Bserved. The exact nature of clonal expansion and its role in
Bserved. The exact nature of clonal expansion and its role in generation of specific, mutated antibodies in RA is not known. Somatic mutations and isotype switching in synovial B lymphocytes might suggest the antigen-driven process. This would be supported by the expression of recombination-activating genes 1 and 2 (Rag1 and Rag2). Objectives To calculate mutational frequencies of immunoglobulin heavy-chain transcripts in the single plasma cells generated from RA synovium. To analyze the frequency of isotype-switched plasma cells and Rag1 and Rag2 gene expression in inflamed RA synovial tissue. Methods Individual CD19+CD38+ plasma cells were isolated from digested synovium of two Caucasian RA patients using single-cell deposition. The cDNA from each single plasma cell was generated and a nested PCR specific for VH genes and Rag1 and Rag2 genes was performed. After sequencing, the VBASE database was used to assign VH, DH and JH gene segments and somatic mutations. Results Three different subsets of CD19+CD38+ plasma cells were detected. The first subset represents cells expressing only IgM transcripts (IgM+, 13.5 ), cells in the second subset expressed only IgG transcripts (IgG+, 48.7 ), and the cells in the third subset expressed both IgM and IgG mRNAs (IgM+IgG+, 37.8 ). All of these detected IgVH mRNAs contained mutated sequences, indicating their memory cell origin. Significant differences in mutational frequencies were found between the subsets (IgM+ plasma cells, 3.8 ; IgG+ plasma cells, 11.2 ; and IgM+IgG+ cells, 6.3 ). Interestingly, either Rag1 or Rag2 mRNA was observed in 83.3 of all analyzed CD19+CD38+ plasma cells, with the highest frequency in the IgM+IgG+ subset (71.4 ). Conclusions The population of CD19+CD38+ plasma cells differentially expressing mutated IgVH mRNAs and reinducing Rag1 and PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/27689333 Rag2 genes was observed in RA synovium. The IgM+IgG+ cells might represent cells switching from the IgM to the IgG isotype, and IgG+ plasma cells might correspond to post-switched cells producing high-affinity (auto)antibodies. The high mutational rate and reinduction of Rag genes suggest an antigen-driven process. Acknowledgement This work was supported by grant NK/7273-3 from the Ministry of Health in the Czech Republic.therapy, since it was also found in patients with recent onset RA who had not received RG7800 manufacturer immunosuppressive therapy prior to study inclusion. Serum transfer experiments showed the presence of inhibitory factors in sera from RA patients to PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/26437915 be one mechanism contributing to the diminished response of RA monocytes, since those sera were also able to inhibit T-cell-dependent TNF- production in healthy monocytes. Conclusion The suppressed response of peripheral blood monocytes from RA patients to preactivated T cells shows that they are not likely to contribute significantly to the excessive levels of TNF- that are associated with this disease. The inhibitory activity of sera from RA patients in the cell contact-dependent system suggests a counterregulatory mechanism in the systemic circulation that prevents excessive activation of circulating monocytes in this disease.121 The declining incidence of nonsteroidal antiinflammatory drug gastropathy in rheumatoid arthritis patients: rates and reasonsJ Fries, K Murtaugh, M Bennett, E Zatarain, B Lingala, B Bruce Department of Medicine, Stanford University School of Medicine, Stanford, California, USA Arthritis Res Ther 2003, 5(Suppl 3):121 (DOI 10.1186/ar922) Background Nonsteroidal.