title: Abnormalities in peripheral B cell memory of patients with primary Sjögren's syndrome.
abstract: OBJECTIVE
  To delineate disturbances in peripheral B cell memory in primary Sjögren's syndrome (SS).
  
  
  METHODS
  Isotype-specific immunoglobulin (Ig) heavy-chain transcripts were analyzed in single-sorted CD19+,CD27- naive and CD19+,CD27+ memory B cells from patients with primary SS and normal healthy control subjects.
  
  
  RESULTS
  A significantly higher frequency of B cells expressing mu-, alpha-, and/or gamma-chain transcripts were found in patients with primary SS compared with controls (58.0% versus 14.3%; P < 0.0001). Notably, 30.5% of individual B cells (for primary SS, 38.7%; for controls, 12.7% [P < 0.0001]) simultaneously expressed transcripts for different Ig heavy-chain isotypes using identical V(H)-D-J(H) rearrangements. However, these cells lacked surface expression of more than one of the respective Ig heavy-chain isotypes as well as messenger RNA (mRNA) transcripts for 2 germinal center markers, activation-induced cytidine deaminase, and Bcl-6. In contrast with the findings in normal healthy controls, peripheral B cell memory in patients with primary SS was characterized by 1) circulating CD27+ B cells expressing heavily mutated Ig V(H) transcripts (mutational frequency 8.6% versus 4.3%; P < 0.0001), 2) significantly enhanced mutational frequencies of C mu transcripts (9.6% versus 2.5%; P < 0.0001), 3) a high proportion (61.2%) of CD27+ B cells expressing transcripts for multiple Ig heavy-chain isotypes, and 4) a CD27- memory-type B cell subpopulation expressing mutated C mu transcripts.
  
  
  CONCLUSIONS
  Altogether, both B cell hyperactivity and striking abnormalities in peripheral B cell memory are indicated at the single-cell mRNA level in patients with primary SS. Detection of multiple Ig heavy-chain transcripts in peripheral CD19+,CD27+ memory B cells of patients with SS may represent the abnormal retention of pre-switch mRNA transcripts in circulating post-switch B cells.
authors.affiliation: Department of Medicine/Outpatients' Department, Charité University Hospital, Berlin, Germany. arne.hansen@charite.de
authors.forename: Arne
authors.initials: A
authors.lastname: Hansen
authors.forename: Mirko
authors.initials: M
authors.lastname: Gosemann
authors.forename: Axel
authors.initials: A
authors.lastname: Pruss
authors.forename: Karin
authors.initials: K
authors.lastname: Reiter
authors.forename: Sarka
authors.initials: S
authors.lastname: Ruzickova
authors.forename: Peter E
authors.initials: PE
authors.lastname: Lipsky
authors.forename: Thomas
authors.initials: T
authors.lastname: Dörner
mesh_terms: D000328:Adult; D000368:Aged; D018941:Antigens, CD19 / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D001483:Base Sequence; D015415:Biomarkers; D022801:Complementarity Determining Regions / Q000235:genetics / Q000276:immunology; D003564:Cytidine Deaminase / Q000235:genetics; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics; D005092:Exonucleases / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000276:immunology; D007156:Immunologic Memory / Q000276:immunology*; D008297:Male; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000235:genetics; D051560:Proto-Oncogene Proteins c-bcl-6; D012333:RNA, Messenger / Q000032:analysis; D012859:Sjogren's Syndrome / Q000276:immunology* / Q000503:physiopathology*; D014157:Transcription Factors / Q000235:genetics; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000378:metabolism
chemical_list: D018941:Antigens, CD19; D015415:Biomarkers; D022801:Complementarity Determining Regions; D004268:DNA-Binding Proteins; D007143:Immunoglobulin Heavy Chains; D011518:Proto-Oncogene Proteins; D051560:Proto-Oncogene Proteins c-bcl-6; D012333:RNA, Messenger; D014157:Transcription Factors; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D005092:Exonucleases; D003564:Cytidine Deaminase