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
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: 24 ml blood sample at H0, 16 ml blood sample at H3.
- Who it may be relevant to
- Registry conditions: Leptospirosis, Jarisch Herxheimer Reaction. Basic parameters: from 18 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Center list to be confirmed — check the primary protocol.
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
Unsure about the terms? Read our patient guide →
Overview
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.
Detailed description
The aim of the study is to compare the immune cell responses in the blood of patients hospitalized for leptospirosis with those of patients with another infection, before and 3 hours after antibiotic therapy.
Individuals presenting to the emergency department of the Territorial Hospital Center of New Caledonia with signs and symptoms of leptospirosis will be recruited:
-with a confirmed diagnosis of leptospirosis (Group 1),-
-with an infectious diagnosis other than leptospirosis (Group 2)
Blood and clinical data will be collected from all the participants.
Interventions
- Other 24 ml blood sample at H0
24 ml blood sample at H0 - Other 16 ml blood sample at H3
16 ml blood sample at H3
Primary outcome measures
- to compare the immune cell responses in the blood of patients hospitalized for leptospirosis with those of patients with another acute infection (MFA), both before and 3 hours after antibiotic treatment. [Time frame: 3 years]
Secondary outcome measures (2)
- Test certain innovative host-based strategies aimed at restoring phagocytic responses against Leptospira in the blood of patients with leptospirosis.response. [Time frame: 3 years]
- Describe and characterise the Leptospira spp. strain [Time frame: 3 years]
Eligibility criteria
Inclusion criteria
- 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
Exclusion criteria
- 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
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Observational model
- Case-control
Study locations
Center list to be confirmed — check the primary protocol.
Identifiers
NCT: NCT07611591 · 2025-146 · 2025-A02688-41