Cell-mediated immunity in acute idiopathic optic neuritis and multiple sclerosis.

Lymphocyte transformation responses to phytohaemagglutinin, measles antigen and tuberculin and the absolute numbers of circulating T and SIg+ cells were determined in 16 patients with acute idiopathic optic neuritis (ON), 42 patients with multiple sclerosis (MS) and 78 healthy controls. Patients with acute ON showed impaired lymphocyte transformation responses in both autologous plasma and AB serum similar in extent to those seen in MS patients in relapse. They were not associated with a reduced total number of circulating T cells.