In the 1890s, sir William Osler, a famed American physician, observed that systemic LE could affect internal organs without the occurrence of skin changes. In 1948, Dr. Malcolm Hargraves of the Mayo Clinic described the LE cell, a particular cell found in the blood of patients with SLE. His discovery has enabled physicians to identify many more cases of LE by using a simple blood test. As a result, during the succeeding years the number of SLE cases diagnosed has steadily risen. Since 1954, various unusual proteins (antibodies) that act against the patient's own tissues have been found to be associated with SLE. Detection of these abnormal proteins has been used to develop more sensitive tests for systemic LE (anti nuclear antibody test). The presence of these antibodies may be the result of factors other than SLE.