A number of studies suggest that UV exposures at environmental levels suppress immune responses. Due to damage to the Langerhan cells in the epidermis by UVA, their capacity to modulate immune reaction is lost, and body is more prone to develop secondary infections (Clynesdale, 2001). There is damage to the entire complex of systems involved in immune reaction.
There is damage to the T-cell mediated immune reaction, following poor antigen presentation, reduced expression of interleukins, poor activation of complement system and decreased expression of various adhesion molecules. Due to an overall depression in immunity, there is proof of recurrence of herpes and other viral illnesses like HIV (Clynesdale, 2001, INCHEM, 1994). Severe skin infections can occur following skin burns due to the loss of protective action of skin following burns by the UVR. 3 Others
INCHEM 1994 report highlights the increased incidence of cataracts in exposed individuals. Beneficial effects of UVR (INCHEM, 1994) UVR is essential for Vitamin D metabolism. Vitamin D plays a pivotal role in calcium metabolism in the growing age as well as in adults. Thus severe bone diseases can occur, children may be more prone to fractures, and gait disturbances. In addition UVR has been linked to a reduced incidence of colorectal and other GI malignancies. People have used it to tan their bodies for ages.
Summary UVR is a form of electromagnetic radiation. The most damaging form is the UVB ( 240-280 nm wavelength). It has been linked to development of skin cancers, like melanoma, basal cell and squamous cell cancers, actinic changes, like photoageing, cataracts. UVR plays a vital role in calcium metabolism. Thus there is a need to counter the harmful effects by reducing the man made damage to the environment, liberal use of sunscreens and early diagnosis and treatment.
References
1 Revis DR Jr, Seagle MB. Skin, Anatomy. Updated on Feb 17, 2006 . retrieved on 12/02/2006, from http://www. emedicine. com/plastic/topic389. htm/ 2 Clydesdale GJ, Dandie G, Muller HK. Ultraviolet light induced injury: Immunological and inflammatory effects. Immunol Cell Biol, Vol 79(6). Dec 2001. 547-568. 3 Ultraviolet Radiation. Environmental Health Criteria 160, International Programme On Chemical Safety (2000) retrieved on 12/02. 2006 http://www. inchem. org/documents/ehc/ehc/ehc160. htm/