Immune status of patients with multiple sclerosis: Analysis of primary and established immune responses in 24 patients

Twenty-four patients with multiple sclerosis participating in a controlled, double-blind trial of 6-mercaptopurine (6-MP) and methotrexate (MTX) were evaluated for their immunocompetence and immune responsiveness, No significant differences between the drug group and the placebo group were found in any of the tests. All patients had delayed hypersensitivity to at least one of five established delayed hypersensitivity antigens, had normal in vitro lymphocyte responses to the nonspecific mitogen phytohemagglutinin M (PHA) and to the specific mitogenic antigens streptolysin 0 and stre ptokinase-stre ptodornase, and had normal levels and prevalence of antibody to mumps, rubeola, herpes simplex, and cytomegalovirus. However, 52% of 23 patients failed to develop delayed hypersensitivity responses to the antigen keyhole limpet hemocyanin (KLH) compared with 18% of 11 normal adults. The antibody response to KLH was delayed in the patientscompared with normal adults. Antibody responses to influenza vaccination were also diminished. The defect in the immune response correlated directly with the seventy of the multiple sclerosis. If an immune defect exists in multiple sclerosis, it may be in the initiation of specific immune responses.