Osteoradionecrosis of Jaws

The immune response following facial reconstruction may help predict healing time and the date of discharge after maxillofacial surgery. Regulatory T cells (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. An early increase in circulating Tregs could serve as an indicator of a favorable reparative/regenerative response. Primary objective: To identify changes in the proportion of regulatory T cells (Tregs) among circulating immune cells between the preoperative and postoperative periods, and to assess its association with length of hospital stay. 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 its association with length of hospital stay (days). Study Design: monocentric, including a maximum of 60 patients; 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 Research Process: After verifying eligibility criteria, patients will be informed about the study during a clinical visit. Following a reflection period that the patient deems necessary to make a decision, their lack of objection and consent to genetic testing will be obtained. As part of the research, a 7 mL tube of ACD blood will be collected in addition to the routine blood samples during routine blood draws at the following visits: preoperative, perioperative (during surgery), and postoperative follow-ups (Day 2, Day 5, and Day 15). These tubes will then be analyzed in the Immunology Research Laboratory of Prof. Miyara and Dr. Bouaoud (CIMI, Pitié Salpêtrière) using flow cytometry (counting/assay of Tregs and subpopulations). During the operation, surgical waste (bone, muscle, drainage fluids) will also be collected for research purposes; it will be analyzed in the immunology research laboratory of Prof. Miyara and Dr. Bouaoud (CIMI, Pitié Salpêtrière) using flow cytometry and, in some cases, single-cell transcriptomics when the sample meets the necessary quality criteria (sufficient cell count, viability, etc.).