title: Developing a new clinical tool for diagnosing chronic Q fever: the Coxiella ELISPOT.
abstract: Definitively establishing a clinical diagnosis of chronic Q fever remains challenging, as the diagnostic performance of both conventional serological tests and PCR is limited. Given the importance of an early diagnosis of chronic Q fever, there is a need for a reliable diagnostic test. We developed an enzyme-linked immunospot assay to measure Coxiella burnetii (C. burnetii)-specific T-cell responses (Coxiella ELISPOT) to both phase I and phase II antigens and tested convalescent Q fever patients (without chronic disease, n = 9) and patients with an established diagnosis of chronic Q fever (n = 3). The Coxiella ELISPOT adequately identified convalescent Q fever patients from healthy controls by demonstrating C. burnetii-specific T-cell interferon-γ production to both phase I and phase II antigens. Compared to convalescent Q fever patients, chronic Q fever patients showed a distinct Coxiella ELISPOT profile characterized by a much higher spot count for both phase I and phase II (18-fold for phase II, 8-fold higher for phase I) and a consistent shift towards more phase I reactivity. The diagnostic potential of the Coxiella ELISPOT is promising and warrants further investigation.
authors: Department of Pulmonary Diseases, Diakonessenhuis Utrecht, Utrecht, The Netherlands. gjmlimonard@gmail.com
authors: Gijs J M
authors: GJ
authors: Limonard
authors: Steven F
authors: SF
authors: Thijsen
authors: Aik W
authors: AW
authors: Bossink
authors: Anita
authors: A
authors: Asscheman
authors: John J M
authors: JJ
authors: Bouwman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial; D019411:Clinical Laboratory Techniques / Q000379:methods*; D016997:Coxiella burnetii / Q000276:immunology; D058501:Enzyme-Linked Immunospot Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011778:Q Fever / Q000175:diagnosis*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D007371:Interferon-gamma