As we had also found that CD8+ T cells were profoundly diminished in 1C6 × Rag1−/− mice, and as substantial evidence exists that in certain contexts, CD8+ regulatory T cells (Treg) can suppress inflammation in MS and EAE (13), we wanted to rule out the possibility that exacerbated disease in 1C6 × Rag1−/− mice was due to a lack of a CD8+ Treg. Here, RAG1 is linked to myeloid sarcoma.