The Research On Light Biology Experiment And Pathogenesis About Chronic Actinic Dermatitis

[Objective] To take advantage of the high prevalence of chronic actinic dermatitis (CAD) in Yunnan province. To measure and analysis the difference of the minimal erythema dose, photopatch testing among CAD patients and normal individuals.To investigate the association of Interleukin-6(IL-6) and Tumor Necrosis Factor-a(TNF-a) with CAD.[Methods] The minimal erythema dose (MED) of21patients with CAD and40normal controls were measured by SUV1000type μltraviolet sim μlator. Photopatch test was performed on21patients with CAD and21normal controls with standard photopatch test kit, then they were irradiated by SS-03AB type ultraviolet phototherapy instrument. The μltraviolet A (5J/cm2) was used as the source of irradiation. The serum levels of IL-6, TNF-a of patients with CAD and normal controls were tested by ELISA. The data were analyzed with the spss17.0statistical software.[Res μlts]1,The MED-μltraviolet A (UVA) and MED-μltraviolet B (UVB) of patients with CAD were26.05J/cm2and28.32mJ/cm2respectively. In the normal controls, the UVA-MED and UVB-MED were50.06J/cm2and38.25mJ/cm2respectively. The UVA-MED and UVB-MED of patients with CAD were significantly less than that of normal controls (P<0.05). The UVA-MED and UVB-MED of normal control group were not significant differences between men and women.(P>0.05).2,The photopatch test res μlts showed that the positive rates were57.1%and47.6%in the CAD patients and the normal controls respectively. The most common photo allergens of CAD were fragrance mixture (31.25%), D-usnic acid (12.50%) and wood composites (12.50%). In the normal controls, fragrance mixture(23.08%), D-usnic acid (15.38%)and balsam of Peru(15.38%) were the most common photoallergens. The positive rates of the photopatch test in the CAD patients and the normal controls were no significant differences (P>0.05).3,The serum level of IL-6in patients with CAD and normal controls were0.953±0.198(pg/ml) and3.165±0.772(pg/ml) respectively. The level of IL-6in CAD group was significantly decreased than that of the control group(P<0.05). The level of TNF-a of two groups were no significant differences (P>0.05).[Conclusion]1,The ultraviolet A and μltraviolet B radiation may play important roles in the pathogenesis of CAD, which is more sensitive to UVA.2,The photopatch test show that positive reactions for a variety of allergens in CAD patients and healthy controls.3,The lower level of IL-6may play a roles in the pathogenesis of CAD.