Abstract
Inborn errors of immunity (IEI) are genetic defects that can affect both the innate and the adaptive immune system. Patients with IEI usually present with recurrent infections, but many also suffer from immune dysregulation, autoimmunity, and malignancies.Inborn errors of the immune system can cause defects in the development and selection of the B-cell receptor (BCR ) repertoire. Patients with IEI can have a defect in one of the key processes of immune repertoire formation like V(D)J recombination, somatic hypermutation (SHM), class switch recombination (CSR), or (pre-)BCR signalling and proliferation. However, also other genetic defects can lead to quantitative and qualitative differences in the immune repertoire.In this chapter, we will give an overview of protocols that can be used to study the immune repertoire in patients with IEI, provide considerations to take into account before setting up experiments, and discuss analysis of the immune repertoire data using Antigen Receptor Galaxy (ARGalaxy).