No or reduced TACI membrane expressionImpaired NF-κB signalingImpaired IgA and IgG class switchingReduced response to TI-2 AgsB-cell lymphoproliferations, splenomegalyIncreased frequency of autoimmune diseasesLack of lupus-like symptoms. The gene discussed is NFKB1; the disease is systemic lupus erythematosus.