A Clinical Study to Map the HLA Genomic Region in the Greek Population

Inclusion Criteria: The study will include adult subjects (age ≥ 18) that: * possess a Greek social security number and are visiting hospitals/clinics, and/or other private laboratory institutions (incl. clinics and health care groups) as part of standard clinical practice in Greece, * are willing and able to provide written informed consent to participate in the study according to the study protocol. Exclusion Criteria: * Subjects not able to provide written informed consent (e.g. ICU patients, mental illness patients, lack of legal capacity). * Subjects who have had an allogeneic (non-self-donor): * bone marrow transplant * stem cell transplant * blood transfusion less than two weeks prior to buccal swab sample collection * liver transplant * Subjects who participated in an interventional clinical trial in the past that according to the subject's physician opinion might have had an impact on their HLA genome.