To investigate the clinical and serological features of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) overlap syndrome (Rhupus syndrome).
We retrospectively reviewed the medical records of 21 patients with Rhupus syndrome who were hospitalized at Department of Rheumatology and Immunology, People's Hospital of Xinjiang Uygur Autonomous Region between January 2010 and January 2018. We compared the joint involvement, autoantibodies and clinical manifestations of Rhupus syndrome with 81 cases of RA-alone and 51 cases of SLE-alone.
In 21 patients with Rhupus syndrome, there are 3 males and 18 females. Compared with the SLE-alone group, the patients with Rhupus syndrome were older [(49.43±11.66) 
Rhupus syndrome is an overlapping syndrome in which RA and SLE coexist. Most of the diseases occur in RA and the related manifestations of RA are more serious than those of SLE. The incidence of Rhupus syndrome may be related to the change of sex hormone levels.