5-Aminolevulinic acid photodynamic therapy stimulates local immunity in patients with condylomata acuminata via activation of T lymphocytes.

OBJECTIVE: 5-Aminolevulinic acid photodynamic therapy (5-ALA-PDT) for condylomata acuminate (CA) is effective and safe, but how this treatment affects immune reaction is poorly understood. We aimed to explore the effects of PDT on local immunity in CA.

PATIENTS AND METHODS: Immunohistochemical analysis before and after PDT was performed to analyze local changes in the distribution of T lymphocytes, CD123+ plasmacytoid dendritic cells (pDCs) and CD1a+ myeloid DCs. Quantitative Real-time PCR (qRT-PCR) was used to detect changes in mRNA levels of interferon (IFN), ISG-15, Mx-2, TLR9, and IRF7.

RESULTS: Compared to the healthy foreskin, tissue from patient showed increased CD3+ and CD8+ cells but no significant changes in CD4+ cells or CD123+ pDCs, and a significantly decreased CD1a+ Langerhans cells (LCs). Twenty-four hours after a PDT session, local CD3+, CD4+, and CD123+ pDCs in lesions significantly increased and migrated to the superficial dermis. CD1a+ LCs in the epidermis gradually decreased, while DCs gradually increased. The number, distribution, and morphology of CD8+ cells did not change after a PDT session. The mRNA expressions of IFN-γ, IFN-α, IFN-β, ISG-15, Mx-2, TLR9, and IRF7 were all elevated. As compared to the patients without significantly increased IFN-a and IFN-b after a PDT session, patients with significant increases needed fewer sessions of PDT for a cure.

CONCLUSIONS: These results suggest that PDT for CA can activate T-lymphocyte-meditated immunity, and pDC-related immunity is also activated. The clinical efficacy of 5-ALA-PDT against CA may be related to the increased IFN-α and IFN-β after treatment.