Ex Vivo Study of Leukocyte Responses in the Blood of Patients With Leptospirosis and ex Vivo Testing of a New Host-targeted Therapeutic Strategy to Restore Phagocytosis of Leptospira
Starting soon
Conditions studied: Leptospirosis, Jarisch Herxheimer Reaction
In brief
Leptospirosis is a neglected zoonosis caused by pathogenic spirochetes of the genus \*Leptospira\*, occurring mainly in humid tropical and subtropical regions. With over one million cases and \~60,000 deaths annually, it is among the most dangerous bacterial zoonoses worldwide. Its nonspecific onset-fever, headache, myalgia-mimics influenza, dengue, and other acute febrile illnesses, making diagnosis difficult. Delayed antibiotic treatment can lead to severe forms (in \~10% of cases) characterized by hemorrhage and multi-organ failure. In 2023, New Caledonia reported 152 cases, with 85% hospitalized and a 2.6% mortality rate. This study aims to characterize the human host response and improve patient management. \*Leptospira\* evades innate immunity, triggering a strong anti-inflammatory IL-10 response and potentially ineffective phagocytosis. However, the WHO-recommended β-lactam antibiotics induce a Jarisch-Herxheimer reaction (JHR)-an acute inflammatory response occurring within hours of treatment-in over 50% of patients (LEPJAR study, PMID:40986630), the impact of which on phagocytosis is unknown.The NEUTROLEPTO study will be conducted in New Caledonia (NC) in patients with or without leptospirosis. Clinical and biological data will be collected at the time of suspected infection and 3 hours after antibiotic administration. Specifically, immune responses will be assessed through cytokine profiling and blood cell phenotyping, as well as by transcriptome analysis of infected patients before and after antibiotic treatment.
Key facts
- Study ID
- NCT07611591
- Run by
- Institut Pasteur
- People needed
- 70
- Starts
- 2026-07-01
- Expected to finish
- 2029-07-01
- Last updated by the study team
- 2026-05-28
Who can join
Age: 18 and older. Sex: any. Healthy volunteers: not accepted.
You may qualify if…
- Be of legal age (18 years or older at the time of enrollment),
- Be capable of understanding and providing informed consent,
- Have received information and provided written consent,
- Be enrolled in a social security program.
- Be suspected of having leptospirosis
You may not qualify if…
- With a chronic inflammatory disease,
- Whose health condition is incompatible with additional blood draws totaling 40 ml,
- Receiving concomitant treatment with antibiotics and/or anti-inflammatory drugs, or undergoing medical treatment incompatible with the study's objectives,
- Pregnant or breastfeeding women.
- Hospitalized or having undergone surgery within the previous 7 days
Full record on ClinicalTrials.gov
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