Objective: The role of osteoprotegerin (OPG) and its receptor activator of nuclear factor kB legend (RANKL) in the regulation of bone in humans remain unclear. We examined the sex-specific associations of serum OPG, RANKL, and their ratio with bone mineral density (BMD) in older adults. Design: Participants were 681 community-dwelling adults, ages 45-90 years, who had serum OPG and RANKL measured and bone density scans in 1988-1991, with follow-up scans 5 and/or 10 years later. Methods: Analyses were sex-specific; women using and not using estrogen were evaluated separately. Cross-sectional analyses used multivariable regression models; longitudinal analyses used repeated measures mixed effects models. Results: In cross-sectional analyses, age-and weight-adjusted serum OPG levels were significantly positively associated with BMD at the lumbar spine in men, and at the femoral neck, total hip, and lumbar spine in women using estrogen, but not in non-users of estrogen. RANKL concentrations were significantly and inversely associated with BMD in men only, and at the total hip. Neither OPG nor RANKL was significantly associated with bone loss. Results for the RANKL/OPG ratio were the same as those for RANKL alone. Conclusions: These results suggest a modulatory effect of both endogenous and exogenous sex hormones on the biologic interaction of OPG, RANKL, and bone.European Journal of Endocrinology 156 555-562

Adding CLND to TT does not increase postoperative hypocalcemia or vocal cord paralysis. These results suggest that in the hands of experienced thyroid oncologic surgeons, elective selective CLND can be performed safely for papillary thyroid cancer and should be considered in higher-risk patients to potentially reduce the risk of reoperation in the central compartment.

Testosterone has profound immune-modulatory actions, which may be important for the sexual dimorphism in immune-related disorders, such as autoimmune diseases. A well-known effect of androgens is inhibition of bone marrow B lymphopoiesis; however, a plausible target cell for this effect has not yet been presented. The aim of this study was to determine the target cell for androgen-mediated regulation of bone marrow B lymphopoiesis in males. We confirm higher number of bone marrow B cells in male mice with global inactivation of the androgen receptor (AR) and these global AR knockout (G-ARKO) mice had increased number of B cell precursors from the pro-B stage. Because osteoblast-lineage cells are known to support B lymphopoiesis at the pro-B stage, we investigated the effect on B lymphopoiesis in osteoblast-lineage cell-specific ARKO (O-ARKO) mice; O-ARKO mice had increased number of B cells in the bone marrow, and the number of B cell precursors was increased from the pro-B stage, demonstrating that O-ARKO mimics the bone marrow B lymphopoiesis pattern of G-ARKO mice. By contrast, O-ARKO mice displayed only minor changes in B cell numbers in the splenic compartment compared with G-ARKO. Further, O-ARKO mice had moderately reduced number of bone trabeculae in the vertebrae, whereas cortical bone was unaffected. In conclusion, androgens exert inhibitory effects on bone marrow B lymphopoiesis in males by targeting the AR in osteoblast-lineage cells. The identification of the likely target cell for androgen-mediated regulation of bone marrow B lymphopoiesis will contribute to elucidation of the mechanisms by which androgens modulate immune-related disorders.

Food allergy represents failure to develop tolerance to dietary proteins. Food allergy has increased in prevalence in parallel with decreased exposure to microbes during infancy. In mice, neonatal peroral exposure to the strongly T cell stimulating superantigen staphylococcal enterotoxin A (SEA), enhances the capacity to develop oral tolerance to a novel antigen encountered in adult life. A population of antigen-presenting cells in the gut, the CD103+ dendritic cells (DCs), is thought to be involved in oral tolerance development, as they convert naïve T cells into FoxP3+ regulatory T cells (Treg). This function depends on their capacity to convert vitamin A to retinoic acid, carried out by the retinal aldehyde dehydrogenase (RALDH) enzyme. Here, newborn mice were treated with superantigen and DC function and tolerogenic capacity was examined at six weeks of age. We observed that, in mice fed superantigen neonatally, the CD11c+ DCs had increased expression of RALDH and in vitro more efficiently induced expression Foxp3 expression to stimulated T cells. Further, these mice showed an accumulation of FoxP3+ T cells in the small intestinal lamina propria and had a more Ag-specific FoxP3+ T cells after oral tolerance induction in vivo. Moreover, the improved oral tolerance, as shown by increased protection from food allergy, was eradicated if the Vitamin A metabolism was inhibited. These observations contribute to the understanding of how a strong immune stimulation during the neonatal period influences the maturation of the immune system and suggests that such stimulation may reduce the risk of later allergy development.

Here, we investigate induction of immunological tolerance by lentiviral based gene therapy in a mouse model of rheumatoid arthritis, collagen II-induced arthritis (CIA). Targeting the expression of the collagen type II (CII) to antigen presenting cells (APCs) induced antigen-specific tolerance, where only 5% of the mice developed arthritis as compared with 95% of the control mice. In the CII-tolerized mice, the proportion of Tregs as well as mRNA expression of SOCS1 (suppressors of cytokine signaling 1) increased at day 3 after CII immunization. Transfer of B cells or non-B cell APC, as well as T cells, from tolerized to naïve mice all mediated a certain degree of tolerance. Thus, sustainable tolerance is established very early during the course of arthritis and is mediated by both B and non-B cells as APCs. This novel approach for inducing tolerance to disease specific antigens can be used for studying tolerance mechanisms, not only in CIA but also in other autoimmune diseases.

Selection of the primary antibody repertoire takes place in pro-/pre-B cells, and subsequently in immature and transitional B cells. At the first checkpoint, μ heavy (μH) chains assemble with surrogate light (SL) chain into a precursor B-cell receptor. In mice lacking SL chain, μH chain selection is impaired, and serum autoantibody levels are elevated. However, whether the development of autoantibody-producing cells is due to an inability of the resultant B-cell receptors to induce central and/or peripheral B-cell tolerance or other factors is unknown. Here, we show that receptor editing is defective, and that a higher proportion of BM immature B cells are prone to undergoing apoptosis. Furthermore, transitional B cells are also more prone to undergoing apoptosis, with a stronger selection pressure to enter the follicular B-cell pool. Those that enter the marginal zone (MZ) B-cell pool escape selection and survive, possibly due to the B-lymphopenia and elevated levels of B-cell activating factor. Moreover, the MZ B cells are responsible for the elevated IgM anti-dsDNA antibody levels detected in these mice. Thus, the SL chain is required for central and peripheral B-cell tolerance and inhibits anti-DNA antibody production by MZ B cells.Keywords: Autoantibodies r Autoimmunity r Light chain recombination r Marginal zone B cells r Pre-BCR Additional supporting information may be found in the online version of this article at the publisher's web-site Introduction V(D)J recombination is a stochastic process that gives rise to a vast primary repertoire of B-cell receptors (BCRs), recognizing self (auto) and nonself antigens. To purge and control autoreactive B cells, several checkpoints are in place, in both central and peripheral lymphoid organs [1,2]. The main mechanism of central B-cell tolerance is receptor editing [3,4] and, as some autoreactivity remains among the cells that migrate to the periphery [5], they undergo further selection as transitional B cells in the spleen Correspondence: Prof. Inga-Lill Mårtensson e-mail: lill.martensson@rheuma.gu.se[6], mainly by clonal deletion. Extrinsic factors are also involved, for example, B lymphocyte activating factor (BAFF), also known as BLyS, a key factor that modulates survival of peripheral B cells [7]. Defective central and peripheral B-cell tolerance checkpoints, as well as elevated BAFF levels have all been associated with autoimmune diseases, for example, systemic lupus erythematosus and rheumatoid arthritis, and mouse models thereof, a hallmark of which is autoantibody production [8][9][10].Selection of the primary BCR repertoire takes place also at the pro-B to pre-B-cell transition based on antibody μ heavy (μH) * These authors contributed equally to this work. and κ germline configuration (GL) and λ2 germline transcripts (λ2 0 ) and λ1,2,3 rearrangements (RE). (E) Rag-1 and Rag-2 mRNA levels. Data are shown as mean ± SEM of three to five mice per group, and are from a single experiment representative of three independent experiments. p Values were determine...

BackgroundThe mechanisms underlying tolerance induction and maintenance in autoimmune arthritis remain elusive. In a mouse model of rheumatoid arthritis, collagen type II (CII)-induced arthritis, we explore the contribution of B cells to antigen-specific tolerance.MethodsTo generate expression of the CII-peptide specifically on B-cell major histocompatibility complex type II, lentiviral-based gene therapy including a B-cell-specific Igk promoter was used.ResultsPresentation of the CII-peptide on B cells significantly reduced the frequency and severity of arthritis as well as the serum levels of CII -specific IgG antibodies. Further, both frequency and suppressive function of regulatory T cells were increased in tolerized mice. Adoptive transfer of regulatory T cells from tolerized mice to naïve mice ameliorated the development of CII-induced arthritis.ConclusionOur data suggest that endogenous presentation of the CII-peptide on B cells is one of the key contributors to arthritis tolerance induction and maintenance.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-016-1037-7) contains supplementary material, which is available to authorized users.

CD23, the low affinity receptor for immunoglobulin E (IgE), has been proposed to play a critical role in the regulation of IgE production, based on altered IgE levels in CD23-deficient mice and transgenic mouse models, as well as in mouse strains with mutations in the CD23 gene, e.g. 129 substrains. Here, we have investigated a mouse line termed LxT1 that expresses reduced CD23 surface levels on B cells, and its influence on natural IgE production. Extensive phenotypic analysis showed that CD23 surface expression was reduced in LxT1 compared to the control, without affecting B cell development in general. This CD23low surface level in LxT1 mice is not as a result of reduced CD23 mRNA expression levels or intracellular accumulation, but linked to a recessive locus, a 129-derived region spanning 28 Mb on chromosome 8, which includes the CD23 gene. Sequence analysis confirmed five mutations within the CD23 coding region in LxT1 mice, the same as those present in New Zealand Black (NZB) and 129 mice. However, this CD23low phenotype was not observed in all 129 substrains despite carrying these same CD23 mutations in the coding region. Moreover, serum IgE levels in LxT1 mice are as low as those in the C57BL/6 (B6) strain, and much lower than those in 129 substrains. These data indicate that the CD23 surface level and serum IgE level are uncoupled and that neither is directly regulated by the mutations within the CD23 coding region. This study suggests that caution should be taken when interpreting the immunological data derived from mice with different genetic background, especially if the gene of interest is thought to influence CD23 surface expression or serum IgE level.