Helminthologists contributed to clarifying the evolutionary significance of neuron-mediated skin itching, which protects against infection by schistosomes.
Our skin not only protects the body from external influences but also plays a key role in the immune system. However, many details about how the skin performs this function remain unclear.
A new study published in the prestigious journal Nature Immunology shows that the human blood fluke Schistosoma mansoni can block the sensation of itching in mice by inhibiting specific nerve cells in the skin. These cells help trigger immune responses that protect the body from parasites. They do this by influencing certain immune cells, which then release inflammation-regulating molecules in the skin. This research uncovers a new way that skin nerve cells can contribute to parasite defense by communicating with the immune system.
Tomáš Macháček and Petr Horák from the Laboratory of Helminthology also contributed to the study. Their team maintains laboratory cycles of Trichobilharzia spp., bird schistosomes related to human blood flukes, which are the causative agents of cercarial dermatitis. The comparison of the "itchy" reaction of mice to human (mammalian) and bird parasites provided an important evolutionary context for understanding the significance of non-allergic skin itching. While bird species trigger itching and are eliminated by their host, mammalian species are better adapted to their hosts and can effectively "turn off" itching and the subsequent immune response to survive in the host.
The publication is available here:
https://www.nature.com/articles/s41590-024-01982-y