The present invention provides compositions, systems, and methods for identifying a patient suffering from and/or susceptible to autoimmune disease who might be likely to respond to treatment with CXCL12 and/or CXCR4 antagonists. The present invention provides novel CXCL12 and/or CXCR4 antagonists, methods of identifying novel CXCL12 and/or CXCR4 antagonists, and methods involving the use of these in the treatment of autoimmune disease.