During the past two decades, investigators have made great inroads in understanding markers of genetic predisposition to the development of rheumatic diseases. An important question that must be addressed by investigators and clinicians is whether this knowledge will ultimately benefit patients, either through genetic counseling or predictions for beneficial therapeutic intervention. This article discusses various disease mechanisms and modes of immunotherapy such as anti-CD4, major histocompatibility complex blockade, and T-cell receptor-based and determinant-induced responsiveness.