TNFRSF13B (Tumour Necrosis Factor Receptor Superfamily Member 13B): TNFRSF13B, also known as TACI, is a receptor for the cytokines BAFF and APRIL. Both play key roles in B cell development and function. Mutations in TNFRSF13B have been linked to common variable immunodeficiency (CVID) and selective IgA deficiency, highlighting its importance in humoral immunity. Research on TNFRSF13B focuses on understanding its role in immune dysregulation and autoimmune diseases.