracy of enzyme-linked immunosorbent assay using soluble and recombinant antigens to detect asymptomatic infection by Leishmania infantum. AU - Moreno,Elizabeth Castro, AU - Gonçalves,Andréa Vieira, AU - Chaves,Anderson Vieira, AU - Melo,Maria Norma, AU - Lambertucci,José Roberto, AU - Andrade,Antero Silva Ribeiro, AU - Negrão-Corrêa,Deborah, AU - de Figueiredo Antunes,Carlos Mauricio, AU - Carneiro,Mariângela, Y1 - 2009/10/20/ PY - 2008/12/22/received PY - 2009/09/24/accepted PY - 2009/10/21/entrez PY - 2009/10/21/pubmed PY - 2009/12/22/medline SP - e536 EP - e536 JF - PLoS neglected tropical diseases JO - PLoS Negl Trop Dis VL - 3 IS - 10 N2 - BACKGROUND: One of the most important drawbacks in visceral leishmaniasis (VL) population studies is the difficulty of diagnosing asymptomatic carriers. The aim of this study, conducted in an urban area in the Southeast of Brazil, was to evaluate the performance of serology to identify asymptomatic VL infection in participants selected from a cohort with a two-year follow-up period. METHODOLOGY: Blood samples were collected in 2001 from 136 cohort participants (97 positive and 39 negatives, PCR/hybridization carried out in 1999). They were clinically evaluated and none had progressed to disease from their asymptomatic state. As controls, blood samples from 22 control individuals and 8 patients with kala-azar were collected. Two molecular biology techniques (reference tests) were performed: PCR with Leishmania-generic primer followed by hybridization using L. infantum probe, and PCR with specific primer to L. donovani complex. Plasma samples were tested by ELISA using three different antigens: L. infantum and L. amazonensis crude antigens, and rK39 recombinant protein. Accuracy of the serological tests was evaluated using sensitivity, specificity, likelihood ratio and ROC curve. FINDINGS: The presence of Leishmania was confirmed, by molecular techniques, in all kala-azar patients and in 117 (86%) of the 136 cohort participants. Kala-azar patients showed high reactivity in ELISAs, whereas asymptomatic individuals presented low reactivity against the antigens tested. When compared to molecular techniques, the L. amazonensis and L. infantum antigens showed higher sensitivity (49.6% and 41.0%, respectively) than rK39 (26.5%); however, the specificity of rK39 was higher (73.7%) than L. amazonensis (52.6%) and L. infantum antigens (36.8%). Moreover, there was low agreement among the different antigens used (kappa<0.10). CONCLUSIONS: Serological tests were inaccurate for diagnosing asymptomatic infections compared to molecular methods; this could lead to misclassification bias in population studies. Therefore, studies which have used serological assays to estimate prevalence, to evaluate intervention programs or to identify risk factors for Leishmania infection, may have had their results compromised. SN - 1935-2735 UR - https://www.unboundmedicine.com/medline/citation/19841736/Inaccuracy_of_enzyme_linked_immunosorbent_assay_using_soluble_and_recombinant_antigens_to_detect_asymptomatic_infection_by_Leishmania_infantum_ L2 - https://dx.plos.org/10.1371/journal.pntd.0000536 DB - PRIME DP - Unbound Medicine ER -