In situ indirect fluorescent antibody: a new specific test to detect ongoing chagasic infections.
In situ immunofluorescence assay (ISIFA) was developed for the selection for treatment of chronically infected chagasic patients and their follow-up. Trypomastigotes flash fixed in situ on microscopic slides with 0.025% glutaraldehyde were used as antigen. ISIFA results were compared with complement-mediated lysis (CoML), membrane immunofluorescence (MbIFA), immunofluorescence assay (IFA) with epimastigotes, and xenodiagnosis (XENO). ISIFA was able to distinguish nontreated chagasic patients (geometric mean titer [GMT] = 180) and treatment failures (GMT = 160) from those considered successfully treated (GMT = 25). ISIFA revealed a high sensitivity and titers of 80 or higher detected 98.6% of patients with active infections, even in those with negative XENO, CoML, or MbIFA. Specificity evaluated in 63 sera from other infections, including leishmaniasis and autoimmune diseases, was 98%. IFA used in routine diagnostic procedures exhibited similar results in all groups, irrespective of therapy.
Levy
A M
AM
Instituto Dante Pazzanese de Cardiologia, São Paulo University, Brasil.
Boainain
E
E
Kloetzel
J K
JK
D000328:Adult; D000913:Antibodies, Protozoan; D015415:Biomarkers; D014355:Chagas Disease / Q000175:diagnosis* / Q000276:immunology; D002648:Child; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005976:Glutaral; D006801:Humans; D008297:Male; D008875:Middle Aged; D015800:Protozoan Proteins / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000913:Antibodies, Protozoan; D015415:Biomarkers; D015800:Protozoan Proteins; D005976:Glutaral