Open Access

Background Oral leukoplakia (OL) is an unfavorable oral disease often resistant to therapy. To this end, cold physical plasma technology was explored as a novel therapeutic agent in an experimental setup. Methods Biopsies with a diameter of 3 mm were obtained from non-diseased and OL tissues. Subsequently, cold atmospheric pressure plasma (CAP) exposure was performed ex vivo in the laboratory. After 20 h of incubation, biopsies were cryo-conserved, and tissue sections were quantified for lymphocyte infiltrates, discriminating between naïve and memory cytotoxic and T-helper cells. In addition, the secretion pattern related to inflammation was investigated in the tissue culture supernatants by quantifying 10 chemokines and cytokines. Results In CAP-treated OL tissue, significantly decreased overall lymphocyte numbers were observed. In addition, reduced levels were observed when discriminating for the T-cell subpopulations but did not reach statistical significance. Moreover, CAP treatment significantly reduced levels of C-X-C motif chemokine 10 (CXCL10) and granulocyte-macrophage colony-stimulating factor in the OL biopsies' supernatants. In idiopathically inflamed tissues, ex vivo CAP exposure reduced T-cells and CXCL10 as well but also led to markedly increased interleukin-1β secretion. Conclusion Our findings suggest CAP to have immuno-modulatory properties, which could be of therapeutic significance in the therapy of OL. Future studies should investigate the efficacy of CAP therapy in vivo in a larger cohort.