Skin autofluorescence reflects individual seasonal UV exposure, skin photodamage and skin cancer development in organ transplant recipients.

IMPORTANCE: Ultraviolet radiation (UVR)-induced skin cancers varies among organ transplant recipients (OTRs). To improve individual risk assessment of skin cancer, objectively quantified skin photodamage is needed. OBJECTIVES: We measured personal UVR-exposure dose in OTRs and assessed the relation between individual UVR exposure, skin cancer and objectively measured photodamage in terms of skin autofluorescence, pigmentation, and black light-evaluated solar lentigines. MATERIALS AND METHODS: Danish OTRs with (n=15) and without a history of skin cancer (n=15) kept sun diaries from May to September and wore personal dosimeters recording time-stamped UVR doses in standard erythema doses (SED). Photodamage was quantified as skin autofluorescence with excitation at 370nm (F370) and 430nm (F430), skin pigmentation (pigment protection factor, PPF), and black light-evaluated solar lentigines. RESULTS: OTRs with skin cancer received a higher UVR dose than OTRs without skin cancer (median 116 SED vs. 67 SED, p=0.07) and UVR exposure doses were correlated with increased PPF (p=0.052) and F370 on the shoulder (F370shoulder) (p=0.04). We found that skin cancer was associated with F370shoulder (OR 10.53, CI 3.3-31,938; p=0.018) and time since transplantation (OR 1.34, CI 0.95-1.91, p=0.097). A cut-off at 7.2 arbitrary units, 89% of OTRs with skin cancer had F370shoulder values above 7.2 arbitrary units and F370shoulder was additionally related to patient age (p=0.09) and black light-evaluated solar lentigines (p=0.04). CONCLUSION: F370 autofluorescence indicates objectively measured photodamage and may be used for individual risk assessment of skin cancer development in OTRs.