The human microbiota corresponds to an extremely rich and varied set of microorganisms that colonize our various epitheliums from birth, including the intestine, lungs and skin, where they interact continuously with our immune system. Changes in microbial composition and function, termed dysbiosis, have been linked to alterations in immune responses and to disease development, such as psoriasis. Recent research has shown that the gut microbiota can condition the therapeutic response to checkpoint inhibitors and that fecal microbiota transplant overcomes resistance to these therapy, suggesting a direct role for the microbiota in the ability to shape a therapeutic immune response. Antibiotic exposure during the course of cancer therapy negatively correlates with patients' response to anti-PD-1 treatment response, thus highlighting the link between the enrichment of specific microbial taxa in intestines and the response to immunotherapy. This observation suggests that treatments capable of modulating microbial networks and promoting specific bacterial clades may modulate the host's immune response. Hence, beyond their expected effect in the targeted tissue, part of the therapeutic effect of drugs could rely on this mechanism. In psoriasis patients, observational studies suggest that gut microbiome is altered differently after the use of anti-IL17 or anti-IL23 biologic agents. Main objective: To determine the evolution of microbial composition of fecal samples issued to patients who responded to a biologic agent (IL-17 inhibitors, IL-23 inhibitors) and have stopped their treatment for 2 to 4 weeks before the index date, at baseline and 6 months or clinical relapse after treatment discontinuation Design of the study: Prospective french multicentre observational cohort study Population of study participants: Patients with psoriasis in remission after IL23i or IL17inhibitor treatments and who have stopped their medication for 2 to 4 weeks. Number of participants included: 50 adult patients considered in remission and have stopped for at least 2 weeks and a maximum of 4 weeks, one of the following biologic agent: secukinumab, ixekizumab, brodalumab, bimekizumab, guselkumab, tildrakizumab, or risankizumab
Study Type
OBSERVATIONAL
Enrollment
50
Stool samples are a collection of products derived from the human body that is not invasive in any way and samples not taken as part of usual care. Stool samples will be collected at home within 7 days of the visit M0, M3 and M6 and within 14 days of the visit M12 in an ethanol tube and in DNA/RNA shield, and transported at room temperature to Saint-Antoine Hospital (CRB SAT, AP-HP, Pr. SIMON ), samples will be aliquoted (3 aliquots per tubes) and stored at -80°C for a period of 5 years (renewable) At the end of the research, stool samples will be analysed using metagenomics sequencing. DNA extraction will be performed following the standards of the The International Human Microbiome Standards . DNA will be stored at -80°C.
Blood samples (serum, 15 ml) are an additional and minimal collection performed following a sample taken as part of usual care. Blood samples (serum) will be collected during the visit at M0, M3 (± 7 days), M6 (± 7 days) and M12 (± 7 days). In the hours following collection, the samples must be aliquoted and stored at -80°C in a secure place in the participating centre.
Microbial features
Microbial features (gene richness, species, functional modules) impacted by the discontinuation of the biologic agent after 6 months or the first occurrence of psoriasis clinical relapse.
Time frame: after 6 months of the baseline visit or the first occurrence of psoriasis clinical relapse after baseline visit
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