psoriasis

Chronic, recurring skin disease characterized by raised, red, scaly patches, on the scalp, elbows, knees, and elsewhere. Tar preparations, steroid creams, and ultraviolet light are used to treat it, and sometimes it disappears spontaneously. Psoriasis may be accompanied by a form of arthritis (inflammation of the joints). It affects 100 million people worldwide.

Psoriasis is believed to be an autoimmune disease, in which the body's immune system attacks cells in the skin as if they were invading pathogens. A psoriasis vaccine (PVAC), containing heat-killed bacteria that alter the body's immune response by disrupting the body's T-lymphocytes, was developed in New Zealand. Tests showed that half of those vaccinated underwent significant improvement in their condition.