title: Immunodiagnosis of paracoccidioidomycosis due to Paracoccidioides brasiliensis using a latex test: detection of specific antibody anti-gp43 and specific antigen gp43.
abstract: BACKGROUND
  Paracoccidioidomycosis (PCM) is a life-threatening systemic disease and is a neglected public health problem in many endemic regions of Latin America. Though several diagnostic methods are available, almost all of them present with some limitations.
  A latex immunoassay using sensitized latex particles (SLPs) with gp43 antigen, the immunodominant antigen of Paracoccidioides brasiliensis, or the monoclonal antibody mAb17c (anti-gp43) was evaluated for antibody or antigen detection in sera, cerebrospinal fluid (CSF), and bronchoalveolar lavage (BAL) from patients with PCM due to P. brasiliensis. The gp43-SLPs performed optimally to detect specific antibodies with high levels of sensitivity (98.46%, 95% CI 91.7-100.0), specificity (93.94%, 95% CI 87.3-97.7), and positive (91.4%) and negative (98.9%) predictive values. In addition, we propose the use of mAb17c-SLPs to detect circulating gp43, which would be particularly important in patients with immune deficiencies who fail to produce normal levels of immunoglobulins, achieving good levels of sensitivity (96.92%, 95% CI 89.3-99.6), specificity (88.89%, 95% CI 81.0-94.3), and positive (85.1%) and negative (97.8%) predictive values. Very good agreement between latex tests and double immune diffusion was observed for gp43-SLPs (k = 0.924) and mAb17c-SLPs (k = 0.850), which reinforces the usefulness of our tests for the rapid diagnosis of PCM in less than 10 minutes. Minor cross-reactivity occurred with sera from patients with other fungal infections. We successfully detected antigens and antibodies from CSF and BAL samples. In addition, the latex test was useful for monitoring PCM patients receiving therapy.
  
  
  CONCLUSIONS
  The high diagnostic accuracy, low cost, reduced assay time, and simplicity of this new latex test offer the potential to be commercialized and makes it an attractive diagnostic assay for use not only in clinics and medical mycology laboratories, but mainly in remote locations with limited laboratory infrastructure and/or minimally trained community health workers.
authors: Federal University of São Paulo, Department of Microbiology, Immunology and Parasitology, Cell Biology Division, São Paulo, Brazil.
authors: Priscila Oliveira
authors: PO
authors: Dos Santos
authors: Federal University of São Paulo, Department of Microbiology, Immunology and Parasitology, Cell Biology Division, São Paulo, Brazil.
authors: Anderson Messias
authors: AM
authors: Rodrigues
authors: Federal University of São Paulo, Department of Microbiology, Immunology and Parasitology, Cell Biology Division, São Paulo, Brazil.
authors: Geisa Ferreira
authors: GF
authors: Fernandes
authors: Evandro Chagas Institute, Bacteriology and Mycology Division, Ananindeua, Pará, Brazil.
authors: Silvia Helena Marques
authors: SH
authors: da Silva
authors: Federal University of Alfenas, Institute of Biomedical Sciences, Alfenas, Minas Gerais, Brazil.
authors: Eva
authors: E
authors: Burger
authors: Federal University of São Paulo, Department of Microbiology, Immunology and Parasitology, Cell Biology Division, São Paulo, Brazil.
authors: Zoilo Pires
authors: ZP
authors: de Camargo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology; D000913:Antibodies, Protozoan / Q000032:analysis / Q000097:blood / Q000276:immunology; D000946:Antigens, Fungal / Q000032:analysis* / Q000097:blood / Q000134:cerebrospinal fluid; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005656:Fungal Proteins / Q000032:analysis* / Q000097:blood / Q000134:cerebrospinal fluid; D006023:Glycoproteins / Q000032:analysis* / Q000097:blood / Q000134:cerebrospinal fluid; D006801:Humans; D007841:Latex Fixation Tests; D007843:Latin America; D008297:Male; D008875:Middle Aged; D010228:Paracoccidioides / Q000276:immunology*; D010229:Paracoccidioidomycosis / Q000175:diagnosis* / Q000276:immunology; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: C103180:43 kDa protein, Paracoccidioides; D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000946:Antigens, Fungal; D005656:Fungal Proteins; D006023:Glycoproteins