Sophie et al. found that a nanobody-based selective inhibitor of human TNFR1, TROS, was able to effectively delay disease onset, ameliorate symptoms, and prevent further disease development in a murine model of MS, in which the researchers generated mice expressing human TNFR1 in a mouse TNFR1-knockout background. Here, TNFRSF1A is linked to myeloid sarcoma.