Immune response after photodynamic therapy increases anti-cancer and anti-bacterial effects

Table 1 Milestone studies on effects of photodynamic therapy affecting the immune system

Immune components	Immunomodulatory effect of PDT	Ref.
Pro-inflammatory cytokines	Production of pro-inflammatory cytokines after PDT in vivo	[26]
Macrophages	First evidence of cytokine production by PDT-treated macrophages in vivo	[107]
Dendritic cells	DCs can efficiently phagocytose PDT-treated tumor cells in in vivo experiments. Immature DCs administered in combination with PDT produce effective antitumor response in vivo	[38,108]
NKs	Role of NKs in immune response after PDT, control of distant untreated tumors	[43]
Neutrophils	Evidences that neutrophils have a crucial role in the PDT response in vivo	[30,109]
Memory immunity	First demonstration that a specific antitumor memory immunity is induced after PDT: resistance to tumor rechallenge in animals cured by PDT	[110]
T lymphocytes, memory immunity	Essential role of host T lymphocytes in immune response after PDT: curative effect of PDT in immune-competent Balb/c mice, but not in immune-suppressed scid mice. Adoptive transfer of splenocytes from PDT-cured mice to scid mice confers resistance to tumor rechallenge	[8,111]
Treg	Evidences for the role of Treg in inhibiting the immune response after PDT	[77]
Patient lymphocytes	First demonstration that an antigen-specific immune response can be observed after PDT	[65]

PDT: Photodynamic therapy; DCs: Dendritic cells; NKs: Natural killer cells; Treg: T regulatory cells.