Er: YAG laser assisted photodynamic therapy for the management of severe oral epithelial dysplasia with innate and adaptive immune responses.

Oral epithelial dysplasia (OED) in oral potentially malignant disorders (OPMDs) increases the risk of malignant transformation. However, the management of OED is not well defined. Photodynamic therapy (PDT) is a hypotoxic, highly selective and minimally-invasive operation which reduces morbidity and disfigurement greatly. Additionally, laser ablation guaranteed a better penetration for topical application of 5-aminolaevulinic acid (ALA)-PDT. Herein, we present a case of a large lesion of oral leukoplakia (OLK) in left tongue dorsum and lateral margin, pathologically manifested as severe epithelial dysplasia (SED). We firstly discussed the feasibility of Er: YAG laser assisted PDT for the treatment of SED in OPMDs. The patient achieved complete remission at 1 year follow-up. Downregulated number of p53 and Ki67 positive cells were observed in the tissues after Er: YAG laser assisted PDT. In addition, increased CD8+ positive cells infiltrated around the tissues and increased natural killer (NK) cells level were detected in the peripheral blood. In summary, Erbium:yttrium-aluminum-garnet (Er:YAG) laser assisted PDT is an effective and promising treatment for the management of SED in OPMDs with innate and adaptive immune responses.