Immune activation alters cellular and humoral responses to yellow fever 17D vaccine.

Background. Defining the parameters that modulate vaccine responses in African populations will be imperative to design effective vaccines for protection against HIV, malaria, tuberculosis, and dengue virus infections. This study aimed to evaluate the contribution of the patient-specific immune microenvironment to the response to the licensed yellow fever vaccine 17D (YF-17D) in an African cohort. Methods. We compared responses to YF-17D in 50 volunteers in Entebbe, Uganda, and 50 volunteers in Lausanne, Switzerland. We measured the CD8+ T cell and B cell responses induced by YF-17D and correlated them with immune parameters analyzed by flow cytometry prior to vaccination. Results. We showed that YF-17D-induced CD8+ T cell and B cell responses were substantially lower in immunized individuals from Entebbe compared with immunized individuals from Lausanne. The impaired vaccine response in the Entebbe cohort associated with reduced YF-17D replication. Prior to vaccination, we observed higher frequencies of exhausted and activated NK cells, differentiated T and B cell subsets and proinflammatory monocytes, suggesting an activated immune microenvironment in the Entebbe volunteers. Interestingly, activation of CD8+ T cells and B cells as well as proinflammatory monocytes at baseline negatively correlated with YF-17D-neutralizing antibody titers after vaccination. Additionally, memory T and B cell responses in preimmunized volunteers exhibited reduced persistence in the Entebbe cohort but were boosted by a second vaccination. Conclusion. Together, these results demonstrate that an activated immune microenvironment prior to vaccination impedes efficacy of the YF-17D vaccine in an African cohort and suggest that vaccine regimens may need to be boosted in African populations to achieve efficient immunity. Trial registration. Registration is not required for observational studies. Funding. This study was funded by Canada's Global Health Research Initiative, Defense Threat Reduction Agency, National Institute of Allergy and Infectious Diseases, Bill & Melinda Gates Foundation, and United States Agency for International Development.

Humoral and cellular rejection after combined liver-kidney transplantation in low immunologic risk recipients.

Combined liver-kidney transplantation is considered a low risk for immunologic complication. We report an unusual case of identical ABO liver-kidney recipient without preformed anti-human leukocyte antigen (HLA) antibodies, transplanted across a T- and B-cell-negative cross-match and complicated by early acute humoral and cellular rejection, first in the liver then in the kidney. While analyzing the immunologic complications in our cohort of 12 low-risk combined liver-kidney recipients, only one recipient experienced a rejection episode without detection of anti-HLA antibody over time. Although humoral or cellular rejection is rare after combined kidney-liver transplantation, our data suggest that even in low-risk recipients, the liver does not always systematically protect the kidney from acute rejection. Indeed, the detection of C4d in the liver should be carefully followed after combined liver-kidney transplantation.

Double seronegative myasthenia gravis with antiphospholipid syndrome: a case report.

INTRODUCTION: Myasthenia gravis is an autoimmune disease characterized by fluctuating muscle weakness. It is often associated with other autoimmune disorders, such as thyroid disease, rheumatoid arthritis, systemic lupus erythematosus, and antiphospholipid syndrome. Many aspects of autoimmune diseases are not completely understood, particularly when they occur in association, which suggests a common pathogenetic mechanism. CASE PRESENTATION: We report a case of a 42-year-old Caucasian woman with antiphospholipid syndrome, in whom myasthenia gravis developed years later. She tested negative for both antibodies against the acetylcholine receptor and against muscle-specific receptor tyrosine-kinase, but had typical decremental responses at the repetitive nerve stimulation testing, so that a generalized myasthenia gravis was diagnosed. Her thromboplastin time and activated partial thromboplastin time were high, anticardiolipin and anti-β2 glycoprotein-I antibodies were slightly elevated, as a manifestation of the antiphospholipid syndrome. She had a good clinical response when treated with a combination of pyridostigmine, prednisone and azathioprine. CONCLUSIONS: Many patients with myasthenia gravis test positive for a large variety of auto-antibodies, testifying of an immune dysregulation, and some display mild T-cell lymphopenia associated with hypergammaglobulinemia and B-cell hyper-reactivity. Both of these mechanisms could explain the occurrence of another autoimmune condition, such as antiphospholipid syndrome, but further studies are necessary to shed light on this matter.Clinicians should be aware that patients with an autoimmune diagnosis such as antiphospholipid syndrome who develop signs and neurological symptoms suggestive of myasthenia gravis are at risk and should prompt an emergent evaluation by a specialist.

PTLD Burkitt Lymphoma in a Patient with Remote Lymphomatoid Granulomatosis.

Posttransplant lymphoproliferative disorder (PTLD) is a potentially fatal complication of solid organ transplantation. The majority of PTLD is of B-cell origin, and 90% are associated with the Epstein-Barr virus (EBV). Lymphomatoid granulomatosis (LG) is a rare, EBV-associated systemic angiodestructive lymphoproliferative disorder, which has rarely been described in patients with renal transplantation. We report the case of a patient with renal transplantation for SLE, who presented, 9 months after renal transplantation, an EBV-associated LG limited to the intracranial structures that recovered completely after adjustment of her immunosuppressive treatment. Nine years later, she developed a second PTLD disorder with central nervous system initial manifestation. Workup revealed an EBV-positive PTLD Burkitt lymphoma, widely disseminated in most organs. In summary, the reported patient presented two lymphoproliferative disorders (LG and Burkitt's lymphoma), both with initial neurological manifestation, at 9 years interval. With careful reduction of the immunosuppression after the first manifestation and with the use of chemotherapy combined with radiotherapy after the second manifestation, our patient showed complete disappearance of neurologic symptoms and she is clinically well with good kidney function. No recurrence has been observed by radiological imaging until now.

Lymphome surrénalien primaire bilatéral [Primary bilateral adrenal lymphoma]

When abdominal imaging reveals the existence of unsuspected adrenal masses, a diagnostic strategy is necessary. We report the case of a woman presenting with pulmonary embolism, in whom abdominal ultrasound revealed voluminous masses in both adrenals without clinical or biological signs of hormone hypersecretion, but with mild primary adrenal failure. From a CT scan-directed needle biopsy of the right adrenal mass and subsequent staging we were able to diagnose a primary bilateral adrenal lymphoma, diffuse large B-cell type (REAL/WHO). On CHOP chemotherapy both adrenal masses decreased dramatically and the patient is in remission 18 months later. Primary adrenal lymphoma is a rare condition, since 65 cases have been reported to date. Histological diagnosis is nevertheless important, in view of the excellent response to specific therapy observed in some cases.

The BAFF/APRIL system in SLE pathogenesis.

Systemic lupus erythematosus (SLE) is characterized by multisystem immune-mediated injury in the setting of autoimmunity to nuclear antigens. The clinical heterogeneity of SLE, the absence of universally agreed clinical trial end points, and the paucity of validated therapeutic targets have, historically, contributed to a lack of novel treatments for SLE. However, in 2011, a therapeutic monoclonal antibody that neutralizes the cytokine TNF ligand superfamily member 13B (also known as B-cell-activating factor of the TNF family [BAFF]), belimumab, became the first targeted therapy for SLE to have efficacy in a randomized clinical trial. Because of its specificity, the efficacy of belimumab provides an opportunity to increase understanding of SLE pathophysiology. Although belimumab depletes B cells, this effect is not as powerful as that of other B-cell-directed therapies that have not been proven efficacious in randomized clinical trials. In this article, therefore, we review results suggesting that neutralizing BAFF can have effects on the immune system other than depletion of B cells. We also identify aspects of the BAFF system for which data in relation to SLE are still missing, and we suggest studies to investigate the pathogenesis of SLE and ways to refine anti-BAFF therapies. The role of a related cytokine, TNF ligand superfamily member 13 (also known as a proliferation-inducing ligand [APRIL]) in SLE is much less well understood, and hence this review focuses on BAFF.

38

This chapter presents a series of case studies with multiple choice questions and answers that focus on the pitfalls in the diagnosis of non-Hodgkin's lymphomas. It commences with a discourse on the diagnosis B-cell lymphomas. A subset of aggressive and high grade B-cell lymphomas that feature characteristics intermediate between those of diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL) are grouped together under the designation BCLU-DLBCL/BL. The chapter discusses the diagnosis of nodular lymphocytic predominant Hodgkin lymphoma (NLPHL). It also focuses on the diagnosis of primary mediastinal (thymic) large B-cell lymphoma T-lymphoblastic leukemia/lymphoma, pediatric follicular lymphoma, and cyclin D1-negative mantle cell lymphoma (MCL).

MHC class II expression is differentially regulated in plasmacytoid and conventional dendritic cells.

Major histocompatibility complex (MHC) class II-restricted antigen presentation is essential for the function of dendritic cells (DCs). We show here that plasmacytoid DCs (pDCs) differ from all other DC subsets with respect to expression of CIITA, the 'master regulator' of MHC class II genes. The gene encoding CIITA is controlled by three cell type-specific promoters: pI, pIII and pIV. With gene targeting in mice, we demonstrate that pDCs rely strictly on the B cell promoter pIII, whereas macrophages and all other DCs depend on pI. The molecular mechanisms driving MHC class II expression in pDCs are thus akin to those operating in lymphoid rather than myeloid cells.

Improving the chance of cure of follicular lymphoma by combining immunotherapy and radioimmunotherapy based on anti-CD20 antibodies?

Right ventricular and left ventricular systolic time intervals (RVSTIs and LVSTIs) were measured in normal term and preterm infants from 1 hour to 90 days of life. LVSTIs in both term and preterm infants were similar in the first five days of life. The ratio of left pre-ejection period (LPEP) to left ventricular ejection time (LVET) was lower in preterm infants older than age 5 days. Estimated gestational age had no influence on LVSTI. The ratio of right pre-ejection period (RPEP) to right ventricular ejection time (RVET) was lower in preterm infants (0.32) than in term newborns (0.37). The preterm RPEP/RVET ratio decreased with age, but at a slower rate than in term babies. This was consistent with the lower pulmonary vascular resistance present in preterm infants.

aIr-1, a newly found locus on mouse chromosome 16 encoding a trans-acting activator factor for MHC class II gene expression.

RJ 2.2.5 is a human B cell line that has lost the capacity to express MHC class II genes. The human class II-positive phenotype is restored in somatic cell hybrids between RJ 2.2.5 and mouse spleen cells. By karyotype and molecular studies of an informative family of hybrids we have now shown that the reexpression of human class II gene products, as well as the maintenance of the mouse class II-positive phenotype, correlates with the presence of mouse chromosome 16. Thus, the existence on this mouse chromosome of a newly found locus, designated by us aIr-1, that determines a trans-acting activator function for class II gene expression, is established. Possible implications of this finding are discussed.

Critical role for Ets, AP-1 and GATA-like transcription factors in regulating mouse Toll-like receptor 4 (Tlr4) gene expression.

TLR4 (Toll-like receptor 4) is essential for sensing the endotoxin of Gram-negative bacteria. Mutations or deletion of the TLR4 gene in humans or mice have been associated with altered predisposition to or outcome of Gram-negative sepsis. In the present work, we studied the expression and regulation of the Tlr4 gene of mouse. In vivo, TLR4 levels were higher in macrophages compared with B, T or natural killer cells. High basal TLR4 promoter activity was observed in RAW 264.7, J774 and P388D1 macrophages transfected with a TLR4 promoter reporter vector. Analysis of truncated and mutated promoter constructs identified several positive [two Ets (E twenty-six) and one AP-1 (activator protein-1) sites] and negative (a GATA-like site and an octamer site) regulatory elements within 350 bp upstream of the transcriptional start site. The myeloid and B-cell-specific transcription factor PU.1 bound to the proximal Ets site. In contrast, none among PU.1, Ets-1, Ets-2 and Elk-1, but possibly one member of the ESE (epithelium-specific Ets) subfamily of Ets transcription factors, bound to the distal Ets site, which was indispensable for Tlr4 gene transcription. Endotoxin did not affect macrophage TLR4 promoter activity, but it decreased TLR4 steady-state mRNA levels by increasing the turnover of TLR4 transcripts. TLR4 expression was modestly altered by other pro- and anti-inflammatory stimuli, except for PMA plus ionomycin which strongly increased promoter activity and TLR4 mRNA levels. The mouse and human TLR4 genes were highly conserved. Yet, notable differences exist with respect to the elements implicated in gene regulation, which may account for species differences in terms of tissue expression and modulation by microbial and inflammatory stimuli.

Immune response to MMTV infection.

Mouse mammary tumor virus (MMTV) has developed a strategy of exploitation of the immune response. It infects dendritic cells and B cells and requires this infection to establish an efficient chronic infection. This allows transmission of infection to the mammary gland, production in milk and infection of the next generation via lactation. The elaborate strategy developed by MMTV utilizes several key elements of the normal immune response. Starting with the infection and activation of dendritic cells and B cells leading to the expression of a viral superantigen followed by professional superantigen-mediated priming of naive polyclonal T cells by dendritic cells and induction of superantigen-mediated T cell B cell collaboration results in long-lasting germinal center formation and production of long-lived B cells that can later carry the virus to the mammary gland epithelium. Later in life it can induce transformation of mammary gland epithelium by integrating close to proto-oncogenes leading to their overexpression. Genes encoding proteins of the Wnt-pathway are preferential targets. This review will put these effects in the context of a normal immune response and summarize important facts on MMTV biology.

Early Stage Primary Bone Lymphoma: A Retrospective, Multicenter Rare Cancer Network Study

PURPOSE/OBJECTIVE(S): Primary bone lymphoma (PBL) represents less than 1% of all malignant lymphomas, and 4-5% of all extranodal lymphomas. In this study, we assessed the disease profile, outcome, and prognostic factors in patients with stage I and II PBL. MATERIALS/METHODS: Between 1987 and 2008, 116 consecutive patients with PBL treated in 13 RCNinstitutions were included in this study. Inclusion criteriawere: age.17 yrs, PBLin stage I and II, andminimum6months follow-up. The median agewas 51 yrs (range: 17-93).Diagnosticwork-up included plain boneXray (74%of patients), scintigraphy (62%), CT-scan (65%),MRI (58%), PET (18%), and bone-marrow biopsy (84%).All patients had biopsy-proven confirmation of non-Hodgkin's lymphoma (NHL). The histopathological type was predominantly diffuse large B-cell lymphoma (78%) and follicular lymphoma (6%), according to theWHOclassification. One hundred patients had a high-grade, 7 intermediate and 9 low-gradeNHL. Ninety-three patients had anAnn-Arbor stage I, and 23 had a stage II. Seventy-seven patients underwent chemoradiotherapy (CXRT), 12 radiotherapy (RT) alone, 10 chemotherapy alone (CXT), 9 surgery followed by CXRT, 5 surgery followed by CXT, and 2 surgery followed by RT. One patient died before treatment.Median RT dosewas 40Gy (range: 4-60).Themedian number ofCXTcycleswas 6 (range, : 2-8).Median follow-upwas 41months (range: 6-242). RESULTS: Following treatment, the overall response rate was 91% (CR 74%, PR 17%). Local recurrence was observed in 12 (10%) patients, and systemic recurrence in 17 (15%) patients. Causes of death included disease progression in 16, unrelated disease in 6, CXT-related toxicity in 1, and secondary cancer in 2 patients. The 5-yr overall survival (OS), disease-free survival (DFS), lymphoma- specific survival (LSS), and local control (LC) were 76%, 69%, 78%, and 92%, respectively. In univariate analyses (log-rank test), favorable prognostic factors for survival were: age\50 years (p = 0.008), IPI score #1 (p = 0.009), complete response (p\0.001), CXT (p = 0.008), number of CXT cycles $6 (p = 0.007), and RT dose . 40 Gy (p = 0.005). In multivariate analysis age, RT dose, complete response, and absence of B symptoms were independent factors influencing the outcome. There were 3 patients developing grade 3 or more (CTCAE.V3.0) toxicities. CONCLUSIONS: This large multicenter study, confirms the relatively good prognosis of early stage PBL, treated with combined CXRT. Local control was excellent, and systemic failure occurred infrequently. A sufficient dose of RT (. 40 Gy) and complete CXT regime (. 6 cycles) were associated with a better outcome. Combined modality appears to be the treatment of choice.

Synergistic action of GA-binding protein and glucocorticoid receptor in transcription from the mouse mammary tumor virus promoter.

B lymphocytes are among the first cells to be infected by mouse mammary tumor virus (MMTV), and they play a crucial role in its life cycle. To study transcriptional regulation of MMTV in B cells, we have analyzed two areas of the long terminal repeat (LTR) next to the glucocorticoid receptor binding site, fp1 (at position -139 to -146 from the cap site) and fp2 (at -157 to -164). Both showed B-cell-specific protection in DNase I in vitro footprinting assays and contain binding sites for Ets transcription factors, a large family of proteins involved in cell proliferation and differentiation and oncogenic transformation. In gel retardation assays, fp1 and fp2 bound the heterodimeric Ets factor GA-binding protein (GABP) present in B-cell nuclear extracts, which was identified by various criteria: formation of dimers and tetramers, sensitivity to pro-oxidant conditions, inhibition of binding by specific antisera, and comigration of complexes with those formed by recombinant GABP. Mutations which prevented complex formation in vitro abolished glucocorticoid-stimulated transcription from an MMTV LTR linked to a reporter gene in transiently transfected B-cell lines, whereas they did not affect the basal level. Exogenously expressed GABP resulted in an increased level of hormone response of the LTR reporter plasmid and produced a synergistic effect with the coexpressed glucocorticoid receptor, indicating cooperation between the two. This is the first example of GABP cooperation with a steroid receptor, providing the opportunity for studying the integration of their intracellular signaling pathways.

Canonical WNT signaling in hematopoiesis and leukemia

SummaryCanonical Wnt signaling is crucial for embryonic development and the homeostasis of certain adult tissues such as the gut and the skin. The role of canonical Wnt signaling in hematopoiesis is still debated. The expression of a dominant-active β-catenin in hematopoietic stem cells (HSCs) enhances the self-renewal capacity of HSCs but is detrimental for long-term hematopoiesis. In contrast, loss of function experiments show that absence of β- and γ-catenin does not impair steady-state hematopoiesis. It has been argued that the inducible deletion of β-catenin using the IFN-responsive Mx promoter may somehow influence stem cell fate. Herein we used the constitutive deletion of β-catenin specifically in hematopoietic cells to show that the absence of β- catenin, as well as γ-catenin deletion, does not impair normal hematopoiesis and self-renewal capacity of HSCs.Dysregulation of canonical Wnt signaling is causal for several types of cancer, including colon carcinoma or breast cancer. Recently, it was found that Wnt signal transduction was upregulated in certain leukemias. Based on these data, we have investigated whether β- and γ-catenin play a role for the induction of leukemias by oncogenic BCR-ABL translocation product. We show that the induction of B-ALL (B cell acute lymphocytic leukemia) is strongly reduced in the absence of γ-catenin, while the induction of CML (chronic myeloid leukemia) occurs at a normal rate. In the combined absence of β- and γ-catenin the induction of both CML and B-ALL is essentially blocked. Consistent with these data others have found that β-catenin is essential for the induction of CML by BCR-ABL.Collectively, we find that β- and γ-catenin are dispensable for normal hematopoiesis but essential for the development of BCR-ABL induced leukemias. These findings suggest that the canonical Wnt pathway may represent a promising target for the therapy of leukemia.RésuméLa voie de signalisation canonique Wnt est essentielle pour le développement embryonnaire ainsi que l'homéostasie de certains tissus adultes, comme les intestins et la peau. Le rôle de la voie canonique Wnt pour l'hématopoïèse est encore incertain. D'un coté l'expression d'une forme active de β-catenine dans les cellules souches de la moelle augmente leur potentiel d'auto- renouvellement mais est préjudiciable pour l'hématopoïèse à long terme. Par contre, l'absence de β- et γ-catenine n'empêche pas le déroulement normal de l'hématopoïèse. La façon dont est supprimée β-catenine, en utilisant le promoteur IFN-inductible Mx, pourrait influencer le sort des cellules souches. Ici nous détruisons β-catenine spécifiquement dans les cellules hématopoïétiques de manière constitutive et montrons que, en combinaison avec l'absence de γ-catenine, l'absence de β-catenine n'affecte pas le déroulement normal de l'hématopoïèse et la capacité des cellules souches de la moelle à se renouveler.Plusieurs sortes de cancers, comme celui du colon ou du sein, sont parfois dus à une dérégulation de la voie canonique Wnt. Récemment, certaines leucémies ont présenté une activation du signal Wnt. A partir de ces données, nous avons examiné si β- et γ-catenine jouent un rôle dans l'induction des leucémies causées par le produit de translocation BCR-ABL. Nous avons montré que l'induction de la leucémie aiguë lymphoïde de cellules Β (LAL-B) est grandement diminuée en l'absence de γ-catenin, alors que l'induction de la leucémie myéloïde chronique (LMC) n'est pas affectée. En l'absence des deux catenines, l'induction des deux leucémies LAL-B et LMC est presque complètement bloquée. En confirmation de nos données, un autre groupe a montré que β-catenine est essentielle pour le développement de la LMC. Ensemble, ces données nous montrent que β- et γ-catenine ne sont pas nécessaires pour l'hématopoïèse normale, mais essentielle pour le développement des leucémies induites par BCR-ABL. Cela suggère que la voie de signalisation canonique Wnt est une cible prometteuse pour de futures thérapies.