A study published in Cytokine investigated CD3+ CD20+ CD4- CD8- double–negative (DN) and CD3+ CD20+ CD4/CD8+ T in patients with chronic plaque-type moderate to severe psoriasis and found that patients’ CD20+ cells were upregulated, despite the use of immunomodulatory treatments, and patients with psoriasis also displayed diffuse microvascular damage.
The study’s lead author, Serena Fragiotta, MD, PhD, suggested that “Double negative T cells may play a role in the early phase of the psoriatic disease.” However, the report did highlight that expression of intraocular pro-inflammatory cytokines did not seem to be affected in patients with psoriasis.
Nineteen patients (19 eyes) and 19 healthy volunteers (19 eyes) were evaluated with the Psoriasis Area Severity Index (PASI) and the Dermatology life quality index (DLQI). On the same day, a blood sample was collected and analyzed with multiparametric flow cytometry. Patients with psoriasis had 73.9% greater expression of CD3+CD4+/CD8+CD20+CD56- T cells compared to controls (p < 0.001), however, the same relationship was not found in the DN T cells (-8.2%, p = 0.30).
Moreover, the psoriasis group displayed significantly different microvascular characteristics than the control group, including artero-venous ratio (p = 0.04), subfoveal choriocapillaris/Sattler’s layer (p < 0.001), and choroidal thickness (CT) (p < 0.001). Researchers also associated increased circulating levels of CD3+CD4+/CD8+CD20+CD56- T cells with thinning in both the subfoveal CT (p = 0.03), and Haller’s layer (p = 0.01). Contrary to the CD20+ T cells, the DN T cells had an inverse correlation with disease duration, DLQI score, and use of biologic drugs.
Ultimately, the data showed that CD20+ T cell subpopulations are overabundant even in psoriasis being treated with immunomodulatory therapies. The authors also concluded that endothelial damage caused by the microvascular effects of psoriasis could be a mainstream component in the development of disease-related complications. They took the similar levels of pro-inflammatory cytokines amongst the eyes of patients with psoriasis and the healthy controls to support this theory.