Upper and lower gastrointestinal endoscopies in patients over 85 years of age: Risk-benefit evaluation of a longitudinal cohort

After age 85, upper and lower gastrointestinal (GI) endoscopy may be indicated in 5% to 10% of inpatients, but the risk-benefit ratio is unknown. We studied patients older than 85 years undergoing upper and lower GI endoscopy.We analyzed a retrospective cohort of inpatients older than 85 years between 2004 and 2012, all explored by upper and complete lower GI endoscopy. Initial indications, including iron deficiency anemia (IDA), other anemias, GI bleeding, weight loss, and GI symptoms, were noted, as were endoscopy or anesthesia complications, immediate endoscopic diagnosis, and the ability to modify the patients' therapeutics. Deaths and final diagnosis for initial endoscopic indication were analyzed after at least 12 months.We included 55 patients, 78% women, with a median age, reticulocyte count, hemoglobin, and ferritin levels of 87 (85-99), 56 (24-214) g/L, 8.6 (4.8-12.9) g/dL, and 56 (3-799) μg/L, respectively. IDA was the most frequent indication for endoscopy (60%; n = 33). Immediate diagnoses were found in 64% of the patients (n = 35), including 25% with GI cancers (n = 14) and 22% with gastroduodenal ulcers or erosions (n = 12). Cancer diagnosis was associated with lower reticulocyte count (45 vs. 60 G/L; P = .02). Among the 35 diagnoses, 94% (n = 33) led to modifications of the patients' therapeutics, with 29% of the patients deciding on palliative care (n = 10). No endoscopic complications lead to death. Follow-up of >12 months was available in 82% (n = 45) of the patients; among these patients, 40% (n = 27) died after an average 24 ± 18 months. Cancer diagnosis was significantly associated with less ulterior red cell transfusion (0% vs. 28%; P = .02) and fewer further investigations (6.7% vs. 40%; P = .02).Upper and complete lower GI endoscopy in patients older than 85 years appears to be safe, and enables a high rate of immediate diagnosis, with significant modifications of therapeutics. GI cancers represented more than one-third of the endoscopic diagnoses.

Outcome of endoscopy-negative iron deficiency anemia in patients above 65: A longitudinal multicenter cohort

After the age of 65 years, iron deficiency anemia (IDA) requires the elimination of digestive neoplasia and is explored with upper and lower gastrointestinal (GI) endoscopy. However, such explorations are negative in 14% to 37% of patients. To further evaluate this issue, we evaluated the outcomes of patients aged over 65 years with endoscopy-negative IDA.We retrospectively analyzed the outcomes of in-patients over the age of 65 years with IDA (hemoglobin <12 g/dL and ferritin <70 μg/L) who had negative complete upper and lower GI endoscopies in 7 tertiary medical hospitals. Death, the persistence of anemia, further investigations, and the final diagnosis for IDA were analyzed after at least 12 months by calling the patients' general practitioners and using hospital records.Between 2004 and 2011, 69 patients (74% women) with a median age of 78 (interquartile range (IQR) 75-82) years and hemoglobin and ferritin levels of 8.4 (IQR 6.8-9.9) g/dL and 14 (IQR 8-27) μg/L, respectively, had endoscopy-negative IDA, and 73% of these patients received daily antithrombotics. After a follow-up of 41 ± 22 months, 23 (33%) of the patients were dead; 5 deaths were linked with the IDA, and 45 (65%) patients had persistent anemia, which was significantly associated with death (P = 0.007). Further investigations were performed in 45 patients; 64% of the second-look GI endoscopies led to significant changes in treatment compared with 25% for the capsule endoscopies. Conventional diagnoses of IDA were ultimately established for 19 (27%) patients and included 3 cancer patients. Among the 50 other patients, 40 (58%) had antithrombotics.In endoscopy-negative IDA over the age of 65 years, further investigations should be reserved for patients with persistent anemia, and second-look GI endoscopy should be favored. If the results of these investigations are negative, the role of antithrombotics should be considered.

Ikaros Is a Negative Regulator of B1 Cell Development and Function

B1 B cells secrete most of the circulating natural antibodies and are considered key effector cells of the innate immune response. However, B1 cell-associated antibodies often cross-react with self-antigens, which leads to autoimmunity, and B1 cells have been implicated in cancer. How B1 cell activity is regulated remains unclear. We show that the Ikaros transcription factor is a major negative regulator of B1 cell development and function. Using conditional knock-out mouse models to delete Ikaros at different locations, we show that Ikaros-deficient mice exhibit specific and significant increases in splenic and bone marrow B1 cell numbers, and that the B1 progenitor cell pool is increased ∼10-fold in the bone marrow. Ikaros-null B1 cells resemble WT B1 cells at the molecular and cellular levels, but show a down-regulation of signaling components important for inhibiting proliferation and immunoglobulin production. Ikaros-null B1 cells hyper-react to TLR4 stimulation and secrete high amounts of IgM autoantibodies. These results indicate that Ikaros is required to limit B1 cell homeostasis in the adult.

Chronic bacterial infection activates autoreactive B cells and induces isotype switching and autoantigen-driven mutations

The links between infections and the development of B-cell-mediated autoimmune diseases are still unclear. In particular, it has been suggested that infection-induced stimulation of innate immune sensors can engage low affinity autoreactive B lymphocytes to mature and produce mutated IgG pathogenic autoantibodies. To test this hypothesis, we established a new knock-in mouse model in which autoreactive B cells could be committed to an affinity maturation process. We show that a chronic bacterial infection allows the activation of such B cells and the production of nonmutated IgM autoantibodies. Moreover, in the constitutive presence of their soluble antigen, some autoreactive clones are able to acquire a germinal center phenotype, to induce Aicda gene expression and to introduce somatic mutations in the IgG heavy chain variable region on amino acids forming direct contacts with the autoantigen. Paradoxically, only lower affinity variants are detected, which strongly suggests that higher affinity autoantibodies secreting B cells are counterselected. For the first time, we demonstrate in vivo that a noncross-reactive infectious agent can activate and induce autoreactive B cells to isotype switching and autoantigen-driven mutations, but on a nonautoimmune background, tolerance mechanisms prevent the formation of consequently dangerous autoimmunity.

Anti-pseudo-PCNA type 1 (anti-SG2NA) pattern: Track down Cancer, not SLE

OBJECTIVE

Describe the clinical significance of anti-SG2NA antibodies also called anti-pseudo-PCNA type 1 (proliferating cell nuclear antigen auto-antibodies) which are rare antinuclear antibodies (ANAs) staining distinctly S/G2 proliferative HEp-2 cells by indirect immunofluorescence. By analogy with anti-PCNA antibodies, they have been suspected to be associated with systemic lupus erythematosus (SLE), cancers or viral diseases.

METHODS

From May 2006 to February 2013, 16,827 patients were tested positive for ANAs in the Laboratory of Immunology, Strasbourg, France. We retrospectively analyzed clinical and biological data from 126 patients with anti-pseudo-PCNA type 1 antibodies.

RESULTS

There was a 0.75% prevalence of anti-pseudo-PCNA type 1 Abs among ANAs(+) patients. Median age was 56.9 years (standard deviation [SD] 13.4 years) with a sex ratio female/male of 1.9. Compared to ANAs(+) patients, many more patients have been hospitalized in the Oncology and Hematology Department (23% vs. 6.3%, P < 0.05). Indeed, anti-pseudo-PCNA type 1 Abs were detected in 33 patients suffering from solid and hematological cancers (26%). Another group of patients presented various auto-immune diseases but surprisingly none of our patients was affected with SLE when 5 out of 8 patients in anti-PCNAs(+) Abs group (P < 5.10(-6)) were. Finally, the presence of anti-pseudo-PCNA type 1 Abs was associated in 30 cases with other auto-Abs reflecting a more general breakdown of B cell tolerance against other self-antigens.

CONCLUSION

Considering our results, explorations for tumors should be at least recommended for patients with anti-pseudo-PCNA type 1 Abs. Lupus disease is not associated with these autoAbs.

Validity of the global anti-phospholipid syndrome score to predict thrombosis: a prospective multicentre cohort study

OBJECTIVE

To investigate the validity of the global APS score (GAPSS) to predict thrombosis in patients with autoimmune diseases.

METHODS

This prospective cohort study included consecutive patients with aPL or SLE. aPL, aPS-PT and GAPSS were determined. A Cox proportional hazards model assessed the validity of GAPSS and identified other potential independent predictors of thrombosis.

RESULTS

One hundred and thirty-seven patients [43.5 (s.d. 15.4) years old; 107 women] were followed up for a mean duration of 43.1 (s.d. 20.7) months. Mean GAPSS was significantly higher in patients who experienced a thrombotic event compared with those without [10.88 (s.d. 5.06) vs 8.15 (s.d. 5.31), respectively, P = 0.038]. In univariate analysis, age [hazard ratio (HR) = 1.04 (95% CI 1.01, 1.08)] and GAPSS above 16 [HR = 6.86 (95% CI 1.90, 24.77)] were each significantly associated with thrombosis during follow-up, while history of arterial thrombosis [HR = 2.61 (95% CI 0.87, 7.82)] failed to reach significance. Among aPL assays, IgG aPS/PT--a component of the GAPSS--was significantly associated with thrombosis [HR = 2.95 (95% CI 1.02, 8.51)]. In multivariate analysis, GAPSS above 16 remained the only significant predictor of thrombosis [HR = 6.17 (95% CI 1.70, 22.40)].

CONCLUSION

This first external validation study confirmed that GAPSS can predict thrombosis in patients with aPL and associated autoimmune diseases.

Overexpression of Fkbp11, a feature of lupus B cells, leads to B cell tolerance breakdown and initiates plasma cell differentiation

Systemic Lupus Erythematosus (SLE) is a severe systemic autoimmune disease, characterized by multi-organ damages, triggered by an autoantibody-mediated inflammation, and with a complex genetic influence. It is today accepted that adult SLE arises from the building up of many subtle gene variations, each one adding a new brick on the SLE susceptibility and contributing to a phenotypic trait to the disease. One of the ways to find these gene variations consists in comprehensive analysis of gene expression variation in a precise cell type, which can constitute a good complementary strategy to genome wide association studies. Using this strategy, and considering the central role of B cells in SLE, we analyzed the B cell transcriptome of quiescent SLE patients, and identified an overexpression of FKBP11, coding for a cytoplasmic putative peptidyl-prolyl cis/trans isomerase and chaperone enzyme. To understand the consequences of FKBP11 overexpression on B cell function and on autoimmunity's development, we created lentiviral transgenic mice reproducing this gene expression variation. We showed that high expression of Fkbp11 reproduces by itself two phenotypic traits of SLE in mice: breakdown of B cell tolerance against DNA and initiation of plasma cell differentiation by acting upstream of Pax5 master regulator gene.

Responsiveness of the 36-item Short Form Health Survey and the Lupus Quality of Life questionnaire in SLE

OBJECTIVES

This study aimed to estimate the responsiveness to change of a generic [the 36-item Short Form Health Survey (SF-36)] and a specific health-related quality of life questionnaire [the Lupus Quality if Life questionnaire (LupusQoL)] according to SLE patients' self-reported changes in health status.

METHODS

In a cohort of 185 SLE patients, quality of life (QoL) was measured three times at 3 month intervals by the LupusQoL and SF-36 questionnaires. Anchors for responsiveness were defined by patients' global assessment of disease impact according to changes in a visual analogue scale (VAS), a 7-point Likert scale and a 0-3 scale of five patient-reported symptoms. Mean change and s.d. in worsening and improving patients according to anchors were estimated using mixed models for repeated measures. Standardized response means (SRMs) were calculated in each group.

RESULTS

Patients [mean age 39.6 years (s.d. 10.5), mean Safety of Estrogen in Lupus Erythematosus National Assessment-SLEDAI score 2.6 (s.d. 3.5)] answered a total of 515 questionnaires. For the VAS and Likert global anchors, worsening patients showed a significant decrease in all LupusQoL domains except for burden to others, body image and fatigue and all SF-36 domains with low to moderate responsiveness. Improving patients had a significant increase in all LupusQoL domains except for intimate relationship and all SF-36 domains except for physical functioning and global health with low to moderate responsiveness. Regarding similar domains in the SF-36 and LupusQoL, SRMs were higher in LupusQoL domains in improving patients, while SF-36 domains had larger SRMs in worsening patients.

CONCLUSION

Both the SF-36 and LupusQoL were responsive to changes in QoL in SLE patients over a 3 month interval. LupusQoL seems to be more appropriate to measure improvements in QoL.

IgM rheumatoid factor amplifies the inflammatory response of macrophages induced by the rheumatoid arthritis-specific immune complexes containing anticitrullinated protein antibodies

OBJECTIVES

Anticitrullinated protein antibodies (ACPA) are specifically associated with rheumatoid arthritis (RA) and produced in inflamed synovial membranes where citrullinated fibrin, their antigenic target, is abundant. We showed that immune complexes containing IgG ACPA (ACPA-IC) induce FcγR-mediated tumour necrosis factor (TNF)-α secretion in macrophages. Since IgM rheumatoid factor (RF), an autoantibody directed to the Fc fragment of IgG, is also produced and concentrated in the rheumatoid synovial tissue, we evaluated its influence on macrophage stimulation by ACPA-IC.

METHODS

With monocyte-derived macrophages from more than 40 healthy individuals and different human IgM cryoglobulins with RF activity, using a previously developed human in vitro model, we evaluated the effect of the incorporation of IgM RF into ACPA-IC.

RESULTS

IgM RF induced an important amplification of the TNF-α secretion. This effect was not observed in monocytes and depended on an increase in the number of IgG-engaged FcγR. It extended to the secretion of interleukin (IL)-1β and IL-6, was paralleled by IL-8 secretion and was not associated with overwhelming secretion of IL-10 or IL-1Ra. Moreover, the RF-induced increased proinflammatory bioactivity of the cytokine response to ACPA-IC was confirmed by an enhanced, not entirely TNF-dependent, capacity of the secreted cytokine cocktail to prompt IL-6 secretion by RA synoviocytes.

CONCLUSIONS

By showing that it can greatly enhance the proinflammatory cytokine response induced in macrophages by the RA-specific ACPA-IC, these results highlight a previously undescribed, FcγR-dependent strong proinflammatory potential of IgM RF. They clarify the pathophysiological link between the presence of ACPA and IgM RF, and RA severity.

Circulating TFH subset distribution is strongly affected in lupus patients with an active disease

Follicular helper T cells (T_FH) represent a distinct subset of CD4⁺ T cells specialized in providing help to B lymphocytes, which may play a central role in autoimmune diseases having a major B cell component such as systemic lupus erythematosus. Recently, T_FH subsets that share common phenotypic and functional characteristics with T_FH cells from germinal centers, have been described in the peripheral blood from healthy individuals. The aim of this study was to analyze the distribution of such populations in lupus patients. Circulating T_FH cell subsets were defined by multicolor flow cytometry as T_FH17 (CXCR3^-CCR6⁺), T_FH1 (CXCR3 ⁺ CCR6^-) or T_FH2 (CXCR3^-CCR6^-) cells among CXCR5 ⁺ CD45RA^-CD4⁺ T cells in the peripheral blood of 23 SLE patients and 23 sex and age-matched healthy controls. IL-21 receptor expression by B cells was analyzed by flow cytometry and the serum levels of IL-21 and Igs were determined by ELISA tests. We found that the T_FH2 cell subset frequency is strongly and significantly increased in lupus patients with an active disease (SLEDAI score>8), while the T_FH1 cell subset percentage is greatly decreased. The T_FH2 and T_FH1 cell subset frequency alteration is associated with the presence of high Ig levels and autoantibodies in patient’s sera. Moreover, the T_FH2 cell subset enhancement correlates with an increased frequency of double negative memory B cells (CD27^-IgD^-CD19⁺ cells) expressing the IL-21R. Finally, we found that IgE levels in lupus patients’ sera correlate with disease activity and seem to be associated with high T_FH2 cell subset frequency. In conclusion, our study describes for the first time the distribution of circulating T_FH cell subsets in lupus patients. Interestingly, we found an increased frequency of T_FH2 cells, which correlates with disease activity. Our results suggest that this subset might play a key role in lupus pathogenesis.

Carabin deficiency in B cells increases BCR-TLR9 costimulation-induced autoimmunity

The mechanisms behind flares of human autoimmune diseases in general, and of systemic lupus in particular, are poorly understood. The present scenario proposes that predisposing gene defects favour clinical flares under the influence of external stimuli. Here, we show that Carabin is low in B cells of (NZB × NZW) F1 mice (murine SLE model) long before the disease onset, and is low in B cells of lupus patients during the inactive phases of the disease. Using knock-out and B-cell-conditional knock-out murine models, we identify Carabin as a new negative regulator of B-cell function, whose deficiency in B cells speeds up early B-cell responses and makes the mice more susceptible to anti-dsDNA production and renal lupus flare after stimulation with a Toll-like Receptor 9 agonist, CpG-DNA. Finally, in vitro analysis of NFκB activation and Erk phosphorylation in TLR9- and B-cell receptor (BCR)-stimulated Carabin-deficient B cells strongly suggests how the internal defect synergizes with the external stimulus and proposes Carabin as a natural inhibitor of the potentially dangerous crosstalk between BCR and TLR9 pathways in self-reactive B cells.

Evidence for heterogeneity of the obstetric antiphospholipid syndrome: thrombosis can be critical for antiphospholipid-induced pregnancy loss

BACKGROUND

Antiphospholipid antibodies are associated with thrombosis and repeated pregnancy losses during the antiphospholipid syndrome. Several experimental findings indicate that purified antiphospholipid antibodies are directly responsible for inflammation-induced pregnancy losses, or for disruption of the annexin A5 shield at the trophoblastic interface. We previously showed that passive transfer of CIC15, a monoclonal antiphospholipid antibody binding to cardiolipin and annexin A5 that was isolated from a patient with primary antiphospholipid syndrome, induces fetal resorption in pregnant mice.

OBJECTIVES

To investigate the mechanisms of CIC15-induced pregnancy loss.

METHODS/RESULTS

We show that CIC15 induces fetal loss through a new mechanism that is probably related to procoagulant activity. The time course is different from those of previously described models, and histologic analysis shows that the placentas are devoid of any sign of inflammation but display some signs of thrombotic events. Despite these differences, the CIC15 and 'inflammatory' models share some similarities: lack of FcγRI/III dependency, and the efficacy of heparin in preventing fetal losses. However, this latter observation is here mostly attributable to anticoagulation rather than complement inhibition, because fondaparinux sodium and hirudin show similar efficiency. In vitro, CIC15 enhances cardiolipin-induced thrombin generation. Finally, using a combination of surface-sensitive methods, we show that, although it binds complexes of cardiolipin-annexin A5, CIC15 is not able to disrupt the two-dimensional ordered arrays of annexin A5.

CONCLUSIONS

This human monoclonal antibody is responsible for pregnancy loss through a new mechanism involving thrombosis. This mechanism adds to the heterogeneity of the obstetric antiphospholipid syndrome.

B cell signature during inactive systemic lupus is heterogeneous: toward a biological dissection of lupus

Systemic lupus erythematosous (SLE) is an autoimmune disease with an important clinical and biological heterogeneity. B lymphocytes appear central to the development of SLE which is characterized by the production of a large variety of autoantibodies and hypergammaglobulinemia. In mice, immature B cells from spontaneous lupus prone animals are able to produce autoantibodies when transferred into immunodeficient mice, strongly suggesting the existence of intrinsic B cell defects during lupus. In order to approach these defects in humans, we compared the peripheral B cell transcriptomas of quiescent lupus patients to normal B cell transcriptomas. When the statistical analysis is performed on the entire group of patients, the differences between patients and controls appear quite weak with only 14 mRNA genes having a false discovery rate ranging between 11 and 17%, with 6 underexpressed genes (PMEPA1, TLR10, TRAF3IP2, LDOC1L, CD1C and EGR1). However, unforced hierarchical clustering of the microarrays reveals a subgroup of lupus patients distinct from both the controls and the other lupus patients. This subgroup has no detectable clinical or immunological phenotypic peculiarity compared to the other patients, but is characterized by 1/an IL-4 signature and 2/the abnormal expression of a large set of genes with an extremely low false discovery rate, mainly pointing to the biological function of the endoplasmic reticulum, and more precisely to genes implicated in the Unfolded Protein Response, suggesting that B cells entered an incomplete BLIMP1 dependent plasmacytic differentiation which was undetectable by immunophenotyping. Thus, this microarray analysis of B cells during quiescent lupus suggests that, despite a similar lupus phenotype, different biological roads can lead to human lupus.

Wegener's granuloma harbors B lymphocytes with specificities against a proinflammatory transmembrane protein and a tetraspanin

Wegener's granulomatosis (WG) is a severe autoimmune disorder ranging from localized granulomatous disease to generalised anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. A previous analysis of immunoglobulin heavy chain genes derived from tissue, i.e. Wegener's granuloma indicated selection and affinity maturation towards local antigen(s). The current study focused on determining the specificity of immunoglobulins from distinct B lymphocytes out of Wegener's granuloma. Four pairs of variable region immunoglobulin light and heavy chain genes, isolated before, were recombinantly expressed using the baculovirus/insect cell system. These immunoglobulins were then analysed for their antigenic target employing a protein macroarray based upon a human fetal brain tissue cDNA expression library. The lysosomal transmembrane protein 9B, a key regulator for TNFα activation, was identified as the putative antigenic target of two immunoglobulins and a tetraspanin, which might play a role in leukocyte activation and motility, was identified as the putative antigenic target of another one. Recombinant monoclonal antibodies out of Wegener's granuloma represent a new tool aiding in elucidation of its and WG immunopathogenesis.

[Systemic lupus erythematosus: news and therapeutic perspectives]

Lupus treatment has evolved considerably with spectacular advances that can be summarized in 10 points. Hydroxychloroquine and cyclophosphamide are still standard drugs, provided their use is optimized. Contraception and postmenopausal hormone replacement therapy have finally been tested in randomized studies with fairly reassuring results, although prudence remains essential in patients with severe lupus and above all in those with thrombotic complications (antiphospholipid syndrome). Mycophenolic acid has been shown to be useful in the treatment of lupus nephropathies, but its specific place in the therapeutic strategy remains to be defined. Other drugs (sirolimus, abatacept) are currently being evaluated. Anti-lymphocyte B therapies are growing in popularity. Rituximab and other drugs (anti-BAFF, TACI-Fc) are also being evaluated and their results appear very interesting. Interferon alpha (type I) inhibition is an attractive therapeutic approach in lupus but its use in humans is still premature. Peptide vaccination with fragments of autoantibodies or autoantigens is an elegant strategy, and preliminary results justify further studies. Anti-TNF molecules may be beneficial in lupus. Complement inhibition can be useful in lupus and antiphospholipid syndrome but drugs usable in humans (anti-C5) must be developed. Atheromatosis in lupus is the principal cause of morbidity and mortality and must be managed. Smoking cessation is essential, but other approaches (statins) should also be discussed. Many futuristic types of immune manipulation may be envisioned (proteasome inhibition, modulation of Fc gammaRIIB, and modulation of cell signaling (PI3kgamma)). Hence the perspectives are numerous. We will soon be able to optimize the treatment of our patients. Nevertheless, rigorous evaluation of the risk/benefit ratio of new drugs and of their most appropriate place in the therapeutic strategy against systemic lupus is indispensable.

Influenza virus-induced type I interferon leads to polyclonal B-cell activation but does not break down B-cell tolerance

The link between infection and autoimmunity is not yet well understood. This study was designed to evaluate if an acute viral infection known to induce type I interferon production, like influenza, can by itself be responsible for the breakdown of immune tolerance and for autoimmunity. We first tested the effects of influenza virus on B cells in vitro. We then infected different transgenic mice expressing human rheumatoid factors (RF) in the absence or in the constitutive presence of the autoantigen (human immunoglobulin G [IgG]) and young lupus-prone mice [(NZB x NZW)F(1)] with influenza virus and looked for B-cell activation. In vitro, the virus induces B-cell activation through type I interferon production by non-B cells but does not directly stimulate purified B cells. In vivo, both RF and non-RF B cells were activated in an autoantigen-independent manner. This activation was abortive since IgM and IgM-RF production levels were not increased in infected mice compared to uninfected controls, whether or not anti-influenza virus human IgG was detected and even after viral rechallenge. As in RF transgenic mice, acute viral infection of (NZB x NZW)F(1) mice induced only an abortive activation of B cells and no increase in autoantibody production compared to uninfected animals. Taken together, these experiments show that virus-induced acute type I interferon production is not able by itself to break down B-cell tolerance in both normal and autoimmune genetic backgrounds.

Auto-reactive B cells in transgenic mice

In order to understand how the natural occurrence of autoreactive B cells is controlled in normal individuals, and how self reactive B cells can escape this control during diverse clinical situations, many different transgenic mice have been generated expressing self reactive antibodies. In this review, we focus our attention on disease-associated self reactive transgenic models which show the variety of the tolerization mechanisms. The same transgenic lines are also used to analyse the effects of the autoimmune genetic background on the self reactive B cell fate, as well as to study the influence of infectious agents on the behaviour of the auto-reactive transgenic B cells.

Physiopathologie du syndrome des antiphospholipides

The antiphospholipid syndrome is characterized by the association of clinical events (thrombosis and/or obstetrical complications) and heterogeneous autoantibodies reacting with complexes of proteins and anionic phospholipids. Most of these recognized proteins can bind to anionic phospholipids and play a role in natural regulation of coagulation. Inhibition by these autoantibodies of the natural regulators of excessive coagulation is probably responsible for the prothrombotic state that characterizes this disease. Animal models have helped explain the mechanisms of obstetrical complications. Human antiphospholipid antibodies passively transferred to pregnant mice directly cause fetal resorption. This effect is mediated by complement fractions and neutrophil activation and is inhibited by heparin. The origin of these autoantibodies is still debated. Physiologically, the cause may be associated with exposure to anionic phospholipids on the surface of apoptotic cells. The affinity maturation process, which leads to the acquisition of somatic mutations, can then generate highly pathogenic antiphospholipid antibodies.

Retinoid X receptor ablation in adult mouse keratinocytes generates an atopic dermatitis triggered by thymic stromal lymphopoietin

To investigate the role of retinoid X receptors (RXRs) in epidermal homeostasis, we generated RXRalphabeta(ep-/-) somatic mutants in which both RXRalpha and RXRbeta are selectively ablated in epidermal keratinocytes of adult mice. These mice develop a chronic dermatitis mimicking that observed in atopic dermatitis (AD) patients. In addition, they exhibit immunological abnormalities including elevated serum levels of IgE and IgG, associated with blood and tissue eosinophilia, indicating that keratinocyte-selective ablation of RXRs also generates a systemic syndrome similar to that found in AD patients. Furthermore, the profile of increased expression of cytokines and chemokines in skin of keratinocyte-selective RXRalphabeta-ablated mutants was typical of a T helper 2-type inflammation, known to be crucially involved in human AD pathogenesis. Finally, we demonstrate that thymic stromal lymphopoietin, whose expression is rapidly and strongly induced in RXRalphabeta-ablated keratinocytes, plays a key role in initiating the skin and systemic AD-like pathologies.

Autoantigen, innate immunity, and T cells cooperate to break B cell tolerance during bacterial infection

Autoantibody production during infections is considered to result from nonspecific activation of low-affinity autoreactive B cells. Whether this can lead to autoimmune disease remains uncertain. We show that chronic infection by Borrelia burgdorferi of Tg animals expressing human rheumatoid factor (RF) B cells (of low or intermediate affinities) in the absence or in the constitutive presence of the autoantigen (represented here by chimeric IgG with human constant region) breaks their state of immunological ignorance, leading to the production of RFs. Surprisingly, this production was more pronounced in intermediate-affinity RF Tg mice co-expressing the autoantigen. This overproduction was mediated by immune complexes and involved synergistic signaling between the B cell receptor and Toll-like receptors and T cell help. These findings indicate that chronic infection can activate autoreactive B cells with significant affinity and creates conditions that can drive them to differentiate into memory cells. Such cells may have some physiological yet undetermined role, but in autoimmune-prone individuals, this scenario may initiate autoimmunity.

T-cell receptor Vβ gene usage in CSF lymphocytes in X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (ALD) is a peroxisomal disorder with impaired very-long-chain fatty acid (VLCFA) metabolism that produces a neurological disease with significant variability of clinical phenotypes even within kindred. The two most common forms are the cerebral form (CALD) with an important inflammatory reaction at the active edge of demyelinating lesions, resembling some aspects of multiple sclerosis pathology, and adrenomyeloneuropathy (AMN), which involves the spinal cord and in which the inflammatory reaction is mild or absent. One hypothesis is that the phenotypic variability is related to T cell-mediated immune mechanisms playing a primary role in the demyelinating pathogenic process of CALD. The present study aims to test the hypothesis that CSF of patients with the CALD form contains highly restricted T cell populations. The variable regions of the T cell receptor beta chains (TCR Vbeta) were studied in CSF from 29 ALD patients with different phenotypes. RNA was extracted and cDNA synthesized from CSF lymphocytes; TCR Vbeta gene segments were amplified from the cDNA by polymerase chain reaction (PCR) using 20 family-specific primers. PCR products were analyzed by Southern blot. Some amplified Vbeta products were sequenced. The majority of ALD patients (21/29), whatever their phenotype, exhibited oligoclonal T cell expansion. However the overexpression of some TCR Vbeta families was heterogeneous among the different patients without any preponderance of specific Vbeta families or any clustering according to clinical phenotype. In particular a dominant TCR Vbeta utilization was not found in patients with CALD.

Pathogenic antiphospholipid antibody: an antigen-selected needle in a haystack

Antiphospholipid antibodies represent a heterogeneous group of autoantibodies directed against anionic phospholipids (PLs) usually linked to protein cofactors. Their presence during the antiphospholipid syndrome is associated with risks of thrombosis and fetal losses. Among 5 randomly selected monoclonal antiphospholipid antibodies, all originating from a single patient suffering from this autoimmune disease, only 1 induced fetal losses when passively injected into pregnant mice. Its antiphospholipid activity was dependent on annexin A5, and its variable regions contained mainly 3 replacement mutations. To clarify the role of these mutations in the pathogenicity of the antibody, they were in vitro reverted to the germ line configuration. The resulting “germ line” antibody reacted with multiple self-antigens and only partially lost its reactivity against PLs, but it was no more dependent on annexin A5 and, more importantly, was no more pathogenic. This study illustrates that the in vivo antigen-driven maturation process of natural autoreactive B cells can be responsible for pathogenicity. (Blood. 2004;104:1711-1715)

Memory B cells producing somatically mutated antiphospholipid antibodies are present in healthy individuals

Antiphospholipid antibodies (aPLs) are associated with thrombosis and recurrent abortions during autoimmune pathologies, but they are also produced in healthy individuals and during infectious diseases. To analyze the possible links between physiologic and pathologic aPLs, it is of importance to characterize normal aPL production. We took advantage of the known tropism of Epstein-Barr virus (EBV) for B cells in general, and memory B cells in particular, during primary infectious mononucleosis (IMN) in 3 patients to get access to anticardiolipin (aCL)-producing B cells. Flow cytometry analysis of these cells showed that, depending on the patient, 10% to 60% of immunoglobulin M (IgM) aCL-producing B cells express the CD27 marker of memory B cells. Single cell sorting of aCL B cells, followed by single cell reverse transcription-polymerase chain reaction (RT-PCR) amplification of their immunoglobulin variable region genes, showed that some of these cells produce mutated forms of aCL antibodies, confirming their memory B-cell origin. Considering that, during primary IMN, EBV infects and expands already pre-existing memory B cells, we conclude that healthy individuals have a discrete pool of aCL memory cells able to produce mutated forms of antibodies. The implications of this new information are discussed in light of different hypotheses regarding the origin of aCL.

Low prevalence of antibodies to glucose-6-phosphate isomerase in patients with rheumatoid arthritis and a spectrum of other chronic autoimmune disorders

OBJECTIVE

Arthritis in the K/BxN mouse model results from pathogenic immunoglobulins that recognize glucose-6-phosphate isomerase (GPI), a glycolytic enzyme residing in the cytoplasm of all cells. Antibodies directed against GPI can, alone, transfer arthritis to healthy recipients. Previous experiments have revealed significant titers of anti-GPI antibodies in the serum of many patients with rheumatoid arthritis (RA). We evaluated the generality of these observations in cohorts of patients with 12 different arthritic and chronic autoimmune diseases and in population-matched healthy control subjects.

METHODS

Anti-GPI antibodies were assayed in 811 individual serum samples by enzyme-linked immunosorbent assay with 2 forms of GPI, recombinant and native. Results were confirmed by immunoblotting.

RESULTS

Several patients had significantly elevated anti-GPI antibody titers, but without the prevalence or the specificity reported previously. Only 15% of RA patients had anti-GPI antibodies (range 12-29% in different cohorts), with a higher prevalence in patients with active disease. Psoriatic arthritis, undifferentiated arthritis, and spondylarthropathy patients also displayed anti-GPI antibodies at similar frequencies (12-25%). Similar titers were detected in a proportion (5-10%) of control subjects or patients with Crohn's disease or sarcoidosis. Very high titers were found in rare cases of RA and systemic lupus erythematosus.

CONCLUSION

No disease-specific pattern of antibody positivity to GPI was apparent. While the antibody-mediated mechanism at play in the mouse model may exemplify a generic mechanism for some forms of arthritis in humans, GPI itself does not appear to be a target common to the majority of RA patients.

Expansion of marginal zone B cells is not sufficient for the development of renal disease in NZBxNZW F1 mice

The mechanisms which govern the production of autoantibodies and of tissue damage during systemic lupus (SLE) are still unclear. In the NZBxNZW F1 (BW) model of SLE glomerulonephritis, the activation and commitment of B cells are thought to play a major role in disease progression. Previous analysis has suggested that these mice have a substantial increase of marginal zone (MZ) B cells before the occurrence of the disease. Owing to the probable role of this B cell subset in autoantibody production, it was important to define the possible link between this abnormality and the occurrence of kidney damage. Using cytofluorometry analysis, we followed the splenic MZ B cell phenotype in different series of mice with shared autoimmune genetic background and histologically defined renal status. By comparing BW females and BW males, NZB and NZW mice, we confirm that BW mice have an increase in MZ B cells but this MZ B cells expansion is not directly linked to tissue lesions. Genetically modified BW female mice with a restricted repertoire of B and T cell antigen receptors, and which do not develop nephritis, exhibit the same increase of MZ B cells, suggesting that this increase does not depend on a specific set of antigens. Moreover, our analysis brings to light a pre-disease state in BW males, with autoantibody production and mesangial deposits.

B cell positive selection by soluble self-antigen

It is well established that autoreactive B cells undergo negative selection. This stands in paradox with the high frequency of so-called natural autoreactive B cells producing low affinity polyreactive autoantibodies with recurrent specificities, suggesting that these B cells are selected on the basis of their autoreactivity. We previously described two transgenic mouse lines (with and without IgD) producing a human natural autoantibody (nAAb) that binds ssDNA and human Fcgamma. In the absence of human IgG, nAAb-transgenic B cells develop normally. By crossing these mice with animals expressing knockin chimeric IgG with the human Fcgamma, we now show that the constitutive expression of chimeric IgG promotes the increase of nAAb-expressing B cells. This positive selection is critically dependent on the presence of IgD, occurs in the spleen, and concerns all mature B cell subsets, with a relative preferential enrichment of marginal zone B cells. These data support the view that soluble self-Ags can result in positive clonal selection.

[The immune system: new therapeutic targets]

Control of the immune reaction can become a major goal, particularly in patients with autoimmune diseases or who express alloreactivity after organ transplantation. The most important side effect of this control is an immunodeficiency, a consequence of the wide spectrum of activity of the treatment. Thus, in order to limit the infectious risks, it would appear reasonable to try to develop new more selective strategies. A better definition of the cellular and molecular mechanisms implicated in the initiation and effector phases of autoimmune diseases authorizes the development of new therapeutic approaches able to target precise points of the immune system. There are a large number of potential targets, mainly directed at orientating the cytokinic response toward an antiinflammatory profile, neutralizating proinflammatory cytokines or their receptors, inducing regulatory lymphocytes in order to normalize the state of T and B cell tolerance, and modulating cellular cooperation and lymphocytic homing by blocking adhesion molecules. Some of these new approaches have already been validated in autoimmune diseases, others will follow soon.

A role for membrane IgD in the tolerance of pathological human rheumatoid factor B cells

Under non-autoimmune conditions, rheumatoid factor (RF) B cells coexist peacefully with their antigen (IgG), or can be transiently activated during secondary immune responses because they can present xenoantigens to specific T cells captured in immune complex form. Such a situation should lead to affinity maturation of RF B cells and potentially dangerous production of high-affinity RF. We used two lines of transgenic mice expressing a somatically mutated pathological human RF in presence (IgM and IgD) or in absence (IgM only) of surface IgD, and confirm that RF B cell tolerance can result from an antigen-induced specific, but incomplete, deletion of naive RF B cells after antigen encounter. This deletion mainly concerns immature, transitional B cells. On the contrary, mature, IgM- and IgD-expressing RF B cells are resistant to such a deletion. These IgM and IgD RF B cells are functional and activable through both B cell receptor dependent (anti-IgM) and independent (LPS) pathways, but they are not fully responsive to human IgG either in vivo or in vitro. Taken together, these results suggest that another mechanism could be involved in the silencing of mature naive IgM and IgD RF B cells.

[Pulmonary histiocytosis, then bronchiolo-alveolar cancer in HIV-1 infection]

INTRODUCTION

Langerhans cell pulmonary histiocytosis is a rare disease, primarily enhanced by smoking, and of unclear mechanism.

OBSERVATION

A 42 year-old man, smoking 25 packs-years, was infected by a type 1 human immunodeficiency virus (HIV-1). He successively developed pulmonary emphysema, Langerhans cell pulmonary histiocytosis and alveolar bronchial carcinoma of the lower right pulmonary lobe, which was fatal.

DISCUSSION

We discuss the concomitance of pulmonary histiocytosis and alveolar bronchial carcinoma, exceptional in the literature, and the eventual enhancing role of HIV-1 infection. The principal incriminating factor in pulmonary histiocytosis probably remains smoking, but the HIV-1 infection may have participated in the emergence of the neoplastic pathology.

Recombinant vaccinia viruses expressing immunoglobulin variable regions efficiently and selectively protect mice against tumoral B-cell growth

The variable regions of the immunoglobulin (Ig) expressed on the surface of a malignant B cell can be considered tumor-specific antigens and, as such, could be targets for immunotherapeutic approaches. However, because until now the immunization procedures have been complex and have given only partial protection, it was necessary to find new methods of immunotherapy. Here, we present a successful method of vaccination against B-cell tumors in a murine model. We produced recombinant vaccinia viruses (rVV) expressing the heavy and the light chain of surface Ig of a patient's malignant B cells and we tested the ability of these rVV to protect immunized mice against tumor growth of transfectomas producing the same human Ig. The protection of the mice was complete and specific to the variable region of the immunizing heavy chain although specific lymphoproliferative and cytotoxic responses were not detectable in vitro. The protection was strictly dependent on the presence of CD4 T cells and asialo GM1+ cells. Furthermore, tumor protection clearly required gamma-interferon and was partially inhibited by blocking the Fas-Fas ligand interaction. We also show, in a murine syngeneic model, that rVV expressing a poorly mutated Ig protects against the growth of Ig-producing tumor.

The clonal analysis of anticardiolipin antibodies in a single patient with primary antiphospholipid syndrome reveals an extreme antibody heterogeneity

The mechanism underlying the prothrombotic state that characterizes the primary antiphospholipid syndrome proves to be difficult to define mainly because of the variety of the phospholipid and protein targets of antiphospholipid antibodies that have been described. Much of the debate is related to the use of polyclonal antibodies during the different antiphospholipid assays. To better describe the antiphospholipid antibodies, a strategy was designed to analyze the reactivity of each one antibody making up the polyclonal anticardiolipin activity, breaking down this reactivity at the clonal level. This was performed in a single patient with primary antiphospholipid syndrome by combining (1) the antigen-specific selection of single cells sorted by flow cytometry using structurally bilayered labeled anionic phospholipids and (2) the cloning of immunoglobulin (Ig) variable (V) region genes originating from individual IgG anticardiolipin-specific B cells by a single-cell polymerase chain reaction technique. The corresponding V regions were cloned in order to express human recombinant antibodies in insect cells by a baculovirus expression system. The molecular analysis, the fine specificity, and the protein cofactor dependency of the first 5 monoclonal IgG anticardiolipins are reported here. This clonal analysis reveals the extreme heterogeneity of these antibodies, which could account for the difficulties in the previous attempts to define the pathogenic antiphospholipid response. This approach should help to unravel the complex antiphospholipid immune response and the mechanism of the prothrombotic state associated with these antibodies, but it could also shed some light on their possible origins. (Blood. 2001;97:3820-3828)

Natural autoreactive B cells in transgenic mice reproduce an apparent paradox to the clonal tolerance theory

Naturally occurring autoreactive B cells are thought to be physically eliminated or rendered functionally silent through different mechanisms of tolerance. However, multireactive low affinity natural autoantibody-producing B cells seem to escape these mechanisms in normal adults and could constitute the B cell pool from which pathological autoantibodies can emerge. To analyze this apparent paradox to the clonal tolerance theory, we have made two transgenic mouse lines (mu(k), mudelta(k)) producing a natural low affinity multireactive human autoantibody. These models enable us to test both the central tolerance mechanisms (reactivity with single-stranded DNA) and the peripheral tolerance mechanisms after Ag administration. Not only are the multireactive B cells not deleted in the bone marrow, they circulate and remain in the periphery even after the prolonged administration of Ag, the presence of membrane IgD increasing the number of mature autoreactive B cells. Self-reactive B cells are shown to be autoantigen ignorant both in vivo and in vitro, but they are not anergic because they can be easily activated through both B cell receptor-dependent and -independent pathways. Thus, these mouse lines reproduce an apparent paradox to the clonal tolerance theory meriting further investigation of the biological significance of this phenomenon.

Antiphospholipid antibodies and preeclampsia: a case-control study

OBJECTIVE

To assess the association between the occurrence first of preeclampsia and antiphospholipid antibodies.

METHODS

We conducted a prospective case-control study of 180 pregnant women with their first incidents of preeclampsia and no histories of thrombosis or systemic autoimmune diseases. Preeclampsia (n = 180) was defined as blood pressure (BP) at least 140/90 mmHg after 20 weeks' gestation and proteinuria at least 0.3 g per 24 hours. Two control subjects were matched to each case (n = 360). They were pregnant women without hypertension or proteinuria and without histories of thrombosis or systemic autoimmune disease. Lupus anticoagulant (activated partial thromboplastin time, diluted thromboplastin time, platelet neutralization procedure) and anticardiolipin antibodies (immunoenzymatic assays) were assessed in both groups, and the coagulation state (levels of thrombin-antithrombin III complexes, fragments 1 + 2 of prothrombin) was also evaluated. The analysis design was a sequential plan with 5% type I error and 95% power.

RESULTS

There was no association between antiphospholipid antibodies and preeclampsia. The odds ratio for the association was 0.95 (95% confidence interval 0.45, 2.61). Antiphospholipid antibodies were detected in eight of 180 preeclamptic women and in 19 of 360 controls. In contrast, there was a clear, confirmed activation of coagulation during preeclampsia.

CONCLUSION

Despite evidence of a prothrombotic state during preeclampsia, it is unlikely that antiphospholipid antibodies (lupus anticoagulant and anticardiolipin antibodies) represent risk factors for preeclampsia among women with no previous preeclampsia and no histories of thrombosis or systemic autoimmune disease.

[Drug-addicted prisoners: seroprevalence of human immunodeficiency virus and hepatitis B and C virus soon after the marketing of buprenorphine]

PURPOSE

Considering the importance to public health and the frequency with which drug addicts are imprisoned, we studied the prevalence of human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV), as well as drug addiction of patients admitted to the Elsau prison in Strasbourg (France).

METHODS

The prospective study included all entering inmates from 1 September to 31 October 1997 (270 persons) to whom HIV, HBV and HCV blood tests were offered as well as a questionnaire on their drug addiction.

RESULTS

Thirty-six percent of the entering inmates were drug addicts, of whom 1% were HIV positive, 11.2% HBV positive and 30% HCV positive, compared to, respectively, 0.6, 9.9 and 6.4% for non-drug addicts. Ninety-five of the 98 patients used several drugs, including buprenorphine for 53 patients. At the beginning of this study, buprenorphine had been available in France for 9 months.

CONCLUSION

The results are to be taken seriously regarding the misuse of this product in this selected population (intravenous use, multiple drug use, dealing).

Salivary gland lymphomas in patients with Sjögren's syndrome may frequently develop from rheumatoid factor B cells

OBJECTIVE

Patients with Sjögren's syndrome (SS) have an increased risk of developing monoclonal B cell non-Hodgkin's lymphomas (MNHL), which frequently occur in the salivary glands (SG). The transition from the benign lymphocyte infiltrate of the gland that characterizes SS to MNHL is not well understood. Previous sequence analyses of the expressed variable (V) region genes have supported the theory that the surface Ig (sIg) plays an important role in the initial expansion of nonmalignant B cell clones and in lymphomagenesis. However, the antigenic specificities of these B cells were unknown. We describe the specificities of the Ig expressed by 2 cases of MNHL that developed in the SG of 2 patients with SS.

METHODS

The expressed V genes were amplified by polymerase chain reaction from biopsy specimens, sequenced, and subcloned into eukaryotic expression vectors. The constructs were transfected into P3X63-Ag8.653 cells to obtain 2 monoclonal cell lines, each secreting 1 of the sIg expressed by the MNHL. These IgM were tested by enzyme-linked immunosorbent assay and immunofluorescence against a panel of antigens potentially implicated in SS.

RESULTS

Our main finding was that the Ig products of the neoplastic B cells were rheumatoid factors (RF). Contrary to expectations, they did not react with nuclear or cytoplasmic antigens, double-stranded DNA, self antigens commonly bound by natural autoantibodies, or SG tissue.

CONCLUSION

Previous analyses of V gene use have provided indirect evidence that SG MNHL may frequently express RF. We demonstrate that this hypothesis is true in the 2 patients we studied. Large-scale studies will be needed to establish the exact frequency of RF specificity among SS-associated MNHL.

From systemic T cell self-reactivity to organ-specific autoimmune disease via immunoglobulins

Rheumatoid arthritis is a common and debilitating autoimmune disease whose cause and mechanism remain a mystery. We recently described a T cell receptor transgenic mouse model that spontaneously develops a disease with most of the clinical, histological, and immunological features of rheumatoid arthritis in humans. Disease development in K/BxN mice is initiated by systemic T cell self-reactivity; it requires T cells, as expected, but B cells are also needed, more surprisingly. Here, we have identified the role of B cells as the secretion of arthritogenic immunoglobulins. We suggest that a similar scenario may unfold in some other arthritis models and in human patients, beginning with pervasive T cell autoreactivity and ending in immunoglobulin-provoked joint destruction.

AIDS Primary Central Nervous System Lymphoma: Molecular Analysis of the Expressed VH Genes and Possible Implications for Lymphomagenesis

AIDS-associated primary central nervous system lymphomas are late events that have an extremely poor prognosis. Despite different hypotheses, the brain localization of these B cell lymphomas remains an enigma. To better define the cell origin of the lymphomas and the possible role of the B cell receptor (BCR) in the brain localization and/or in the oncogenic transformation, we analyzed the V region genes of the Ig heavy chain expressed by lymphoma cells in five randomly selected patients. After amplifying the rearranged VHDJH DNA by PCR, cloning, and sequencing of the amplified products, we observed that: 1) of the five lymphomas analyzed, four were clearly monoclonal; 2) there was no preferential use of one peculiar VH family or one peculiar segment of gene; 3) the mutation analysis showed that an Ag-driven process occurred in at least two cases, probably before the oncogenic event; and 4) there was no intraclonal variability, suggesting that the hypermutation mechanism is no longer efficient in these lymphoma B cells. Taken together, our results suggest that distinct Ags could be recognized by the BCR of the lymphoma cells in different patients and that, if the Ags are responsible for the brain localization of these B cells bearing mutated BCR, other factors must be involved in B cell transformations in primary central nervous system lymphoma.