The APRIL and/or BAFF plasma levels are upregulated in many noninfectious 26, 68, 69, 70, 71, 72, 73, 74, 75, 76 and infectious diseases 32, 73, 77, 78, including malaria 36, 54 that are often accompanied by polyclonal B‐cell activation, hypergammaglobulinemia, autoimmune disorders and lymphopenia. The gene discussed is TNFSF13B; the disease is lymphopenia.