We aim to identify genetic determinants that account for variations in the immune response in different people. The work is focused on B cells because these are the cells that, when activated, produce the antibodies that are used to attack infectious organisms. Individuals with hypersensitive B-cell responses may be prone to autoimmune diseases. The clinical significance includes examining these specific genetic variants in children with autoimmune diseases. This approach could help identify children at risk for autoimmune diseases and could lead to changes in the therapies used to treat autoimmune diseases.