The AYLo study (AutoimmunitY and Loss of y - Investigating the Role of Hematopoietic Mutations and Mosaic Mutation in the Y Chromosome in Autoimmune Rheumatologic Diseases) aims to systematically investigate hematopoietic mutations, such as hematopoietic (mosaic) loss of the Y chromosome (mLOY), focusing on their underlying causes, pathophysiological significance, patterns of manifestation, and impact on disease progression in autoimmune, rheumatologic disorders. This research seeks to bridge existing knowledge gaps by exploring how such mutations influence immune homeostasis, cellular function, and susceptibility to inflammation-driven pathologies. Through the integration of advanced immunological profiling, the study aspires to uncover key mechanisms that drive the initiation, progression, and complications of autoimmune rheumatic diseases. These analyses will combine single nucleotide polymorphisms (SNP) arrays, multiplex assays, transcriptomics, and flow cytometry staining of peripheral blood mononuclear cells to delineate the interplay between hematopoietic mutations and immune dysregulation. A further objective is the development of a multimodal framework for disease-specific characterization, enabling precise mapping of mutation-driven phenotypes across diverse autoimmune conditions. This framework will incorporate clinical, molecular, and imaging data. Additionally, the AYLo study aims to explore the potential role of mLOY and other hematopoietic mutations as biomarkers for disease stratification, prognosis, and therapeutic response. The findings may open avenues for personalized treatment approaches, leveraging the molecular insights to inform targeted interventions and improve patient outcomes in autoimmune rheumatic disorders. By integrating translational and basic science approaches, this study has the potential to redefine current paradigms in autoimmune disease research and therapy.