Thymocytes and macrophages can be involved in the generation and perpetuation of autoimmune disorders in many ways. Evidence continues to mount for their active role. Although a significant association seems likely, one should remember that B cells and complement-directed granulocyte destruction may be equally if not more important. Furthermore, a combination of processes is not precluded by any fundamental biological law. Appropriate and effective therapy requires acceptance of this concept and further studies should attempt to define the interrelationships of these processes and focus upon methodology to determine their relative roles in a given situation.