title: Isotype switching and titer variation of anti-Ro/SSA antibodies over time in 100 patients with undifferentiated connective tissue disease (UCTD).
abstract: OBJECTIVE
  To correlate the clinical course of the disease with the titer, the isotype profile and the switch of the anti-Ro/SSA antibodies in a cohort of patients affected by UCTD.
  
  
  METHODS
  One hundred selected patients with anti-Ro/SSA antibodies detected by counterimmunoelectrophoresis (CIE), and affected by UCTD with a mean follow-up of 7.6 years (SD 4.8 yrs.), were studied. The titer of IgA, IgG and IgM anti-Ro/SSA antibodies was determined in two different sera, obtained at the time of diagnosis and at the last visit, by ELISA with Ro/SSA recombinant proteins as substrate.
  
  
  RESULTS
  Thirty-five patients evolved from UCTD to a different connective tissue disease, while 65 showed a stable disease. Anti-Ro/SSA antibodies were detected in 91% and 97% of the patients, at baseline and during follow-up, respectively. IgG dominates the anti-Ro response. The titer of IgA, IgM and IgG anti-Ro/SSA did not differ significantly between the two groups of patients with UCTD. An increasing trend of IgG and IgA anti-Ro/SSA titer could be detected in patients evolving in primary Sjögren's Syndrome (pSS), but only the increase of IgG anti-Ro/SSA was significant (p=0.0235).
  
  
  CONCLUSIONS
  IgG dominates the anti-Ro/SSA response in patients with UCTD. No substantial change of the antibody isotype against Ro/SSA peptides could be observed during follow-up. The titer of IgG anti-Ro/SSA significantly raised in the group of patients evolving in pSS.
authors.affiliation: Rheumatology Unit and Chair, A.O. Spedali Civili di Brescia, Università degli Studi di Brescia, Brescia, Italy. dott.ceribelli@libero.it
authors.forename: A
authors.initials: A
authors.lastname: Ceribelli
authors.forename: I
authors.initials: I
authors.lastname: Cavazzana
authors.forename: F
authors.initials: F
authors.lastname: Franceschini
authors.forename: M
authors.initials: M
authors.lastname: Quinzanini
authors.forename: F Lodi
authors.initials: FL
authors.lastname: Rizzini
authors.forename: R
authors.initials: R
authors.lastname: Cattaneo
mesh_terms: D001323:Autoantibodies / Q000032:analysis*; D001324:Autoantigens / Q000276:immunology*; D003240:Connective Tissue Diseases / Q000276:immunology*; D003378:Counterimmunoelectrophoresis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D017578:Immunoglobulin Class Switching / Q000276:immunology*; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D008297:Male; D008875:Middle Aged; D020733:RNA, Small Cytoplasmic / Q000276:immunology*; D012261:Ribonucleoproteins / Q000276:immunology*; D012859:Sjogren's Syndrome / Q000276:immunology; D000099207:SS-A Antigen
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; C116006:RO60 protein, human; D000099207:SS-A Antigen