Rheumatoid Arthritis: Proust A

Sellam J, Miceli-Richard C, Gottenberg JE, Proust A, Ittah M, Lavie F, Loiseau P, Mariette X. · Rhumatologie, INSERM U802, Hôpital Bicêtre, Assistance Publique des Hôpitaux de Paris, Université Paris-Sud, Le Kremlin Bicêtre, France. · Rheumatology (Oxford). · Pubmed #18296721 No free full text.

Abstract: OBJECTIVES: Inhibitor of differentiation 3 (Id3)-deficient mice show sicca symptoms, lymphocyte infiltration of exocrine glands and positive anti-Ro/SSA and anti-La/SSB antibodies, all hallmarks of primary Sjögren's syndrome (pSS). The impairment of Id3 in T cells and, possibly, in salivary glandular epithelial cells (SGECs) seems to be involved. This animal model prompted us to investigate the role of Id3 in human pSS. METHODS: Quantitative Id3 expression in peripheral T cells, cultured SGECs and in total minor salivary glands was assessed by RT-PCR in pSS patients and controls. After Id3 sequencing, we investigated two single nucleotide polymorphisms (SNPs) (c.313G>A and g.-156A>G) in a case-control study of 212 Caucasian pSS patients and 168 controls. RESULTS: Quantitative Id3 expression was not decreased in pSS patients nor in SGECs, in T cells or in minor salivary glands. As well, patients and controls did not differ in allele and genotype frequencies of Id3 SNPs (P = 0.67 and P = 0.71 for the c.313G>A and the g.-156A>G, respectively). Neither SNP was associated with a pattern of autoantibody secretion. CONCLUSION: Although the Id3-deficient mouse model represents an attractive model for human pSS, Id3 expression is not impaired in SGECs, peripheral T cells and in labial salivary glands in pSS patients and Id3-relevant SNPs do not give evidence of genetic predisposition in Caucasian pSS patients.

Sellam J, Miceli-Richard C, Gottenberg JE, Ittah M, Lavie F, Lacabaratz C, Gestermann N, Proust A, Lambotte O, Mariette X. · Service de Rhumatologie, Hôpital de Bicêtre, 78 rue du Général Leclerc, 94275 Le Kremlin Bicêtre, France. · Ann Rheum Dis. · Pubmed #17185325 No free full text.

Abstract: OBJECTIVE: To analyse B cell activating factor (BAFF) receptor (BAFF-R) expression on peripheral lymphocytes from patients with primary Sjögren's syndrome (pSS) and systemic lupus erythematosus (SLE). PATIENTS AND METHODS: Peripheral blood mononuclear cells from 20 patients with pSS, 19 patients with SLE and 15 controls were examined by flow cytometry to investigate BAFF-R mean fluorescence intensity (MFI) on lymphocytes. BAFF-R mRNA level from isolated blood B cells of nine patients with pSS and eight controls was assessed by real-time quantitative reverse transcription-PCR. BAFF serum level was determined by ELISA. RESULTS: In all subjects, BAFF-R was expressed on all naïve CD27- and memory CD27+ B-cells and was present on <0.5% of T cells. The expression of BAFF-R on B cells was significantly decreased in patients with pSS as compared with controls (MFI = 7.8 vs 10.6, p = 0.001), and was intermediate in patients with SLE (MFI = 9.5). Serum BAFF level was inversely correlated with BAFF-R MFI (p = 0.007), but not because of competition between endogenous BAFF (at observed concentrations in patients) and the monoclonal antibody (11C1) detecting BAFF-R. BAFF-R mRNA levels did not differ between patients with pSS and controls (p = 0.48). BAFF-R MFI decreased after overnight culture with recombinant human BAFF (from 32.5 to 25.4, p = 0.03). Contrary to the serum BAFF level, BAFF-R expression was correlated with extraglandular involvement in pSS and SLE Disease Activity Index. CONCLUSIONS: BAFF-R expression is reduced on peripheral B cells of patients with pSS and SLE. This down-regulation occurs through a post-transcriptional mechanism and could be the consequence of chronic increase in BAFF. BAFF-R levels on B cells could be a novel activity biomarker in autoimmune diseases.

Gottenberg JE, Sellam J, Ittah M, Lavie F, Proust A, Zouali H, Sordet C, Sibilia J, Kimberly RP, Mariette X, Miceli-Richard C. · Rhumatologie, INSERM E 109, Hôpital Bicêtre, Assistance Publique-Hôpitaux de Paris, Université Paris-Sud 11, Le Kremlin Bicêtre, France. · Arthritis Res Ther. · Pubmed #16507129 links to  free full text

Abstract: Polyclonal B cell activation might be related to pathogenic over-expression of B-cell-activating factor (BAFF) in primary Sjögren's syndrome (pSS) and other autoimmune diseases. We therefore investigated whether BAFF over-expression in pSS could be a primary, genetically determined event that leads to the disease. The complete BAFF gene was sequenced in Caucasian pSS patients and control individuals. The only single nucleotide polymorphism frequently observed, namely -871 T/C in the promoter region, was then genotyped in 162 French patients with pSS and 90 French control individuals. No significant differences in allele (T allele frequency: 49.7% in patients with pSS versus 50% in controls; P = 0.94) and genotype frequencies of BAFF polymorphism were detected between pSS patients and control individuals. BAFF gene polymorphism was not associated with a specific pattern of antibody secretion either. T allele carriers had significantly increased BAFF protein serum levels (mean values of 8.6 and 5.7 ng/ml in patients with TT and TC genotypes, respectively, versus 3.3 ng/ml in patients with CC genotype; P = 0.01), although no correlation was observed between BAFF polymorphism and mRNA level. In conclusion, BAFF gene polymorphism is neither involved in genetic predisposition to pSS nor associated with a specific pattern of antibody production.

Ittah M, Gottenberg JE, Proust A, Hachulla E, Puechal X, Loiseau P, Mariette X, Miceli-Richard C. · Service de Rhumatologie, Institut Pour la Santé et la Recherche Médicale E 109, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Le Kremlin Bicêtre, France. · Genes Immun. · Pubmed #15933742 No free full text.

Abstract: One-third of first-degree relatives of patients with primary Sjögren's syndrome (pSS) suffer from other autoimmune diseases, including type I diabetes, systemic lupus erythematosus and autoimmune thyroiditis. Recently, 1858 C/T polymorphism of PTPN22 gene was reported to predispose to these autoimmune diseases. We decided to investigate whether PTPN22 gene polymorphism was also involved in the genetic predisposition to pSS in a case-control study, including 183 patients with pSS and 172 healthy controls. No significant differences in allele (T allele frequency: 7.7% in patients with pSS vs 7.8% in controls, P=0.9) and genotype frequencies of PTPN22 polymorphism were detected between patients with pSS and controls. PTPN 22 gene polymorphism was not associated with a specific pattern of autoantibody secretion either. Thus, 1858 C/T polymorphism of PTPN22 gene is not involved in genetic predisposition to pSS.