Novel non-invasive antigen detection assay for the diagnosis of active visceral leishmaniasis and to monitor the therapy efficacy of this disease

ABSTRACTThe overall goal of this Phase II project is to validate novel leishmanial protein biomarkers for development of a non invasive urine based assay to diagnose active visceral leishmaniasisVLand to monitor the therapeutic efficacy of this serious diseaseVL is endemic incountriesaffectspeople a year and kills more thanof them children under ageVLalso known as kala azaris caused by parasites of the Leishmania donovani complexLdonovani and Larchibaldi in the Old Worldprimarily India and South Eastern Africaand Linfantum in the New WorldSouthern Europe and South AmericaGlobal VL morbidity and mortality in many parts of the world are increasing due to co infection with human immunodeficiency virusAlthough VL is usually fatal if not treated promptlythe effective drugs are toxicexpensive and difficult to administerand untreated people with VL are reservoirs of infection who put others in their communities at riskThe gold standard for diagnosis is observation of the parasitesor detection of parasite DNAin spleenliverlymph node or bone marrow aspiratesserum tests measure antiparasite antibodieswhich cannot distinguish between active VL from either prior exposure to the parasite or subsequent to successful treatment of the diseaseThere is no vaccine for human VLThe WHO has defined that a key requirement for effective control of this serious worldwide disease is a sensitive non invasive test that can rapidly and reliably diagnose active VL and identify people who need immediate treatmentOur former published work and the Phase I component of this Phase II application have established the foundation for the development of a simple non invasive urine test to both diagnose active VL and to monitor the therapy efficacy of this diseaseWe used mass spectroscopy to initially identify three Linfantum and more recently four new Ldonovani proteins excreted in the urine of VL patientsWe characterized these antigensraised polyclonal antibodies against them and developed an antigen detection capture ELISA to diagnose VLA pilot clinical study defined that the three proteins of Linfantum were present in the urineswell characterized New World VL patients and in none of more thancontrol urines samples from healthy subjects as well as from non VL patients like suffering from cutaneous leishmaniasisChagasdiseaseschistosomiasis and tuberculosisWe are currently validating the recently discovered Ldonovani markersFor this Phase II proposal we will use a large panel of urine samples from different areas of the world where VL is endemic to validate all seven discovered Linfantum and Ldonovani biomarkers as reliable tools for the accurate diagnosis of active VL and to monitor the therapy of this diseaseIn addition to a solid preliminary dataa strength of this proposal is our access to a unique resource of urine samples from confirmed VL patients from VL endemic regions around the world Project Narrative Visceral leishmaniasisVLa serious disease caused by the parasites Leishmania donovani Leishmania infantumThe disease affectspeople a year and kills more thanof them children under ageDiagnosis is usually carried out using invasive and inadequate testsliverspleenor bone marrow biopsiesand or by antibody detection tests that cannot distinguish active disease from previously sensitized healthy subjects or from treated and cured patientsThe present project proposes to validate a unique non invasive reliable assay that we have developed for the accurate diagnosis of this diseaseThe assay detects Leishmania proteins that are eliminated in patient s urineSuch test distinguishes active disease from both previously sensitized healthy subjects and from cured patientsIn additionthe assay will be a useful tool to monitor the therapy of VLan unmet and much needed tool because the therapeutic drugs are toxic and because of the alarming increase in parasite resistance to the available drugs