Immunosuppressive effects of silicon phthalocyanine photodynamic therapy

Academic Article


  • The purpose of this study was to determine if silicon phthalocyanine 4 (Pc 4), a second-generation photosensitizer being evaluated for the photodynamic therapy (PDT) of solid tumors, was immunosuppressive. Mice treated with Pc 4 PDT 3 days before dinitrofluorobenzene sensitization showed significant suppression of their cell-mediated immune response when compared to mice that were not exposed to PDT. The response was dose dependent, required both Pc 4 and light and occurred at a skin site remote from that exposed to the laser. The immunosuppression could not be reversed by in vivo pretreatment of mice with antibodies to tumor necrosis factor-alpha or interleukin-10. These results provide evidence that induction of cell-mediated immunity is suppressed after Pc 4 PDT. Strategies that prevent PDT-mediated immunosuppression may therefore enhance the efficacy of this therapeutic modality.
  • Published In

    Digital Object Identifier (doi)

    Author List

  • Reddan JC; Anderson CY; Xu H; Hrabovsky S; Freye K; Fairchild R; Tubesing KA; Elmets CA
  • Start Page

  • 72
  • End Page

  • 77
  • Volume

  • 70
  • Issue

  • 1