title: Mixed connective tissue disease: a disease entity?
abstract: OBJECTIVE
  To explicate whether mixed connective tissue disease (MCTD) is a distinct disease and evaluate the reliability of three different diagnostic criteria proposed by Sharp, Alarcon-Segovia and Kasukawa respectively.
  
  
  METHODS
  Clinical follow-up of 50 MCTD patients lasted 2-8 years (80% > 5 years). HLA-A, -B as well as -DR typing was performed by complemently dependent cytotocity assay. Autoantibody profile was detected by counterimmune electrophoresis (CIE).
  
  
  RESULTS
  Thirteen (26.0%) of the 50 MCTD patients subsequently developed other connective tissue disease (OCTD), including 7 systemic lupus erythematosis (SLE), and 6 progressive systemic scleroderma (PSS). Among 23 of the MCTD patients fulfilling Sharp's criteria, 1 (4.3%) developed PSS, but among 23 of the patients fulfilling Kasukawa's, not Sharp's, 7 (30.4%) developed OCTD and among 27 of the patients fulfilling Alarcon-Segovia's, not Sharp's, 12 (44.4%) developed OCTD. In the frequencies of DR4 and DR5, there were significant differences between patients fulfilling Sharp's (60.9%, 56.5%) and controls (24.3%, P < 0.005, RR = 4.7 and 21.4%, P < 0.005, RR = 4.6%), but there were no significant differences between the patients not fulfilling Sharp's and normal control (P > 0.05).
  
  
  CONCLUSIONS
  MCTD is a distict rheumatic disease. Sharp's criteria is the most reliable for diagnosis of MCTD.
authors.affiliation: Department of Rheumatology and Clinical Immunology, Renji Hospital, Shanghai Second Medical University, China.
authors.forename: N
authors.initials: N
authors.lastname: Shen
authors.forename: S
authors.initials: S
authors.lastname: Chen
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.forename: L
authors.initials: L
authors.lastname: Fan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D008947:Mixed Connective Tissue Disease / Q000175:diagnosis*; D012015:Reference Standards