CD8+ T cells in the blood of people with mild-to-moderate psoriasis are functionally impaired

CD8+ T cells, also known as cytotoxic T cells, have been shown to play a key role in plaque psoriasis. They infiltrate psoriasis-affected skin areas and produce various inflammatory messenger molecules, which send signals to skin immune cells that promote the formation of psoriasis patches. However, it remains unclear whether these cells contribute to the inflammation throughout the body seen in psoriasis.

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In this study, researchers from Lydia Becker Institute, University of Manchester, and St John’s Institute of Dermatology, King’s College London, examined how CD8+ T cells behave in the circulation of people with psoriasis. They analysed blood samples from seven individuals with mild-to-moderate psoriasis and eleven individuals with healthy skin recruited in the UK.

The team discovered that these people with psoriasis had fewer CD8+ memory T cells in the bloodstream compared to individuals with healthy skin. Additionally, CD8+ T cells in individuals with psoriasis demonstrated lower levels of CXCR3, a marker that helps cells travel to inflammatory sites, and higher levels of BTLA, a receptor that suppresses the immune system.

This study also pinpointed the reduced activation and impaired function of these cells in people with psoriasis, as measured by key markers such as IFNγ (a small immune signalling molecule), upon stimulation. Interestingly, the psoriasis disease severity was positively associated with CD8+ memory T cells that produce IFNγ. These results suggest that CD8+ T cells in the bloodstream of people with psoriasis had weaker migration to the skin, where they have less effective immune responses in the context of psoriasis.

These alterations in CD8+ T cells may influence how inflammation spreads throughout the body in individuals with psoriasis. More research is needed to understand how treatments impact these immune cell changes and explore how they are related to CD8+ T cells in psoriasis lesions. By shedding light on these changes in CD8+T cells in the blood in psoriasis, we hope to pave the way for a better understanding of the mechanisms of diseaseand future therapies.

The work was funded by the Psoriasis Association. The full paper is available to read online at: https://doi.org/10.3389/fimmu.2025.1585378

Written by Yiqiao Chen