Development of a Quantitative Antigen Assay to Detect Coccidioidal Chitinase-1 (CTS1) in Human Serum

Francisca J. Grill, Thomas E. Grys, Marie F. Grill, Alexa Roeder, Janis E. Blair, Douglas F. Lake

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Background: Coccidioidomycosis is often diagnosed with a collection of tests that rely on the patient's ability to mount an immune response to the fungus (antibody-based diagnostics), making diagnosis of this infection challenging. Here we present an antigen-based assay that detects and quantifies coccidioidal chitinase-1 (CTS1) in human serum. Methods: An inhibition-based enzyme-linked immunoassay (ELISA) was developed that utilizes a monoclonal antibody specific for coccidioidal CTS1. CTS1 was quantified in commercial antigen preparations using recombinant CTS1 as a standard. Sera from 192 individuals from an endemic area were tested, which included 78 patients (40.6%) with proven or probable coccidioidomycosis. Results: The quantity of CTS1 in diagnostic commercial antigen preparations from different suppliers varied. CTS1 antigenemia was detected in 87.2% of patients with proven or probable coccidioidomycosis. Specificity was determined to be 96.94% using serum from individuals who reside in the Phoenix, Arizona area who did not have coccidioidomycosis. Levels of CTS1 correlated with low-and high-Titer serology from patients with a coccidioidomycosis diagnosis. Conclusions: Since the CTS1 inhibition ELISA described in this report does not depend on the host immune response, it is a promising diagnostic tool to aid in diagnosis and disease monitoring of coccidioidomycosis.

Original languageEnglish (US)
Article numberofab344
JournalOpen Forum Infectious Diseases
Issue number7
StatePublished - Jul 2021


  • Valley fever
  • coccidioidomycosis
  • diagnostic

ASJC Scopus subject areas

  • Oncology
  • Infectious Diseases


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