Email updates

Keep up to date with the latest news and content from Arthritis Research & Therapy and BioMed Central.

This article is part of the supplement: 24th European Workshop for Rheumatology Research

Meeting abstract

Two B cell populations differentially expressing IgVH mRNAs in human RA synovium

S Ruzickova1, O Krystufkova1, L Sedova1, J Niederlova1, Z Cimburek2, T Dörner3 and J Vencovsky1

Author Affiliations

1 Institute of Rheumatology and LGE, Prague, Czech Republic

2 Department of Immunology and Gnotobiology, CAS, Prague, Czech Republic

3 Department of Rheumatology, Charité, Berlin, Germany

For all author emails, please log on.

Arthritis Res Ther 2004, 6(Suppl 1):12  doi:10.1186/ar1054


The electronic version of this article is the complete one and can be found online at:


Received:16 January 2004
Published:24 February 2004

©

Background

The lymphocytic infiltrates sometimes organized in ectopic germinal centres in rheumatoid arthritis (RA) synovium contain locally activated B cells expressing hypermutated immunoglobulin transcripts and recombination-activating genes (Rag), suggesting an ongoing antigen driven process directly in synovium.

Objective

To test this hypothesis, mutational frequencies of immunoglobulin mRNAs, signs of isotype switching and Rag gene expression in individual RA synovial B cells were analyzed.

Methods

Single-cell RT-PCR was used to analyze individual synovial CD19+CD38+ and CD19+IgM+ B cells (as the reference population) from two RA patients.

Results

We found significantly reduced frequencies of peripheral blood CD19+CD38+ B cells from RA patients as compared with controls, suggesting their possible migration into the site of inflammation. Three subsets of CD19+CD38+ B cells in RA synovium were detected, expressing (1) only IgM transcripts (IgM+, 13.5%), (2) only IgG transcripts (IgG+, 48.7%), and (3) both IgM and IgG mRNAs (IgM+IgG+, 37.8%). The differences in mutational frequencies between them were significant (Table 1). Over 40% of analyzed cells coexpressed Rag mRNAs. Similar subsets and expression patterns were found in CD19+IgM+ B cells; however, IgG+ cells displayed significantly decreased mutational frequencies (3.6%; P < 0.0001). This might reflect the presence of synovial B cell populations that differ in their maturational status or biological function.

Table 1. Mutational frequencies of IgVH mRNAs in RA synovial CD19+CD38+ and CD19+IgM+ populations