Evaluation of the Double Agar Gel Immunodiffusion Test and of the Enzyme-Linked Immunosorbent Assay in the Diagnosis and Follow-Up of Patients with Chronic Pulmonary Aspergillosis.
The diagnosis of chronic pulmonary aspergillosis (CPA) depends on the radiologic image and the identification of specific antibodies. The present study aimed to evaluate accuracy parameters of enzyme-linked immunosorbent assay (ELISA) and of the determination of serum galactomannan level in the diagnosis of patients with CPA, comparing these results with the double agar gel immunodiffusion (DID) test. In addition, the prevalence of cross-reactivity and the serological progression after treatment were evaluated by comparing DID and ELISA. Six study groups were formed: G1: 22 patients with CPA, 17 of whom had Aspergillus fungus ball, one chronic cavitary pulmonary aspergillosis (CCPA) and four chronic fibrosing pulmonary aspergillosis (CFPA); G2: 28 patients with pulmonary tuberculosis (TB); G3: 23 patients with histoplasmosis (HST); G4: 50 patients with paracoccidioidomycosis (PCM); G5: 20 patients with cryptococcosis (CRC); and G6: 200 healthy controls. Serum antibodies were measured by DID and ELISA, with two antigen preparations--Aspergillus fumigatus (DID1, ELISA1) and a pool of A. fumigatus, A. flavus and A. niger antigens (DID2, ELISA2). The Platélia Aspergillus Enzyme Immunoassay (EIA) kit was used to measure galactomannan. The cut-off points of ELISA were determined for each antigen preparation and for the 95% and 99% confidence intervals. Despite the low sensitivity, DID was the technique of choice due to its specificity, positive and negative predictive values and positive likelihood ratio-especially with the antigen pool and due to the low frequency of cross-reactivity. ELISA1 and a 0.090 cut-off showed high sensitivity, specificity and negative predictive value, but a high frequency of cross-reactivity with CRC. The best degree of agreement was observed between ELISA1 and ELISA2. The detection of serum galactomannan showed high sensitivity, comparable to ELISA2. The immunodiffusion test showed an excellent relationship with the progression after treatment, which made it the reaction of choice for patient follow-up.
Tropical Diseases Department, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo State, Brazil.
Priscila Zacarias
PZ
de Azevedo
Tropical Diseases Department, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo State, Brazil.
Tatiane Fernanda
TF
Sylvestre
Tropical Diseases Department, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo State, Brazil.
Ricardo de Souza
Rde S
Cavalcante
Instituto de Biociências de Botucatu, UNESP, Botucatu, São Paulo State, Brazil.
Lídia Raquel
LR
de Carvalho
Universidade do Oeste Paulista, UNOESTE, Presidente Prudente, São Paulo State, Brazil.
Daniela Vanessa
DV
Moris
Department of Pathology, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo State, Brazil.
Maria Luiza Cotrim Sartor
ML
de Oliveira
Tropical Diseases Department, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo State, Brazil.
Rinaldo Poncio
RP
Mendes
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000946:Antigens, Fungal / Q000097:blood*; D001230:Aspergillus; D002908:Chronic Disease; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D005779:Immunodiffusion / Q000379:methods; D008297:Male; D008875:Middle Aged; D055732:Pulmonary Aspergillosis / Q000097:blood* / Q000175:diagnosis*
D000946:Antigens, Fungal