ESR1 and systemic lupus erythematosus: Together, these observations suggested that the basal levels of ERα mRNA and protein are relatively higher in splenic cells from lupus-prone (NZB × NZW) F1 females than the age and strain-matched males and IFN-α (or IFN-γ) treatment of splenic cells increases the steady-state levels of ERα mRNA and protein in both males and females.