The Interplay Between Immunodeficiencies, Allergies, Immune Dysregulation, and Lymphoproliferation: EAACI 2025

NBORN errors of immunity (IEI) are rare conditions caused by genetic factors that impair the development or function of the immune system. Currently, 559 IEIs are recognised, and this number is expected to grow with advancements in genomic sequencing and molecular immunology. Although IEIs typically present with an unusual tendency for recurrent and/or severe infections, patients often experience other manifestations, including atopy, immune dysregulation, haematological manifestations, and an increased risk of cancer, which highlights the overlap between immunology, rheumatology, allergology, and haematology. Keeping faith with its dual vocation as a society of allergology and clinical immunology, the European Academy of Allergy and Clinical Immunology (EAACI) Congress 2025 made an effort to provide updates and educational content in the field of rare immunological diseases. Here, the authors review the most impactful presentations and their findings.