Abstract: Objective To investigate the association of imbalance of Tc1 and Tc2 cells with chronic actinic dermatitis (CAD). Methods Immunohistochemistry (S-P method) was used to test the subgroups of infiltrating cells and the expression of receptors of interleukin-4 (IL-4), interleukin-10 (IL-10), interleukin-12 (IL-12) and interferon-γ (IFN-γ) in these cells of the eruptions from 28 patients with CAD and 7 normal controls. The serum levels of IL-4, IL-10, IL-12 and IFN-γ from 33 patients with CAD and 32 normal controls were tested by ELISA. Results The major infiltrating cells in the eruptions of patients with CAD were T cells, which were significantly more than B cells (P<0.001). Among these T cells, the predominant was Tc cells, which were significantly more than Th cells (P<0.001). In the ease of infiltrating cells, the expression of receptors of IL-12 and IFN-γ was significantly higher than that of receptors of IL-4 and IL—10 (P<0.001). The serum levels of IL-12 and IFN-γ in patients with CAD were significantly increased than those in the control group (both P<0.05). Conclusions These findings indicate the imbalance of Tc1 and Tc2 cells probably plays an important role in the etiology and pathogenesis of CAD.

Key words: Photosensitivity disorders, T lymphocytes, helper-inducer, T lymphocytes, eytotoxic, Interleukins, Interferon typeⅡ