TOKYO, Sept. 1 -- Researchers in Japan have found that parasitic infection appears to ease the symptom of atopic dermatitis (AD), which may help to develop new treatment for the chronic disease that affects skin.

A research group led by Ishikawa Osamu, professor of Gunma University, disclosed that after sample laboratory rats with AD were infected by malarial parasite (MP), their symptom of AD got relieved along with a flare-up of MP infection, according to a press release issued by the university recently.

Meanwhile, the researchers uncovered that natural killer cells (NK cells), a type of lymphocyte and a component of innate immune system, inside the skin of the sample lab rats increased. If the NK cells of the lab rats were prevented from growing by using medicine, their symptom of AD, however, were found not reduced.

NK cells play a major role in the host-rejection of both tumors and virally infected cells.

In addition, the researchers injected the above-mentioned NK cells into another group of sample lab rats with AD, whose symptom, as a result, were also found improved.

This new discovery, the research group said, might boost development of new drugs for AD treatment if NK cells could be obtained by alternative ways other than infection.

AD, also known as atopic eczema or eczema, is a type of dermatitis, an inflammatory, relapsing, non-contagious and itchy skin disorder. The cause of AD is not known, but the disease seems to result from a combination of genetic (hereditary) and environmental factors.