title: Clinical and laboratory profiles of rhupus syndrome in a Chinese population: a single-centre study of 51 patients.
abstract: OBJECTIVE
  The objective of this paper is to clarify the demographic, clinical and serologic characteristics of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) overlap syndrome, known as 'rhupus syndrome'.
  
  
  METHODS
  Between 1995 and 2012, 51 patients were classified as having rhupus among 3733 consecutive SLE patients. Rhupus was defined as a condition involving an overlap of RA and SLE features meeting the respective criteria of the American College of Rheumatology. The clinical and laboratory parameters of patients with rhupus syndrome were compared with those of 230 RA patients and 120 unselected SLE patients.
  
  
  RESULTS
  The age at the onset of rhupus was significantly younger than that of RA (p < 0.05), but similar to that of SLE. The initial manifestation was arthritis in 84.3% (43/51) of rhupus patients. Symptoms of SLE manifested after an average of 9.2 years. SLE was the initial diagnosis in 7.8% (four of 51) of patients, whereas both diseases developed simultaneously in 7.8% of the patients. SLE-associated manifestations were mild in rhupus syndrome, particularly neurologic disorders. Haematopoietic involvement was the most prominent systemic manifestation in rhupus patients.
  
  
  CONCLUSIONS
  Rhupus syndrome constitutes a subgroup of patients with distinct demographic, clinical and immunological characteristics. RA typically presents first, and less-severe SLE-associated damage is apparent.
authors.affiliation: Department of Rheumatology and Immunology, People's Hospital, Peking University, Beijing, China.
authors.forename: T
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Rheumatology and Immunology, People's Hospital, Peking University, Beijing, China.
authors.forename: G
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Rheumatology and Immunology, People's Hospital, Peking University, Beijing, China murong@pkuph.edu.cn.
authors.forename: R
authors.initials: R
authors.lastname: Mu
authors.affiliation: Department of Rheumatology and Immunology, People's Hospital, Peking University, Beijing, China.
authors.forename: H
authors.initials: H
authors.lastname: Ye
authors.affiliation: No. 13 Division Hospital, Xinjiang Production and Construction Corps, Hami City, China.
authors.forename: W
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Rheumatology and Immunology, People's Hospital, Peking University, Beijing, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Li
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000175:diagnosis*; D044466:Asian People; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013577:Syndrome
keywords: Systemic lupus erythematosus; overlap; rheumatoid arthritis; rhupus