Rationale for thymopentin as therapeutic agent in rheumatoid arthritis.

Etiology and pathogenesis of rheumatoid arthritis (RA) is reviewed, with special emphasis on immunological factors. A common feature in active RA seems to be the decreased T cell suppressor/cytotoxic response, also reflected in an increased OKT4/OKT8 ratio. As the presence of several subgroups in patients is possible, the therapeutic approach may differ accordingly. Different disease-modifying antirheumatic drugs (DMARDs) are discussed in this context; their most characteristic features are slow onset of action (i.e., after several months) and improvement in immunological parameters. Although thymopentin does possess the latter property, it is not considered a DMARD at the present time. The action of thymopentin sets in within a few weeks, and it is speculated whether this may be due to its possible hormonal effects (via beta-endorphins, prostaglandins, etc.).