Immunomonitoring of Circulating Immune Cells in Maxillofacial Surgery

Description of Knowledge in the Relevant

Field:

The immune response contributes to tissue repair processes following surgery. Regulatory T cells (Tregs) modulate inflammation and may play a role in enhancing postoperative repair.

In particular, Tregs are emerging as powerful modulators of the immune response in various contexts during reconstruction. Indeed, Tregs are involved in tissue regeneration, control the local inflammatory response, and promote effective tissue repair while limiting fibrosis.

This study aims to document variations in Treg levels in peripheral blood following reconstructive maxillofacial surgery using free flaps.

Description of the Study Population and

Rationale for Its Selection:

The study population consists of patients undergoing maxillofacial surgery for free-flap reconstruction as part of their treatment, from whom relevant clinical data (healing time, length of hospital stays) can be collected. This selection allows for the exploration of the association between circulating immunological parameters and postoperative outcomes.

Description of the research focuses:

The research focuses primarily on the quantification and characterization of circulating Tregs (CD4+ CD25+ FOXP3+) and their subpopulations, as well as other cellular compartments of the immune response. Analyses may also be performed on surgical waste (bone, muscle, drainage fluids) if it can be recovered for research purposes, using flow cytometry and, where appropriate, single-cell transcriptomics.

These analyses will help establish the immunological profile of tissue-resident Tregs and compare it to that of circulating Tregs.

Justification of the study duration:

The total planned duration is 8 months, consisting of a recruitment period (6 months) to enroll a sufficient number of participants to analyze the associations between immunological parameters and clinical criteria (length of hospital stay, wound healing), as well as the patient follow-up period (2 months).

Primary Outcome Measure:

Proportion of regulatory T cells (Tregs) among CD4 lymphocytes, measured by flow cytometry at different time points (preoperative, perioperative, and postoperative), and association with length of hospital stay (days).

Secondary Outcome Measures:

Kinetics of the increase in circulating Tregs over the course of blood draws (preoperative visit, perioperative period, postoperative follow-up during hospitalization). Associated clinical criteria: time to healing/closure of the surgical wound and time until the decision to discharge the patient from the hospital.

Risks and safety monitoring:

Non-interventional research is considered to pose no specific research-related risks. In this study, samples are collected during routine blood draws for clinical care, with the addition of a tube designated for analysis. The management of adverse events is governed by the safety monitoring procedures in effect within the context of clinical care. Non-interventional research involving human subjects poses no risk to patients. Adverse events observed in patients participating in the research are reported by the investigators in accordance with local safety monitoring protocols established as part of routine clinical care.

Data management Clinical data (age, sex, history of malnutrition, history of immunosuppression, history of systemic anticancer treatment, length of hospitalization, wound healing/closure, discharge decision) are collected by maxillofacial surgeons based on medical observations during hospitalization. Biological data (flow cytometry, any transcriptomic analyses) are collected by biologists in the immunology laboratory. Clinical and biological data, rendered non identifiable, will be recorded in a REDCap® type electronic data collection form (E-CRF) made available free of charge by APHP.

Inclusion criteria

• Age ≥ 18 years
• managed in the department of maxillofacial surgery (Pitié-Salpêtrière Hospital)
• Scheduled for surgery as part of treatment involving free flap reconstruction
• Informed about the study, with no objections, and having provided written consent for genetic testing

Exclusion criteria

• Pregnant or breastfeeding women
• Individuals under legal protective measures