Schizophrenia is a debilitating, costly, socially disruptive, life-threatening disease in which available treatments are largely palliative and empirical, and produce significant short- and long-term side effects. Therefore, a strong case can made for exploring alternative treatments with a rational basis for use in this disease. Considerable evidence indicates that autoimmune processes may be involved in some forms of schizophrenia, including altered risk of certain autoimmune diseases in patients and their relatives, shared epidemiological features, and apparent involvement of genes known to influence the immune response repertoire. Attempts to provide direct evidence for autoimmune processes have proven elusive, possibly due to the technical difficulty inherent in accessing autoantibodies with high affinity for brain cell-surface receptors. In view of this impasse, we argue for a well-designed trial in schizophrenia of immunosuppressive therapy, which is now the mainstay of therapy for many autoimmune diseases. Analysis of disease states in which immunosuppression has been effectively used over many decades provides guidelines necessary for a meaningful trial.