Inhaled IL-4 halts neuron destruction in MS models

The researchers headed by Frauke Zipp from University Hospital Mainz, Germany, say their findings could pave the way toward unconventional and much-needed treatment strategies to alleviate neuron injuries that stem from brain inflammation (Science Transl. Medicine: doi: 10.1126/scitranslmed.aao2304)

Most approaches for treating multiple sclerosis aim to reduce the numbers of inflammatory activated T lymphocytes that destroy the myelin insulatiuon around neurons that accelerate transmission of signal transmission. The researchers leveraged the fact that although T cells can contribute to the progression of autoimmune diseases like multiple sclerosis, they also help maintain normal tissue function in healthy people. Searching for a signal from T cells that might be beneficial for healing nerve damage, the researchers narrowed in on a cytokine named IL-4.

In mice with a disease that mimics several aspects of multiple sclerosis, IL-4 injections alleviated neuron damage and caused marked improvements in the treated animals’ walking abilities. Importantly, similar benefits occurred when IL-4 was administered through nasal inhalation. What’s more, IL-4 treatment didn’t alter immune activity in the mice, instead the signaling molecule prevented break down of the long, thread-like projections called axons that allow nerve cells to transmit signals. The researchers showed that the receptor for IL-4 was present on axons in samples from human patients with multiple sclerosis. According to the authors, further studies should investigate optimum IL-4 dosing in animal models and potential side effects before proceeding to clinical trials.