*Article* **Unconventional Therapy with IgY in a Psoriatic Mouse Model Targeting Gut Microbiome**

**Mihaela Surcel 1 , Adriana Munteanu 1,2 , Gheorghita Isvoranu 3 , Alef Ibram <sup>4</sup> , Constantin Caruntu 5 , Carolina Constantin 1,6 and Monica Neagu 1,2,6, \***


**Abstract:** Psoriasis has a multifactorial pathogenesis and recently it was shown that alterations in the skin and intestinal microbiome are involved in the pathogenesis of psoriasis. Therefore, microbiome restoration becomes a promising preventive/therapy strategy in psoriasis. In our pre-clinical study design using a mice model of induced psoriatic dermatitis (Ps) we have tested the proof-of-concept that IgY raised against pathological human bacteria resistant to antibiotics can alleviate psoriatic lesions and restore deregulated immune cell parameters. Besides clinical evaluation of the mice and histology of the developed psoriatic lesions, cellular immune parameters were monitored. Immune cells populations/subpopulations from peripheral blood and spleen cell suspensions that follow the clinical improvement were assessed using flow cytometry. We have quantified T lymphocytes (CD3ε + ) with T-helper (CD4 <sup>+</sup>CD8 <sup>−</sup>) and T-suppressor/cytotoxic (CD8a <sup>+</sup>CD4 <sup>−</sup>) subsets, B lymphocytes (CD3ε <sup>−</sup>CD19 + ) and NK cells (CD3ε <sup>−</sup>NK1.1 + ). Improved clinical evolution of the induced Ps along with the restoration of immune cells parameters were obtained when orally IgY was administered. We pin-point that IgY specific compound can be used as a possible pre-biotic-like alternative adjuvant in psoriasis.

**Keywords:** IgY; psoriatic dermatitis; imiquimod; inflammation; C57 BL/6 mice
