title: Improved detection of circulating Aspergillus antigen by use of a modified pretreatment procedure.
abstract: Detection of circulating galactofuranose (galf) antigens, including galactomannan (GM), by the Platelia Aspergillus (PA) enzyme-linked immunosorbent assay (ELISA) is an important tool in the early diagnosis of invasive aspergillosis (IA). We used a modified pretreatment technique (MT) on consecutive negative PA ELISA plasma samples from IA patients in order to improve the detection of the fungal components present. Plasma samples (52) were collected from healthy donors, and 174 plasma samples with a galactomannan index (GMI) below 0.5 were collected from 25 unclassifiable and 23 IA patients. The PA ELISA reactivity of pretreated samples was determined before (conventional technique [CT]) and after (MT) filtration using a Microcon filter with a 50-kDa cutoff (Millipore). For the MT, the sensitivity of the PA ELISA increased from 42.9% (CT) to 78.6% (MT) using a cutoff for the GMI of 1.5 in the probable and proven group, whereas specificity slightly decreased from 98.7% to 96.1% in the control group. The 10-fold concentration step increased the GMI as high as 121-fold. The MT resulted not only in positive reactivity in samples that tested negative with the CT but also in the earlier detection of antigen by 2 to 17 days.
authors.affiliation: Department of Medical Microbiology, Radboud University Nijmegen Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands. monique.mennink@gmail.com
authors.forename: Monique A S H
authors.initials: MA
authors.lastname: Mennink-Kersten
authors.forename: Dorien
authors.initials: D
authors.lastname: Ruegebrink
authors.forename: Rocus R
authors.initials: RR
authors.lastname: Klont
authors.forename: Adilia
authors.initials: A
authors.lastname: Warris
authors.forename: Nicole M A
authors.initials: NM
authors.lastname: Blijlevens
authors.forename: J Peter
authors.initials: JP
authors.lastname: Donnelly
authors.forename: Paul E
authors.initials: PE
authors.lastname: Verweij
mesh_terms: D000293:Adolescent; D000328:Adult; D000946:Antigens, Fungal / Q000097:blood*; D001228:Aspergillosis / Q000175:diagnosis* / Q000382:microbiology; D001230:Aspergillus / Q000276:immunology / Q000302:isolation & purification; D002648:Child; D002675:Child, Preschool; D004492:Edetic Acid / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D005690:Galactose / Q000031:analogs & derivatives; D006801:Humans; D008297:Male; D008351:Mannans / Q000097:blood; D008875:Middle Aged; D012680:Sensitivity and Specificity
chemical_list: D000946:Antigens, Fungal; D008351:Mannans; C012990:galactomannan; D004492:Edetic Acid; D005690:Galactose