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SLE is associated with a deficiency in cluster of differentiation 247 (CD247, also known as CD3 zeta chain), a component of the T-cell receptor (TCR)–CD3 complex. A comprehensive analysis showed that in more than half of SLE patients tested CD247 expression was either attenuated or absent. Recent evidence suggests that these variations in expression profiles may be due, at least in part, to polymorphisms in the CD247 gene. Aberrant CD247 transcript variants displaying either spliced exon 7 or short 3′-untranslated region have been detected in SLE T cells, and a recent genome-wide association study reported the existence of new CD247 single-nucleotide polymorphisms in SLE patients. Here, we review these unique and significant features of defective CD247 observed in SLE. [ABSTRACT FROM AUTHOR]

The strong association of the HLA-B27 with AS was first discovered independently by groups in London and California in 1972 and has recently been confirmed beyond reasonable doubt by fine mapping in the latest and most sophisticated genome-wide association study (GWAS) published this July. Yet, despite nearly four decades of extensive research, the exact role that HLA-B27 plays in pathogenesis remains unknown. However, we believe that recent developments in three fields have allowed us to view this conundrum in a new light and to propose coherent theories of disease pathogenesis. These areas are as follows: (i) GWASs, (ii) studies of B27 biology and (iii) lessons from biologic therapies. In this review we will discuss these recent advances before discussing the current models of AS pathogenesis under investigation. [ABSTRACT FROM AUTHOR]

Objective. A large number of genes, including several not previously implicated in SLE susceptibility, have recently been identified or confirmed by genome-wide association studies (GWAS). In this study, we sought to replicate some of these results in Finnish SLE patients (n = 275) and control individuals (n = 356).Methods. We genotyped 32 single nucleotide polymorphisms (SNPs) in 12 of the best-supported GWAS-identified SLE genes and loci. We further investigated gene–gene interactions between the loci included in the study.Results. The strongest evidence of association was found at the IRF5-TNPO3 locus, with the most significant P-value being 2.0 × 10−7 and an odds ratio of 1.95 (95% CI 1.51, 2.50). Association between SLE and TNFAIP3, FAM167A-BLK, BANK1 and KIAA1542 was also confirmed, although at a lower significance level and contribution to individual risk. No significant association was found with 1q25.1, PXK, ATG5, ICA1, XKR6, LYN and SCUBE1. Furthermore, no significant gene–gene interactions were detected.Conclusion. Replication of previous GWAS findings across diverse populations is of importance to validate these associations and to get a better understanding of potential genetic heterogeneity between populations in SLE susceptibility. Our results attest the importance of B-cell receptor pathway and IFN signalling in SLE pathogenesis. [ABSTRACT FROM PUBLISHER]

Objectives. To determine whether increased levels of B-cell activating factor (BAFF) in patients with SLE are due to disease activity or genetic variations in the promoter region of the BAFF gene and BAFF gene expression.Methods. The case–control study included 101 SLE patients and 111 healthy controls. Five single nucleotide polymorphisms (SNPs) in the BAFF promoter region were investigated by melting point analysis: c.-2841 (T > C), c.-2704 (T > C), c.-2701 (A > T), c.-871 (C > T) and c.-514 (A > G). BAFF mRNA levels were determined by real-time PCR (BAFF-RQ) and serum BAFF (s-BAFF) levels were measured by ELISA. Independent predictors that might be correlated with increased s-BAFF in SLE patients were analysed by multivariate regression methods.Results. Although s-BAFF levels were increased in SLE patients (1.73 vs 0.98 ng/μl, P < 0.001), no specific BAFF genotype was found to associate with SLE. The different genotypes defined by the investigated SNPs were identified both in SLE patients and healthy controls with similar frequencies. No association was found between BAFF genotype and BAFF-RQ. s-BAFF was independent of other factors, correlated with CRP (β = 0.40, P < 0.001) and physician's visual analogue score (R = 0.21, P = 0.046) and inversely with haemoglobin (β = −0.32, P < 0.001) and IgA (β = −0.33, P = 0.001).Conclusions. Increased s-BAFF levels in SLE patients are associated with the acute-phase responses, CRP and haemoglobin, but probably not dependent on BAFF genotype or expression. This indicates that s-BAFF production occurs at sites of inflammation. [ABSTRACT FROM PUBLISHER]

Objectives. CD38 participates in lymphocyte ontogeny and function and may be involved in autoimmunity. Absence of CD38 accelerates development of non-obese diabetic (NOD) mice diabetes and anti-CD38 antibodies are good markers of human disease. Little is known regarding systemic autoimmunity. Active SLE patients have higher numbers of CD38+ T and B cells. CD38 is a candidate gene for the murine Lmb2 lupus locus. We aimed to investigate whether CD38 was involved in lupus development.Methods. We developed Cd38−/−-Faslpr/Faslpr mice and monitored them for development of a lupus-like disease through measurement of protein excretion in urine, histological assessment of the kidneys, quantification of circulating immunoglobulins and autoantibodies. We have also immunophenotyped 2- and 6-month old Cd38−/−-Faslpr/Faslpr mice.Results. We found that absence of CD38 accelerated disease development: female Cd38−/−-Faslpr/Faslpr mice presented severe proteinuria, GN, deposition of ICs in the renal medulla and increased amounts of circulating immunoglobulin G (IgG), although anti-dsDNA autoantibodies and RF were not significantly increased at disease onset. We have found that Cd38−/−-Faslpr/Faslpr male mice, similarly to other murine models of lupus, were able to control disease. Absence of CD38 in lpr mice altered differentiation of T cells and dendritic cells (DC).Conclusion. Although the role of CD38 in tolerance is still to be elucidated, we provide evidence that it may play an active role in the control of a murine lupus-like disease. [ABSTRACT FROM PUBLISHER]

Objectives. To investigate whether maintaining the chondrocyte’s native pericellular matrix prevents collagen-induced up-regulation of collagenase-3 (MMP-13) and whether integrin α1 (ITGα1) and/or discoidin domain receptor 2 (DDR2) modulate MMP-13 expression and which signalling pathway plays a role in collagen-stimulated MMP-13 expression.Methods. Goat articular chondrocytes and chondrons were cultured on collagen coatings. Small interfering RNA (siRNA) oligonucleotides targeted against ITGα1 and DDR2 were transfected into primary chondrocytes. Chemical inhibitors for mitogen-activated protein kinase kinase (MEK1) (PD98059), focal adhesion kinase (FAK) (FAK inhibitor 14), mitogen-activated protein kinase 8 (JNK) (SP600125) and protein kinase C (PKC) (PKC412), and a calcium chelator (BAPTA-AM) were used in cell cultures. Real-time PCR was performed to examine gene expression levels of MMP-13, ITGα1 and DDR2 and collagenolytic activity was determined by measuring the amount of hydroxyproline released in the culture medium.Results. Maintaining the chondrocyte’s native pericellular matrix prevented MMP-13 up-regulation and collagenolytic activity when the cells were cultured on a collagen coating. Silencing of ITGα1 and DDR2 reduced MMP-13 gene expression and collagenolytic activity by primary chondrocytes cultured on collagen. Incubation with the PKC inhibitor strongly reduced MMP-13 gene expression levels. Gene expression levels of MMP-13 were also decreased by chondrocytes incubated with the MEK, FAK or JNK inhibitor.Conclusion. Maintaining the native pericellular matrix of chondrocytes prevents collagen-induced up-regulation of MMP-13. Both ITGα1 and DDR2 modulate MMP-13 expression after direct contact between chondrocytes and collagen. PKC, FAK, MEK and JNK are involved in collagen-stimulated expression of MMP-13. [ABSTRACT FROM PUBLISHER]