The etiology of rheumatoid arthritis

The etiology of rheumatoid arthritis has been elusive, but it finally seems to be explained by a combination of three factors: (i) a relatively mild deficiency of cortisol, the normal adrenocortical hormone that is essential for normal immunity but which has achieved a bad reputation because of the use of excessive dosages of it or its stronger derivatives, (ii) a deficiency of dehydro-epi-androsterone (DHEA), the chief androgen produced by the human adrenal cortex but which has been little studied, and (iii) infection by organisms such as mycoplasma, which have a relatively low virulence, are difficult to culture in the laboratory, and cause inflammation and destruction of tissue in periarticular and articular areas of immunocompromised hosts. The mild adrenocortical deficiency apparently is sufficient to impair immunity, especially after stress, and permit these organisms to cause inflammatory arthritis. Further studies are necessary to determine optimum therapy, but it will probably include safe physiologic dosages of cortisol and DHEA plus antibiotic treatment of infection by mycoplasma or other causative organisms.