Role of Serological Tests in the Diagnosis of Mold Infections

Abstract

Purpose of ReviewTo understand the role of antibody detection in the diagnosis of infections caused by filamentous fungi (molds). Rapid and accurate profiling of infection-causing fungal pathogens remains a significant challenge in modern health care. Classical fungal culture and serology continue to be relevant even though over the past few decades, antigen (biomarker) assays such as ELISA and lateral flow devices have been developed and validated.Recent FindingsThis article reviews the current antibody detection systems (serological tests) for the diagnosis of mold infections associated with pulmonary disease and introduces new developments. Classic and more recently developed serological techniques and their performance characteristics, including immunodiffusion, complement fixation, and ELISA.SummaryThe diseases covered are allergic bronchopulmonary aspergillosis, chronic pulmonary aspergillosis, invasive aspergillosis, mucormycosis, diseases caused by filamentous basidiomycetes, infection caused by Talaromyces marneffei and pythiosis. Serology remains a cornerstone for fungal diagnostic testing.

Seroprevalence of Aspergillus IgG and disease prevalence of chronic pulmonary aspergillosis in a country with intermediate burden of tuberculosis: a prospective observational study

“…Younger age meant a higher IgG level in multivariate analysis. It has been shown that the antibody to Aspergillus increases throughout childhood and maintained certain degree of response in adulthood [28]. Our study suggested that early exposure to Aspergillus in childhood or adolescence may cause the production of IgG, which may decrease gradually during ageing.…”

Algorithm-aided diagnosis of chronic pulmonary aspergillosis in low- and middle-income countries by use of a lateral flow device

“…Aspergillus-IgG serology using ELISA has been the mainstay of immunological evidence of Aspergillus spp. infection in CPA [11]. ELISA instruments are expensive and labor and resource intensive; diagnostic cutoffs vary by ethnicity and technologies used which renders this tool not suitable for resource-limited laboratory settings.…”

Diagnostic cut‐off value for Aspergillus fumigatus‐ and flavus‐specific IgG with clinical relevance in chronic pulmonary Aspergillus infection: A pilot study in Taiwan

“…Following the cut‐off value identified in this study, we had a lower positivity for A. fumigatus IgG than in previous investigations 22 . This difference might be due to: (a) not detecting the IgM level for Aspergillus via current ELISA methodology, which might lead to false negatives for patients with CPA; (b) infections with non‐fumigatus Aspergillus having less cross‐immunogenicity with A. fumigatus that might lead to lower A. fumigatus IgG levels; (c) Aspergillus ‐specific antibodies detected by current ELISA methods (ImmunoCAP) had lower sensitivity in the general population in Taiwan compared to other countries; (d) not enrolling patients with ABPA because of a limited sample size in our preliminary results; or (e) a study population that was not solely patients with a history of anti‐TB chemotherapy who might have higher Aspergillus IgG levels 23 with more patients infected with A. fumigatus among them 24 .…”