Human photobiology

Associate Professor Diona Damian, Head

Associate Professor Diona Damian’s research centres on the role of skin immunity in preventing and treating skin cancers. The immune system is a key defence against skin cancer, but even brief exposures to ultraviolet (UV) A and UVB radiation in sunlight can profoundly suppress skin immunity. Professor Damian’s group is investigating ways of preventing UV-induced immunosuppression and reducing the risk of skin cancer.

Her work with human volunteers has found that nicotinamide (vitamin B3) is highly immune protective against UVB and also against UVA, which is less effectively filtered by sunscreens. Nicotinamide is protective in tablet or lotion form, and works by increasing the energy of skin cells so that they can better withstand UV irradiation. Nicotinamide is widely available, safe and inexpensive and has now shown effectiveness in reducing actinic keratoses (pre-cancers) in heavily sun-damaged individuals. Clinical trials are now being set up to test whether nicotinamide can prevent skin cancers in high-risk patients.

Professor Damian’s group is also investigating the immune effects of photodynamic therapy (PDT). PDT involves red light irradiation after application of a photosensitising cream, and is an alternative to surgery for the treatment of non-melanoma skin cancers. The group has recently shown that current PDT protocols profoundly suppress immunity in human skin. This immunosuppression may reduce the effectiveness of PDT by allowing recurrence of tumour cells that would otherwise be destroyed by the immune system. Studies are now underway to determine how this PDT-immunosuppression can be prevented or reversed, with the hope that this will lead to higher cure rates in the clinic. Preliminary results suggest that simply altering the rate of light delivery to the skin can completely prevent PDT’s immune suppressive effects.

The other focus of Professor Damian’s research is the use of topical immunotherapy with diphencyprone (DPCP) for extensive recurrent melanoma in the skin, which has already failed or cannot be treated with surgery or radiotherapy. DPCP is a non-invasive, inexpensive treatment which harnesses the skin’s immune responses to destroy melanoma cells. So far, most patients have shown at least partial response to DPCP, and 60% have had complete clearance of their extensive skin lesions.

The research team

  • Dr Devita Surjana, Master of Philosophy student
  • Dr Sula Thanos, Master of Philosophy student

Featured image

Biopsy specimen of human skin

Biopsy specimen of human skin, stained to show Langerhans cells (antigen presenting cells central to skin immunity).