Objectives. Allergic bronchopulmonary aspergillosis (ABPA) is a bronchial-related hypersensitivity reaction involving predominantly Aspergillus fumigatus. It occurs frequently in patients with cystic fibrosis (CF). The diagnosis of ABPA in CF patients remains difficult because clinical signs are common to both diseases (CF and ABPA). ABPA diagnosis is based on clinical, radiological, and biological arguments, including serum anti-Aspergillus antibody detection. The objectives of the present study were: i) to evaluate the two techniques Platelia ™ Aspergillus IgG Biorad® ELISA and Aspergillus LDBIO Diagnostics® Western Blot (WB) for ABPA diagnosis, ii) to choose between two approaches, one that consisted in combining systematically ELISA and WB techniques [ELISA + WB], another one that consisted in performing WB only if ELISA was positive [ELISA +/- WB].

Methods. We retrospectively enrolled 66 CF patients monitored at the CRCM of Roscoff - Perharidy (ILDYS foundation) who had undergone serum anti-Aspergillus antibody detection using ELISA and WB assays from November 2014 to May 2015. These patients were sorted in two groups according to ABPA criteria defined by the ISHAM. The performance of the two assays and the two above approaches were evaluated through sensitivity, specificity, predictive value (PPV, NPV), and likelihood ratio (LR+, LR-) assessment.

Results. The sensitivity, specificity, PPV, NPV, LR+, LR- were 100%, 58%, 11%, 100%, 2.4, and 0 respectively for the ELISA assay. The sensitivity, specificity, PPV, NPV, LR+, LR- were 100%, 26%, 7%, 100%, 1.4, and 0 respectively for the WB assay. The sensitivity, specificity, LR+, LR- were 100%, 15%, 1.2, and 0 respectively for the [ELISA + WB] approach. The sensitivity, specificity, LR+, LR- were 100%, 63%, 2.7, and 0 respectively for the [ELISA +/- WB] approach.  

Conclusion. The results show a better performance of the [ELISA +/- WB] approach. According to this approach a negative result provides a strong argument to rule out ABPA diagnosis.

Evaluation of the Platelia™ Aspergillus IgG Biorad®ELISA and Aspergillus LDBIO Diagnostics® Western Blot for ABPA diagnosis in cystic fibrosis patients.