Iron pills may weaken immunity in rare bleeding disorder

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * For all three groups: * Adult patient diagnosed with HHT (meeting 3 or 4 Curaçao criteria). * Documented pathogenic mutation in one of the following genes: ENG, ACVRL1, or MADH4. * Patient enrolled in the CIROCO cohort. * Written informed consent freely given and signed by the patient. * Patient covered by a social security scheme or equivalent. * Routine biological follow-up for HHT performed within the 15 days preceding the inclusion visit (complete blood count, reticulocytes, ferritin, CRP, calcium, phosphorus). * Specific to Group 1: * Ferritin \> 25 µg/L * No iron supplementation (oral or intravenous) in the past 3 months * No red blood cell transfusion in the past 3 months * Specific to Group 2: * Ferritin \> 25 µg/L * Ongoing oral iron therapy, or at least one intravenous iron infusion, or at least one red blood cell transfusion within the past 3 months * Specific to Group 3: * Ferritin \< 25 µg/L * No iron supplementation (oral or intravenous) in the past 3 months * No red blood cell transfusion in the past 3 months Exclusion Criteria: * Patients with hemoglobin levels \< 90 g/L. * Patients with active cancer or recent cancer remission (\< 3 months) that may alter the immune profile. * Patients with an active infection or recent infection recovery (\< 3 months) that may alter the immune profile. * Patients with an autoimmune or autoinflammatory disease, either active or recently treated (\< 3 months), requiring immunosuppressive therapy and potentially altering the immune profile. * Pregnant, postpartum, or breastfeeding women. * Minors. * Individuals deprived of liberty by judicial or administrative decision. * Individuals undergoing psychiatric care. * Individuals admitted to a healthcare or social institution for reasons other than research participation. * Adults under legal protection (guardianship, curatorship). * Individuals participating in another interventional clinical trial with an exclusion period still in effect at the time of pre-inclusion.