American tegumentary leishmaniasis diagnosis using L. (V.) braziliensis fixed promastigotes: a comparative performance of serological tests and spontaneous cure identification

Abstract

BackgroundThe present study aimed to demonstrate the applicability of a flow cytometry-based serology approach to identify spontaneous cure by the detection of immunoglobulin G, and also, the diagnosis and cure criterion by the IgG1 isotype in American Tegumentary Leishmaniasis – ATL caused by L. (V.) braziliensis. Also, a comparison between flow cytometry with the serological conventional technique was performed.MethodsForty five individuals were included in study. They were assessed in two moments: First, 8 subjects spontaneously cured of ATL, 8 healthy individuals and 15 patients who had a positive diagnosis for ATL were selected before treatment to identify spontaneous cure by immunoglobulin G detection. Secondly, 14 patients who were positive for ATL were selected and had their blood collected before and 1, 2 and 5 years after treatment, respectively, for the diagnostic tests (ELISA and flow cytometry) and cure criterion evaluation using the IgG1 isotype.ResultsThe analysis of the mean percentage of positive fluorescent parasites (PPFP) along with the titration curves of IgG anti-fixed promastigotes of L.(V.)braziliensis, confirmed the applicability of this method for monitoring spontaneous cure in ATL with outstanding co-positivity (100%) and co-negativity (100%) performance indexes. Regarding the results of the comparison between flow cytometry and ELISA it was seen that there was a better accuracy of the first one in relation to the other. When IgG1 applicability was evaluated, it was observed that before treatment, 36.8% of the patients were negative; in patients 1 year post-treatment, 82.3%; 2 years post-treatment, 27.2% and in patients 5 years post-treatment, 87.5%. The overall analysis of the results suggests that flow cytometry can be applied to ATL detection, and that the use of IgG1 isotype has possibilities to contribute as a more specific diagnostic method.ConclusionsTherefore, this area has great perspectives use for the diagnosis and cure criterion, and also it can be scaled up with the possibility to characterize the different clinical stages of the disease. Together, these findings demonstrate the applicability of a flow cytometry-based serology approach and opens up new avenues of research with this technique, such as the understanding the humoral response in ATL patients.

Clinical and parasitological features of Leishmania infection among gold miners in the Oiapoque basin, an international Brazil-French Guiana border

“…The frequency of positive anti- Leishmania antibodies was high (in eight of nine patients), especially for IgG1, a Th1-induced IgG subclass. This finding is in accordance with others that showed IgG1 is a promising serologic biomarker for ATL diagnosis [ 26 , 36 ]. On the other hand, the IGRA-Leish results showed that almost half (5 out 9) of the patients had a low capacity to produce IFN-gamma by specific peripheral blood cells, an important effector cytokine induced by Leishmania antigens.…”

“…Epidemiological surveys to identify people infected with Leishmania are commonly performed through serological tests of low sensitivity, especially for recent infections or for individuals with more than two years of successful cure after CL treatment [ 26 , 36 ]. Surveys based on the detection of the cellular immune response have also been reported [ 37 ], but due to the discontinuation of the MST antigens, this is no longer an available alternative [ 34 ].…”

Sensitive and specific serodiagnosis of tegumentary leishmaniasis using a new chimeric protein based on specific B-cell epitopes of Leishmania antigenic proteins

“…However, in the TL, the anti-parasite antibody production is usually lower against Leishmania antigens, mainly in CL cases, and diagnostic tests are not effective to detect the disease [34].…”

A Flow Cytometry-Based Serological Assay to Detect Visceral Leishmaniasis in HIV-Infected Patients

“…This technique has several advantages for immunoassays, such as high throughput capacity, possibility of analyte quantification, reduced sample volume, high reproducibility and sensitivity (14,15). More importantly, it allows the development of multiplex studies using recombinant antigens, and it can be used as a monitoring tool for cured patients, allowing a more sensitive detection of anti-Leishmania antibodies (16)(17)(18). Therefore, the aim of this study was to evaluate the performance and to verify the possible application of an alternative diagnostic method using flow cytometry to detect anti-L. infantum antibodies in HIVinfected patients.…”