We found that, following an acute LPS challenge, (1) c-Fos expression in the PVN was similar between SLE and control mice, (2) plasma ACTH was not altered in SLE or control mice, (3) SLE mice had an increased plasma corticosterone whereas controls did not, and (4) brain and spleen TNF-α was increased in SLE mice compared to their vehicle-treated counterparts. This evidence concerns the gene FOS and systemic lupus erythematosus.