Psoriasis refers to a chronic inflammation of the skin. This non-contagious disease affects 2 to 3% of the French population. It is caused by a genetic predisposition, but primarily by a failure of the immune system. With an unpredictable progression, it can present an isolated flare-up and cause new lesions years later. Discover the mechanism associated with this relapse.
Psoriasis: Why does it recur?
Summary
Published on February 20, 2024, by Manon, Scientific Editor — 4 min of reading
Themes:
Is it possible to completely cure psoriasis?
The psoriasis manifests as a chronic inflammatory skin disease. This characteristic implies a progressive evolution of the disease, which can be managed but often it is not cured permanently. Thanks to contemporary therapies, it is conceivable to regress psoriasis plaques, leading to extended periods of remission.
The management of psoriasis requires a medical prescription. Generally, the prescription consists of creams or lotions applied locally to the affected area. For advanced stages, professionals recommend oral medications, combined with exposure to UV rays. Severe cases are treated with immunosuppressants to limit the action of the immune system.
Psoriasis relapse: what is the mechanism?
Researchers at Brigham and Women's Hospital (BWH) have shed light on the issue of psoriasis relapse, specifically the reappearance of plaques in the same locations. This study was conducted following the cessation of management with topical steroids. The density of T lymphocytes in clinically resolved psoriasis lesions was significantly higher than in non-lesional and healthy control skin, and was not significantly different from that of the lesions before treatment. This therefore suggests the possibility of a specific group of resident T lymphocytes, capable of reactivating psoriasis and causing the recurrence of skin lesions following therapy.
The study demonstrated that residual populations of T lymphocytes in psoriatic lesions actively expressed the mRNA of IL-17A and IL-22, two cytokines involved in the pathogenesis of psoriasis. These resident T cells would then be capable of resetting the disease after the resolution of skin lesions. The process unfolds as follows: after inflammation, a group of recalcitrant cells remains. This suggests that conventional therapies probably do not eradicate pathogenic T lymphocytes, but rather suppress the activity of these cells.
These are capable of surviving for a long time within the skin. The cessation of active therapy allows these T lymphocytes to reactivate. These critical pathogenic T lymphocytes would be activated by autologous antigens or those derived from commensals, potentially triggering the inflammatory cascade and causing new or recurrent psoriatic skin lesions.
Recurrence of Psoriasis: The Aggravating Factors.
Many factors tend to influence the progression of psoriasis.
Some ENT (Ear, Nose, and Throat) infections can potentially cause a recurrence after a few weeks of remission.
Theexcessive consumption of alcoholcontributes to the onset of psoriasis flare-ups in some patients, as does tobacco.
The stress.
Overweight complicates the monitoring of the disease.
Individuals suffering from psoriasis benefit from regularly caring for their skin to prevent dryness and irritation. They should favour products and materials that respect their skin type: gentle and superfatted soap, clothing made from natural fabrics, cream and moisturising balm, etc.
Source
MATOS T. R. & al. Clinically resolved psoriatic lesions contain psoriasis-specific IL-17–producing αβ T cell clones. The Journal of Clinical Investigation (2017).
