Allogeneic Stem Cells for Mild to Moderate Alzheimer's

Inclusion Criteria: * Patient between 50 and 85 years old * AD diagnosis according to NIA-AA 2011 criteria at a mild to moderate stage : MMSE score between 14 and 26 (include) positive AD amyloid biomarker * CDR (clinical dementia rating) score ≥ 1 * Patient with no absolute contraindications for PET or MRI scans * Consent signed by the patient and study partner * presence of primary caregiver * Patient with social security coverage Exclusion Criteria: * Brain disease (other than AD) that may cause dementia * Presence of concomitant pathologies not permitting participation in the study * Concurrent participation in other research that may influence the testing of the A3D study * Carrier of a pacemaker, valve prosthesis or other internal magnetic or electronic system, history of neurosurgery or aneurysm surgery, presence of metal fragments in the eyes, brain or marrow, claustrophobia * PET scan performed in the previous year (research context) * History of cancer diagnosed within the last 5 years * Presence of \> 4 brain microbleeds, a single area of superficial siderosis, or evidence of previous macrohaemorrhage assessed by brain MRI scan * Regular use of corticosteroids or other steroidal anti-inflammatory drugs (e. g. prednisone) * Presence of an autoimmune disease (e. g. rheumatoid arthritis, systemic lupus erythematosus) with the exception of psoriasis * Pregnant or breastfeeding woman * Adults under guardianship or other legal protection, deprived of their liberty by judicial or administrative decision For patients who will participate in the optional adipose puncture (only carried out in the Toulouse center): Antithrombotic treatment and xylocaine allergy are prohibited.