LTBR and immune system disorder: The impact of lymphotoxin signaling and non-canonical NF-κB pathway has been well established in murine models (4, 8, 9, 11, 13, 15, 16), and its clinical relevance has recently been underscored in human immunity by the identification of inherited deficiencies in LTβR and NIK (17, 18), both of which recapitulate the immune disorder including the complete lymph node aplasia observed in their murine counterparts.