title: Use of a Chagas Urine Nanoparticle Test (Chunap) to Correlate with Parasitemia Levels in T. cruzi/HIV Co-infected Patients.
abstract: BACKGROUND
  Early diagnosis of reactivated Chagas disease in HIV patients could be lifesaving. In Latin America, the diagnosis is made by microscopical detection of the T. cruzi parasite in the blood; a diagnostic test that lacks sensitivity. This study evaluates if levels of T. cruzi antigens in urine, determined by Chunap (Chagas urine nanoparticle test), are correlated with parasitemia levels in T. cruzi/HIV co-infected patients.
  
  
  RESULTS
  T. cruzi antigens in urine of HIV patients (N = 55: 31 T. cruzi infected and 24 T. cruzi serology negative) were concentrated using hydrogel particles and quantified by Western Blot and a calibration curve. Reactivation of Chagas disease was defined by the observation of parasites in blood by microscopy. Parasitemia levels in patients with serology positive for Chagas disease were classified as follows: High parasitemia or reactivation of Chagas disease (detectable parasitemia by microscopy), moderate parasitemia (undetectable by microscopy but detectable by qPCR), and negative parasitemia (undetectable by microscopy and qPCR). The percentage of positive results detected by Chunap was: 100% (7/7) in cases of reactivation, 91.7% (11/12) in cases of moderate parasitemia, and 41.7% (5/12) in cases of negative parasitemia. Chunap specificity was found to be 91.7%. Linear regression analysis demonstrated a direct relationship between parasitemia levels and urine T. cruzi antigen concentrations (p<0.001). A cut-off of > 105 pg was chosen to determine patients with reactivation of Chagas disease (7/7). Antigenuria levels were 36.08 times (95% CI: 7.28 to 64.88) higher in patients with CD4+ lymphocyte counts below 200/mL (p = 0.016). No significant differences were found in HIV loads and CD8+ lymphocyte counts.
  
  
  CONCLUSIONS
  Chunap shows potential for early detection of Chagas reactivation. With appropriate adaptation, this diagnostic test can be used to monitor Chagas disease status in T. cruzi/HIV co-infected patients.
authors.affiliation: Laboratorio de Investigación en Enfermedades Infecciosas, Universidad Peruana Cayetano Heredia, Lima, Peru.|Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, Virginia, United States of America.
authors.forename: Yagahira E
authors.initials: YE
authors.lastname: Castro-Sesquen
authors.affiliation: Department of International Health, Bloomberg School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Gilman
authors.affiliation: Colectivo de Estudios Aplicados, Desarrollo Social, Salud y Medio Ambiente, Cochabamba, Bolivia.
authors.forename: Carolina
authors.initials: C
authors.lastname: Mejia
authors.affiliation: Department of Internal Medicine and Pediatrics, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Clark
authors.affiliation: Division of Cardiovascular Medicine, University of California Davis, Davis, California, United States of America.
authors.forename: Jeong
authors.initials: J
authors.lastname: Choi
authors.affiliation: Tulane University Medical Center, New Orleans, Louisiana, United States of America.
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Reimer-McAtee
authors.affiliation: Servicio de Infectología, Hospital Clínico Viedma, Cochabamba, Bolivia.
authors.forename: Rosario
authors.initials: R
authors.lastname: Castro
authors.affiliation: Laboratorio de Investigación en Enfermedades Infecciosas, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Edward
authors.initials: E
authors.lastname: Valencia-Ayala
authors.affiliation: Hospital San Juan De Dios, Santa Cruz de la Sierra, Bolivia.
authors.forename: Jorge
authors.initials: J
authors.lastname: Flores
authors.affiliation: School of Medicine, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America.
authors.forename: Natalie
authors.initials: N
authors.lastname: Bowman
authors.affiliation: Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Castillo-Neyra
authors.affiliation: Facultad de Medicina, Universidad Mayor de San Simón, Cochabamba, Bolivia.
authors.forename: Faustino
authors.initials: F
authors.lastname: Torrico
authors.affiliation: Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, Virginia, United States of America.
authors.forename: Lance
authors.initials: L
authors.lastname: Liotta
authors.affiliation: Global Health Sciences, Department of Epidemiology and Biostatistics, School of Medicine, University of California, San Francisco, San Francisco, California, United States of America.
authors.forename: Caryn
authors.initials: C
authors.lastname: Bern
authors.affiliation: Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, Virginia, United States of America.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Luchini
mesh_terms: D000328:Adult; D000953:Antigens, Protozoan / Q000652:urine*; D018414:CD8-Positive T-Lymphocytes; D016022:Case-Control Studies; D014355:Chagas Disease / Q000150:complications / Q000175:diagnosis* / Q000469:parasitology / Q000652:urine; D060085:Coinfection / Q000175:diagnosis* / Q000276:immunology / Q000469:parasitology / Q000652:urine; D003955:Diagnostic Tests, Routine / Q000295:instrumentation / Q000379:methods*; D042241:Early Diagnosis; D005260:Female; D015658:HIV Infections / Q000150:complications* / Q000652:urine; D006801:Humans; D008297:Male; D008875:Middle Aged; D053758:Nanoparticles / Q000737:chemistry; D018512:Parasitemia / Q000175:diagnosis* / Q000276:immunology / Q000469:parasitology / Q000652:urine; D014349:Trypanosoma cruzi / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D000953:Antigens, Protozoan