PROJECT SUMMARY/ABSTRACT – Resource Core 1: Human Biosamples Core Obtaining fresh, carefully phenotyped human samples is the most daunting logistical hurdle facing the Joint Biology Consortium (JBC) Research Community. The Human Biosamples Core overcomes this barrier with a “systems solution” that integrates existing resources at the Brigham and Women’s Hospital (BWH), Boston Children’s Hospital (BCH), and affiliated institutions with a bioinformatically-sophisticated team of personnel to support sample identification, patient recruitment, sample processing, data management, and statistical analysis. Unique strengths include an extraordinary range of patient samples, both pediatric and adult; core leadership with expertise in cutting-edge translational research, biobanking, and electronic health record (EHR) interrogation; bioinformatics and biostatistics; and access to healthy controls as well as patients with comparator diseases. This mission will be realized through two Specific Aims. Aim I helps JBC members identify and obtain relevant archived biosamples from 16 different established sources, ranging from >120,000 patients in the Mass General Brigham (MGB) Biobank to highly specialized collections from common and rare rheumatic diseases as well as relevant controls. Examples include registries of rheumatoid arthritis (BRASS), psoriatic arthritis (COPPAR), and systemic lupus erythematosus (SYLVER); juvenile-onset rheumatic disease biobanks at BCH and CARRA; checkpoint inhibitor-induced rheumatic diseases; and synovial tissue from the Amsterdam Arthritis Bank as well as local archives. Aim II provides targeted, prospective recruitment via the JBC Recruitment Core, through which a dedicated team identifies, contacts, consents, obtains, and processes samples from patients meeting JBC member specifications. Donors include >120,000 MGB Biobank patients, including >45,000 with genotype data, BWH and BCH rheumatology clinics, ongoing clinical trials, and other sources. Led by expert rheumatoid arthritis investigator and methodologist Dr. Elizabeth Karlson, supported by associate directors Dr. Jeffrey Sparks at BWH, Dr. Lauren Henderson at BCH, and Dr. Deepak Rao heading the BWH Human Immunology Center for sample processing, the Human Biosamples Core represents a unified biospecimen pipeline to accelerate hypothesis-driven research into inflammatory arthritis and related diseases for investigators across the multicenter JBC network.