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Autoimmune diseases are multifactorial and include environmental as well as genetic drivers. Although much progress has been made in understanding the nature of genetic underpinnings of autoimmune disease, by comparison much less is understood regarding how environmental factors interact with genetics in the development of autoimmunity and autoimmune disease. In this report, we utilize the (New Zealand black × New Zealand white [NZB × NZW]) F1 mouse model of systemic lupus erythematosus (SLE). Mercury is a xenobiotic that is environmentally ubiquitous and is epidemiologically linked with the development of autoimmunity. Among other attributes of human SLE, (NZB × NZW) F1 mice spontaneously develop autoimmune-mediated kidney disease. It has been previously shown that if (NZB × NZW) F1 mice are exposed to inorganic mercury (Hg2+), the development of autoimmunity, including autoimmune kidney pathology, is accelerated. We now show that in these mice, the development of kidney disease is correlated with a decreased percentage of marginal zone (MZ) B-cells in the spleen. In Hg2+-intoxicated mice, kidney disease is significantly augmented, and matched by a greater decrease in MZ B-cell splenic percentages than found in control mice. In Hg2+- intoxicated mice, the decrease in MZ B-cells appears to be linked to aberrant B-cell receptor signal strength in transitory 2 (T2) B-cells, developmental precursors of MZ B-cells. [ABSTRACT FROM AUTHOR]

Objectives: The Trp620 allotype of PTPN22 confers susceptibility to rheumatoid arthritis (RA) and certain other classical autoimmune diseases. There has been a report of other variants within the PTPN22 locus that alter risk of RA; protective haplotype '5', haplotype group '6-10' and susceptibility haplotype '4', suggesting the possibility of other PTPN22 variants involved in the pathogenesis of RA independent of R620W (rs2476601). Our aim was to further investigate this possibility. Methods: A total of 4,460 RA cases and 4,481 controls, all European, were analysed. Single nucleotide polymorphisms rs3789607, rs12144309, rs3811021 and rs12566340 were genotyped over New Zealand (NZ) and UK samples. Publicallyavailable Wellcome Trust Case Control Consortium (WTCCC) genotype data were used. Results: The protective effect of haplotype 5 was confirmed (rs3789607; (OR = 0.91, P = 0.016), and a second protective effect (possibly of haplotype 6) was observed (rs12144309; OR = 0.90, P = 0.021). The previously reported susceptibility effect of haplotype 4 was not replicated; instead a protective effect was observed (rs3811021; OR = 0.85, P = 1.4×10-5). Haplotypes defined by rs3789607, rs12144309 and rs3811021 coalesced with the major allele of rs12566340 within the adjacent BFK (Bcell lymphoma 2 (BCL2) family kin) gene. We, therefore, tested rs12566340 for association with RA conditional on rs2476601; there was no evidence for an independent effect at rs12566340 (P = 0.76). Similarly, there was no evidence for an independent effect at rs12566340 in type 1 diabetes (P = 0.85). Conclusions: We have no evidence for a common variant additional to rs2476601 within the PTPN22 locus that influences the risk of RA. Arg620Trp is almost certainly the single common causal variant. [ABSTRACT FROM AUTHOR]

Oestrogens contribute to the female preponderance of autoimmune diseases such as systemic lupus erythematosus (SLE). Environmental xenoestrogens superimposed upon endogenous pituitarygonadal axis may affect the development of autoimmunity. This study examined the effects of chronic exposure to xenoestrogens - o,p'-dichlorodiphenyltrichloroethane (DDT) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on disease activity in the New Zealand Black/New Zealand White F1 hybrid (B/W) mousemodel of SLE. Intact female mice had repeatedly received injections of DDT, TCDD or control vehicle since 6 weeks of age. Weight change, albuminuria, mortality, relevant immunological and histological parameters were assessed. DDT exposure markedly increased the incidence of albuminuria and reduced uterine weight but had no measured effects on immunity or mortality in this study. TCDD-exposed mice had significantly lower incidence of albuminuria, serum anti-DNA antibody and total IgG levels, and mortality compared to controls. Also, TCDD group had significantly lower thymic and splenic weights, decreased percentages of CD4+CD8+ thymocytes and splenic CD4+ T cells, increased percentage of splenic B220+sIgM+ B cells and higher serum interferon gamma concentration. Taken together, DDT exposure appeared to accelerate the development of albuminuria in lupus-prone mice. TCDD was immunosuppressive to murine SLE. Xenoestrogens may have compound- and tissue-specific effects that require further elucidation in future work. [ABSTRACT FROM AUTHOR]

Abstract: Regulatory T cells (Tregs) play an important role in protection against autoimmune disease and are also known to be potent inhibitors of anti-tumor immune responses. The New Zealand Black (NZB) mouse is a murine model for both autoimmune diseases, since high levels of autoantibodies are present, and human CLL, due to the expansion of malignant B-1 cells. In this study, we examined the functional role of CD4+CD25+ Foxp3+ Tregs in these different manifestations. Flow cytometric analysis showed increased levels of Tregs in NZB mice compared to healthy C57Bl/6 controls. Aged NZB mice that have developed a B-1 cell malignancy identified as IgM+CD5+, have the most pronounced increase in Tregs. Ex vivo treatment of splenocytes from NZB mice with IFN-α resulted in a decrease in the frequency of Tregs and malignant B-1 cells. In vivo treatment of both NZB and C57Bl/6 mice with poly (I:C), a potent inducer of IFN-α, also led to a decrease in the levels of Tregs and malignant B-1 cells (NZB only) while amplifying autoimmune manifestations. These results indicate that while high levels of Tregs found in NZB mice might suppress a more severe autoimmune disease, they may also contribute to the development of the B cell malignancy. [Copyright &y& Elsevier]