TNFSF4 and systemic lupus erythematosus: Given the prominent function of ICOS and IL-21 in germinal center formation56–58, and given the eQTL within the OX40L gene linked to SLE13, we postulate that NIK inhibition in the context of SLE will lower germinal center formation as a result of inhibition of OX40 signaling in TFH cells.