Scientific Letters
Vol. 18 No. 1 (2026): Mediterranean Journal of Hematology and Infectious Diseases
Immune Biomarker Signature in the Diagnostic Workup of Fever Without Source: A Pilot Study
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All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.
Published: February 28, 2026
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Fevers without an identified source (FWS) are frequent in all-aged patients, even in children, with subjects being often labeled as affected with ‘fever of unknown origin’ if fever lasts for more than one week.1 This definition was formally created by Petersdorf and Beeson in the early ‘60s through the evaluation of a case series of subjects displaying unexplained rise of temperature over 38.3°C on several occasions for more than 3 weeks.2 It is well-known that FWS might include infectious, non-infectious inflammatory, tumoral diseases, but also further complex types of disorders in which fever is a predominant feature.3 Furthermore, among undiagnosed cases of FWS, the mortality rate may be relevant, varying from 6.9 to 18.6% in some reported series.4 In particular, investigating children with FWS may be may be frustrating because of multiple protean causes of fever, and autoinflammatory disorders.5 Infectious diseases are still a substantial etiology of FWS, while non-infectious conditions may elude many common diagnostic approaches, requiring imaging studies and more specific immunological or genetic tests.6
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Citations
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Ethics Approval
The study was conducted in accordance with the Declaration of Helsinki. A formal approval from the Ethics Committee of our University was not obtained because the General Authorization for Processing Personal Data for Scientific Research Purposes (Authorization No. 9/2014) is not required for retrospective archival studies with ID codes that prevent direct tracing of subjects’ data.How to Cite
“Immune Biomarker Signature in the Diagnostic Workup of Fever Without Source: A Pilot Study” (2026) Mediterranean Journal of Hematology and Infectious Diseases, 18(1). doi:10.4084/MJHID.2026.030.
Copyright (c) 2026 Angela Maria Di Francesco, Giuliana Pasciuto, Laura Gerardino, Ludovico Luca Sicignano, Elena Verrecchia, Andrea Urbani, Donato Rigante, Raffaele Manna
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
