Human autoantibody silencing by immunoglobulin light chains

Several newly arising human antibodies are polyreactive, but in normal individuals the majority of these potentially autodestructive antibodies are removed from the repertoire by receptor editing or B cell deletion in the bone marrow. To determine what proportion of naturally arising autoantibodies can be silenced by immunoglobulin (Ig) light chain receptor editing, we replaced the light chains in 12 such antibodies with a panel of representative Igkappa and Iglambda chains. We found that most naturally arising autoantibodies are readily silenced by light chain exchange. Thus, receptor editing may account for most autoreactive antibody silencing in humans. Light chain complementarity determining region (CDR) isoelectric points did not correlate with silencing activity, but Iglambda genes were more effective than Igkappa genes as silencers. The greater efficacy of Iglambda chains as silencer of autoreactivity provides a possible explanation for the expansion and altered configuration of the Iglambda locus in evolution.     

Bruton's tyrosine kinase is essential for human B cell tolerance

Most polyreactive and antinuclear antibodies are removed from the human antibody repertoire during B cell development. To elucidate how B cell receptor (BCR) signaling may regulate human B cell tolerance, we tested the specificity of recombinant antibodies from single peripheral B cells isolated from patients suffering from X-linked agammaglobulinemia (XLA). These patients carry mutations in the Bruton's tyrosine kinase (BTK) gene that encode an essential BCR signaling component. We find that in the absence of Btk, peripheral B cells show a distinct antibody repertoire consistent with extensive secondary V(D)J recombination. Nevertheless, XLA B cells are enriched in autoreactive clones. Our results demonstrate that Btk is essential in regulating thresholds for human B cell tolerance.     

An integrated appraisement of multiple faecal indicator bacteria and sterols in the detection of sewage contamination in subtropical tidal creeks

The quality of water bodies has been regulated by national environmental agencies and based on faecal indicator bacteria, such as thermotolerant coliforms Escherichia coli and Enterococcus sp. Additionally, faecal sterols (mainly coprostanol) have been used to corroborate sewage discharge in marine environments. In this study, faecal material input was evaluated in two sampling campaigns in transects of two tidal creeks using bacterial and chemical indicators to both compare and establish the water quality in a South Atlantic subtropical estuary. The Itiberê tidal creek (S1) was classified as “contaminated” by faecal material, while the Peças tidal creek (S2) presented variable water quality according to the sampling period and sewage indicators considered in this evaluation. Then, the integrated application of chemical and bacterial indicators was applied for tidal creeks with different sewage contamination levels and under distinct environmental conditions and confirmed that Enterococcus sp. and coprostanol are the most suitable for estuarine environments.     

Results of preoperative chemoradiotherapy for patients with advanced cancer of the nasal cavity and paranasal sinuses

Objectives: Curative treatment of nasal cavity and paranasal sinus cancer is challenging due to the proximity to critical anatomical structures. The purpose of this study was to analyze the impact of trimodality therapy with preoperative chemotherapy and reduced-dose radiotherapy followed by organ-preserving surgery for treating patients with nasal cavity and paranasal sinus cancer.

Methods: This retrospective study included all 156 patients diagnosed with sinonasal cancer in western Sweden between 1986 and 2009. We determined the treatment selection pattern and treatment outcomes for 79 patients treated with preoperative chemoradiotherapy.

Results: Squamous cell carcinoma was the most common histology. The five-year overall survival was 54%, and 85% of these patients had T3 or T4 tumors. The five-year cumulative incidence rate of local recurrence was 32%. The five-year overall survival in patients with squamous cell carcinoma and adenocarcinoma was 45% and 76%, respectively. The median preoperative radiation dose was 48?Gy. Orbital exenteration was performed in 7% of patients.

Conclusions: Preoperative chemoradiotherapy may be beneficial for patients with advanced sinonasal cancer when primary radical surgery is challenging. Survival outcomes were comparable to outcomes reported in the literature despite conservative surgery and relatively low radiation doses in patients with locally advanced tumors.     

Homeostatic expansion of autoreactive immunoglobulin-secreting cells in the Rag2 mouse model of Omenn syndrome

Hypomorphic RAG mutations, leading to limited V(D)J rearrangements, cause Omenn syndrome (OS), a peculiar severe combined immunodeficiency associated with autoimmune-like manifestations. Whether B cells play a role in OS pathogenesis is so far unexplored. Here we report the detection of plasma cells in lymphoid organs of OS patients, in which circulating B cells are undetectable. Hypomorphic Rag2^R229Q knock-in mice, which recapitulate OS, revealed, beyond severe B cell developmental arrest, a normal or even enlarged compartment of immunoglobulin-secreting cells (ISC). The size of this ISC compartment correlated with increased expression of Blimp1 and Xbp1, and these ISC were sustained by elevated levels of T cell derived homeostatic and effector cytokines. The detection of high affinity pathogenic autoantibodies toward target organs indicated defaults in B cell selection and tolerance induction. We hypothesize that impaired B cell receptor (BCR) editing and a serum B cell activating factor (BAFF) abundance might contribute toward the development of a pathogenic B cell repertoire in hypomorphic Rag2^R229Q knock-in mice. BAFF-R blockade reduced serum levels of nucleic acid-specific autoantibodies and significantly ameliorated inflammatory tissue damage. These findings highlight a role for B cells in OS pathogenesis.Omenn syndrome (OS) is an inherited disorder characterized by the paradoxical coexistence of immunodeficiency and autoimmunity. OS is a genetically heterogeneous condition caused by a variety of genetic defects impairing lymphocyte development (Villa et al., 2008). Affected patients manifest with symptoms of severe combined immunodeficiency (SCID), including an increased occurrence of life-threatening infections, failure to thrive, and, in particular, autoimmune-like clinical features including early-onset severe erythrodermia, alopecia, hepato-splenomegaly, and lymphadenopathy (Omenn, 1965; Ochs et al., 1974). The best-characterized defects leading to OS are hypomorphic mutations in RAG genes, the first players in V(D)J recombination (Villa et al., 1998, 1999). The hallmark of OS, as a consequence of residual recombinase activity, is a peculiar immune phenotype made up of normal or elevated numbers of activated yet poorly functional T cells, with a highly restricted oligoclonal TCR repertoire. Such T cells infiltrate various organs, including skin, gut, spleen, and liver, resulting in profound tissue damage (Harville et al., 1997; Rieux-Laucat et al., 1998; Signorini et al., 1999). More recently, we and others have reported hypomorphic Rag mouse mutants that mimic many features of human OS (Khiong et al., 2007; Marrella et al., 2007); the study of these mice has led to a better understanding of the complexity of OS pathogenesis. Together, these models have clearly demonstrated that, in lymphopenic conditions, abnormal compensatory peripheral T cell proliferation and reduced thymic output could favor the expansion of T cell clones with inappropriate self-reactivity, and predispose to the development of immunopathology. Moreover, the lack of thymic Aire expression and the markedly reduced number of Foxp3⁺ regulatory T cells suggested that impairment in both central and peripheral mechanisms of tolerance may contribute toward the development of autoimmunity both in mice (Marrella et al., 2007) and in humans (Poliani et al., 2009; Cassani et al., 2010).In contrast, the B cell defect still remains one puzzling aspect of OS. Most of the OS patients have high IgE and residual IgG and/or IgM serum levels, though are virtually devoid of circulating B cells. On the other hand, later studies have shown that hypomorphic RAG mutations can, indeed, be associated with milder B cell phenotypes and, in such cases, Ig may be variably present (Villa et al., 2001; Sobacchi et al., 2006). The basis for this broad clinical spectrum is largely unknown, but epigenetic and environmental factors may play a causative role. Consistent with these observations, spontaneous hypomorphic Rag1 mutant mice showed high serum levels not only of IgE but also of IgG and IgM isotypes. In the periphery, partial B cell maturation occurred, displaying a restricted BCR repertoire. Moreover, B cells in these mice responded to antigen challenge and T cell help, in agreement with the presence of functional germinal centers (GCs; Khiong et al., 2007). In contrast to the leaky B cell defect in this murine model, B cell differentiation seemed more heavily affected in Rag2^R229Q mice, similar to patients with typical OS (Noordzij et al., 2002). Indeed, a severe arrest at the pro–B stage was evident in the BM and was associated to a dearth of mature functional B lymphocytes in the peripheral lymphoid organs, which are depleted of B cell follicles (Marrella et al., 2007). Analogous to archetypal OS, the origin of elevated serum IgE levels in these mice remains to be elucidated.Several lines of evidence led us to hypothesize that defects in RAG-mediated Ig gene editing/revision, either in the BM or in peripheral lymphoid tissues, might contribute to the development of the autoimmune phenotype (Hillion et al., 2005; Wang and Diamond, 2008). In addition to genetic susceptibility, autoreactive B cells can arise from the inability of a defective immune response to eradicate environmental pathogens. This results in a compensatory, often exaggerated chronic inflammatory response, ultimately leading to tissue damage and autoimmunity (Münz et al., 2009). Such a process may be favored in OS patients, in part because of defaults in the cellular and molecular components responsible for keeping inflammation in check (Villa et al., 2008).Here, we have investigated the central and peripheral development of B cells in Rag2^R229Q mice, their function, as well as their contribution to the OS immunopathology. Our results show that in the presence of a severe BM B cell developmental defect, homeostatic and effector cytokines sustain the peripheral expansion of a few “nonconventional” mature, activated B cells, which engender a relatively increased compartment of Ig-secreting cells (ISCs). The resulting peripheral B cells are responsive to TLR agonists and T cell–independent antigens. We demonstrate that sera from Rag2^R229Q mice contain high-affinity anti-dsDNA and tissue-specific autoantibodies. Rag2^R229Q B cells display impaired receptor editing, and mutant mice have increased serum BAFF levels. Notably, BAFF-mediated rescue of autoreactive B cell clones was prevented by selective BAFF-R blockade, resulting in significant amelioration of tissue damage. Collectively, these findings point to an as yet unrecognized role of B cells in the OS immunopathology.     

Hyperfractionated-accelerated or conventionally fractionated radiotherapy for early glottic cancer.

PURPOSE: To evaluate the effect of shortening overall treatment time by hyperfractionated-accelerated radiotherapy for T2N(0)M(0) glottic carcinomas. Results for local control and survival were calculated and compared to those for T1N(0)M(0) tumors treated with a once-a-day fractionated schedule. METHODS AND MATERIALS: Between 1990 and 1998, 92 patients with T1N(0)M(0) and 45 patients with T2N(0)M(0) glottic cancers were treated with radical radiotherapy. The T1N(0)M(0) tumors were treated with a once-a-day fractionated schedule lasting 6.5 weeks to a total dose of 62.4 Gy. The T2N(0)M(0) tumors received a split-course hyperfractionated-accelerated treatment over a total of 4.5 weeks to a total dose of 64.6 Gy.Results: The 5-year local control was 85% for T1N(0)M(0) and 88% for T2N(0)M(0), whereas the 5-year locoregional control was 85% for both groups. The 5-year overall survival was 70% and 53% for T1N(0)M(0) and T2N(0)M(0), respectively. No significant statistical difference was found between the two groups for the parameters analyzed. The number of serious late complications was few and comparable for the two groups. CONCLUSIONS: Hyperfractionated-accelerated radiotherapy proved beneficial for T2N(0)M(0) glottic cancer, giving local control rates comparable to those for T1N(0)M(0) tumors.     

Barriers and Facilitators for Implementing Motivational Interviewing as a Return to Work Intervention in a Norwegian Social Insurance Setting: A Mixed Methods Process Evaluation

Journal of Occupational Rehabilitation - Purpose The aim of this study was to evaluate potential barriers and facilitators for implementing motivational interviewing (MI) as a return to work (RTW)...     

Persistent expression of autoantibodies in SLE patients in remission

A majority of the antibodies expressed by nascent B cells in healthy humans are self-reactive, but most of these antibodies are removed from the repertoire during B cell development. In contrast, untreated systemic lupus erythematosus (SLE) patients fail to remove many of the self-reactive and polyreactive antibodies from the naive repertoire. Here, we report that SLE patients in clinical remission continue to produce elevated numbers of self-reactive and polyreactive antibodies in the mature naive B cell compartment, but the number of B cells expressing these antibodies is lower than in patients with active disease. Our finding that abnormal levels of self-reactive mature naive B cells persist in the majority of patients in clinical remission suggests that early checkpoint abnormalities are an integral feature of SLE.