Psoriasis associated with increased duodenum inflammation

The duodenum of patients with psoriasis is characterised by subclinical inflammation. In half of patients, the gut mucosa had an increased permeability. This study, which was awarded the best scientific poster, fits well into the discussion about the gut-skin axis and the importance of the microbiome in psoriasis and psoriatic arthritis (PsA).

Psoriasis has a known association with inflammatory bowel disease (IBD) in terms of comorbidity, with a similar clinical course and some overlap in genotype. Even patients with psoriasis who do not have IBD are more likely to suffer from gastrointestinal symptoms. Studies from the 1990s showed increased numbers of eosinophilic granulocytes and mast cells in the duodenal mucosa of patients with psoriasis. In ulcerative colitis, these 2 cell types are implicated in increased intestinal permeability. Therefore, Prof. Maria Lampinen (Uppsala University, Sweden) and colleagues aimed to investigate the role of these cell types in patients with psoriasis.

The current study included 18 patients with psoriasis and 15 healthy controls. None of the participants had any gastrointestinal diagnosis. Biopsy samples were collected both from the duodenum and from the sigmoid colon. No visible inflammation was observed in the intestine of the patients, nor did the pathologist see any signs of damage.

The expression of several types of immune cells was assessed with immunohistochemistry and flow cytometry. Interestingly, not only were increased numbers of eosinophils and mast cells found, but also increased numbers of proinflammatory macrophages and cytotoxic CD8-positive T cells, which had increased expression of the activation marker CD69. Eosinophils were also activated, with increased expression of CD66b, a marker for degranulation.

These results suggest that, even in the absence of apparent inflammation, the intestinal immune cells in patients with psoriasis have an increased potential for inflammatory responses.

1. Lampinen M. Subclinical inflammation in the duodenum with increased numbers of activated immune cells in patients with mild to moderate psoriasis. Poster P17, 6^th World Psoriasis & Psoriatic Arthritis Conference, 30 June–3 July 2021.

 

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Posted on 17 September 202120 September 2021