Photodynamic therapy stimulates IL-6 and IL-8 in responding patients with HPV infection associated or not with LSIL

Photodynamic Therapy (PDT) is a non-invasive treatment that has shown its usefulness in eliminating low grade squamous intraepithelial lesion (LSIL) and Human Papilloma Virus (HPV) infection. The response to PDT is variable, how patient´s immunology works during human PDT is unclear and therefore, the main of this work was to characterize the local immune response during treatment with PDT in patients with LSIL and / or persistent HPV infection. Two groups divided into Complete Response and Non Response patients to PDT, which were treated with a scheme of 12% δ-aminolevulinic acid (ALA), 2 irradiations 48 h apart at a total energy dose of 200 J/cm², their local immune response were analyzed by Cytometric Bead Array (CBA) and spectral Cytometry before and after each irradiation. Cytokine mostly expressed previously PDT was IL-8 in all groups. PDT stimulates the increase in IL-6 and IL-8 concentrations at 48 h, being greater in the group of responding patients as well as IL-6 and IL-10 proving the host immune stimulus to remit diagnosis. Complete Response group has a higher percentage of total CD45+ cells before treatment than Non Response. A decrement pattern of CD8+ were observed on Non Response group during treatment. An increase tendency was observed on CD14+ and HLADR-ABC+ cells in both response groups. PDT is able to stimulate immune response, being important to treatment effectiveness increasing innate immune cells and their activation, such as monocytes, cytotoxic lymphocytes. A multiple HPV infection could be related to a less expression of cytokines during PDT.