Identification of distinct immunophenotypes in chronic pulmonary aspergillosis using cluster analysis

BackgroundWhether chronic pulmonary aspergillosis (CPA) has different immunophenotypes remains unknown. ObjectiveTo identify different CPA immunophenotypes using cluster analysis. MethodsWe used a subject-centred multivariate clustering approach without prior assumptions to identify CPA phenotypes. We retrospectively included the data of treatment-naive subjects with CPA and excluded subjects with asthma and allergic bronchopulmonary aspergillosis (ABPA). We performed a scalable two-step cluster analysis using the log-likelihood distance measures to identify CPA phenotypes based on the blood immunological profile (total IgE, eosinophil count and Aspergillus-specific IgE and IgG). ResultsWe included 351 CPA subjects and found two clusters. Cluster 2 (n = 118) had significantly higher serum total IgE, peripheral blood eosinophil count, and serum A. fumigatus-specific IgE and IgG than cluster 1 (n = 233). Cluster 2 subjects had a lower FEV1:FVC ratio on spirometry and were more likely to have a fungal ball (88 [74.6%] vs. 145 (62.2%), p = .023) on the CT thorax than cluster 1. After treatment discontinuation, cluster 2 had a longer median (interquartile range) time to relapse than cluster 1 (11.5 [7.3-27.4] vs. 4 [1.1-8.9] months, p = .005). ConclusionWe identified two distinct CPA phenotypes, type-2 dominant and non-type-2, with different clinical and radiological findings and treatment outcomes. Future studies should confirm our findings and investigate different treatment strategies based on CPA phenotypes.

Automated summary

A study identified two distinct immunophenotypes of chronic pulmonary aspergillosis (CPA), with different clinical and treatment outcomes. Future research should validate these findings and explore different therapeutic strategies based on CPA phenotypes.