Lymphocyte transformation test in sympathetic ophthalmitis and the Vogt-Koyanagi-Harada syndrome.

The lymphocyte transformation test (LTT) has been shown to be a reliable method of demonstrating the antigen of delayed-type allergic responses. The test is based upon the process of gradual enlargement, transformation into lymphoblasts, and mitotic activity of small mature lymphocytes in the peripheral blood which occurs when they come into contact with an antigen to which the organism has previously been sensitized (Pearman, Lycette, and Fitzgerald, I963; Marshall and Roberts, I963; Daniels, Ritzmann, and Levin, I968; Ling, I968). The mechanism of this blastic transformation appears to be identical with that of lymphocyte activation observed in the course of homograft rejection. Blastogenesis will not take place if no antigen has been added to the lymphocyte cultures, or if the donor organism has not been previously sensitized to the antigen tested.