Histological examination in assessment of ultraviolet-induced suppression of contact hypersensitivity response.

The evaluation of contact hypersensitivity (CHS) reaction is one of the methods used in the assessment of the immune status of an organism after UV radiation. The aim of the study was to compare usefulness of visual scoring system and histological morphometry in the assessment of CHS response after exposure of humans to solar simulated radiation (SSR). The study included 140 healthy volunteers, 33 people were irradiated for 2 days, 34 - for 10 days and 33 - for 30 days with SSR. Forty non-irradiated individuals served as controls. All the volunteers were sensitized with diphenylocyclopropenone (DPCP) 24 h after final exposure. Statistical analysis comparing intensity of CHS reaction based on visual score between irradiated groups and non-irradiated group revealed no differences (p>0.05). We found a significant difference in epidermal thickness between healthy skin and irradiated groups (p<0.05) and a positive correlation between intensity of spongiosis and clinical score for CHS response at 3.2 DPCP site (p<0.000001). A negative correlation between time of irradiation and spongiosis score was revealed (R=-0.28; p<0.001). We conclude that histological examination of biopsies taken from one of the series of elicitation sites is a reliable and sensitive method in the evaluation of CHS response after UVR.