T-cells that express the gammadelta T-cell receptor, which recognize microbial or stress-induced antigens, represent a minority of blood T-cells but constitute a major proportion of intraepithelial lymphocytes in the gastrointestinal mucosa. As microbial products have been shown to translocate from the gastrointestinal tract into circulation in chronically HIV/SIV-infected individuals, we conducted a study of Vdelta1 and Vdelta2 T-cell frequency, phenotype and function in blood, spleen, lymph nodes, gastrointestinal mucosa and bronchoalveolar lavage of uninfected and chronically SIVsmE543-infected rhesus macaques (RM). We found: (i) SIV-associated inversion of Vdelta1/Vdelta2 T-cells occurs in blood and in several tissues; (ii) gammadelta T-cells are not infected by SIV in vivo; (iii) the Vdelta1/Vdelta2 inversion involves expansion of Vdelta1 T-cells; (iv) expanded Vdelta1 T-cells are phenotypically and functionally different compared to Vdelta1 T-cells from uninfected RM; and, (v) the stimulus underlying expansion of Vdelta1 T-cells appears to be microbial translocation. These data highlight the importance of microbial translocation-induced immune activation in chronically-infected individuals and provide new insights into an immune dysregulation phenomenon that is a hallmark of HIV/SIV infection. These findings may lead to novel therapeutic interventions that improve the immune responses against microbial antigens and thus decrease microbial translocation-induced immune activation.

Hemokinin-1 (HK-1), encoded by the TAC4 gene, is a tachykinin peptide that is predominantly expressed in non-neuronal cells such as immune cells. We have disrupted the mouse TAC4 gene to obtain a better understanding of the actions of HK-1 during hematopoiesis. We demonstrate here that TAC4(-/-) mice exhibit an increase of CD19(+)CD117(+)HSA(+)BP.1(-) "fraction B" pro-B cells in the bone marrow, whereas pre-B, immature and mature B cells are within normal range. We show that in vitro cultures derived from TAC4(-/-) bone marrow, sorted "fraction B" pro-B cells or purified long-term reconstituting stem cells contain significantly higher numbers of pro-B cells compared to controls, suggesting an inhibitory role for HK-1 on developing B cells. Supporting this idea we show that addition of HK-1 to cultures established from long-term reconstituting stem cells and the newly described intermediate-term reconstituting stem cells leads to a significant decrease of de novo generated pro-B cells. Based on our studies we postulate that HK-1 plays an inhibitory role in hematopoiesis and we hypothesize that it may be part of the bone marrow microenvironment which supports and regulates the proliferation and differentiation of hematopoietic cells.

Accumulation of leukemic cells in patients with chronic lymphocytic leukemia (CLL) is due to prolonged cell survival, rather than increased proliferation. Survival of CLL cells depends on microenvironmental factors. Even though long-lived in vivo, CLL cells rapidly die by spontaneous apoptosis in vitro, unless cocultured with stromal cells or their conditioned medium. In the present study, we show that survival of CLL cells is maintained in high cell density cultures, where the main pro-survival activity is delivered by monocytes. Cytokine array and ELISA studies revealed increased expression of soluble CD14 by monocytes in the presence of CLL cells. The addition of recombinant soluble CD14 to primary CLL cells resulted in significantly increased cell survival rates, which were associated with higher activity of the transcription factor NFkappaB. Quantification of serum levels of soluble CD14 revealed abnormally high levels of this protein in CLL patients, indicating a potential role of soluble CD14 in vivo. In summary, the presented data show that monocytes help in the survival of CLL cells by secreting soluble CD14, which induces NFkappaB activation in these cells, and that CLL cells actively shape their microenvironment by inducing CD14 secretion in accessory monocytes.

XLP1 (X-linked Lymphoproliferative Disease), described in the mid 1970s and molecularly defined in 1998, and XLP2, reported in 2006, are prematurely lethal genetic immunodeficiencies which share susceptibility to overwhelming inflammatory responses to certain infectious triggers. SAP (SLAM-associated protein, encoded by SH2D1A) is mutated in XLP1, and XIAP (X-linked inhibitor of apoptosis, encoded by BIRC4) is mutated in XLP2. XLP1 is a disease with multiple and variable clinical consequences including fatal hemophagocytic lymphohistiocytosis (HLH) triggered predominantly by Epstein Barr virus (EBV), the development of lymphomas, antibody deficiency, and other, rarer, consequences of immune dysregulation. To date, XLP2 has been found to cause HLH with and without exposure to EBV, and HLH is commonly recurrent in these patients. For both forms of XLP, the only curative therapy at present is allogeneic hematopoietic cell transplantation (HCT). Beyond their common genetic locus on the X-chromosome and their requirement for normal immune responses to certain viral infections, SAP and XIAP demonstrate no obvious structural nor functional similarity, are not coordinately regulated with respect to their expression, and do not appear to directly interact. In this review we describe the genetic, clinical, and immunopathologic features of these two disorders, and review current diagnostic and therapeutic strategies.

The transcription factor network in Hodgkin lymphoma (HL) represents a unique composition of proteins found in no other hematopoietic cell. Among these factors, an aberrant expression of the T cell transcription factor GATA-3 is observed in the B cell-derived Hodgkin and Reed/Sternberg (HRS) tumor cells. Herein, we elucidated the regulation and function of this factor in HL. We demonstrate binding of NFkappaB and Notch-1, two factors with deregulated activity in HL, to GATA-3 promoter elements. Interference with NFkappaB and Notch-1 activity led to decreased GATA-3 expression, indicating a dependency of deregulated GATA-3 expression on these transcription factors. Downregulation of GATA-3 in HL cell lines demonstrated its role in the regulation of IL-5, IL-13, STAT-4 and further genes. A correlation between GATA-3 and IL-13 expression was confirmed for HRS cells in HL tissues. Thus, GATA-3 shapes the cytokine expression and signalling that is typical for HL. Conclusively, aberrant GATA-3 expression in HRS cells is stimulated by the deregulated constitutive activity of NFkappaB and Notch-1, indicating a complex network of deregulated transcription factors in these cells. GATA-3 activity significantly contributes to the typical cytokine secretion of and signalling in HRS cells, which presumably plays an essential role in HL pathogenesis.

Immune Reconstitution Inflammatory Syndrome (IRIS) is a considerable problem in the treatment of HIV-infected patients. To identify immunologic correlates of IRIS, we characterized T cell phenotypic markers and serum cytokine levels in HIV patients with a range of different AIDS defining illnesses, before and at regular time-points after initiation of antiretroviral therapy (ART). Patients developing IRIS episodes displayed higher frequencies of effector memory, PD-1(+), HLA-DR(+) and Ki67(+) CD4(+) T cells than patients without IRIS. Moreover, PD-1(+) CD4(+) T cells in IRIS patients expressed increased levels of LAG-3, CTLA-4 and ICOS and had a Th1/Th17 skewed cytokine profile upon polyclonal stimulation. Elevated PD-1 and Ki67 expression was also seen in regulatory T cells of IRIS patients. Furthermore, IRIS patients displayed higher serum IFN-gamma compared to non-IRIS patients near the time of their IRIS events and higher serum IL-7 levels, suggesting that the T cell populations are also exposed to augmented homeostatic signals. In conclusion, our findings indicate that IRIS appears to be a predominantly CD4-mediated phenomenon with reconstituting effector and regulatory T cells showing evidence of increased activation from antigenic exposure. These studies are registered at http://clinicaltrials.gov as NCT00557570 and NCT00286767.

Expression of protein kinase CK2 is frequently deregulated in cancer and mounting evidence implicates CK2 in tumorigenesis. Here, we show that CK2 is overexpressed and hyperactivated in chronic lymphocytic leukemia (CLL). Inhibition of CK2 induces apoptosis of CLL cells without significantly affecting normal B and T lymphocytes. Importantly, this effect is not reversed by co-culture with OP9 stromal cells, which are otherwise capable of rescuing CLL cells from in vitro spontaneous apoptosis. CLL cell death upon CK2 inhibition is mediated by inactivation of PKC, a PI3K downstream target, and correlates with decreased PTEN activity, indicating that CK2 promotes CLL cell survival at least in part via PI3K-dependent signaling. Although CK2 antagonists induce significant apoptosis of CLL cells in all patient samples analyzed, sensitivity to CK2 blockade positively correlates with the percentage of CLL cells in the peripheral blood, beta2 microglobulin serum levels and clinical stage. These data suggest that subsets of patients with aggressive and advanced stage disease may especially benefit from therapeutic strategies targeting CK2 function. Overall, our study indicates that CK2 plays a critical role in CLL cell survival, laying the groundwork for the inclusion of CK2 inhibitors into future therapeutic strategies.

The bone morphogenic protein (BMP) antagonist gremlin is expressed during embryonic development and under different pathological conditions, including cancer. Gremlin is a pro-angiogenic protein belonging to the cystine-knot superfamily that includes transforming growth factor-beta proteins and the angiogenic vascular endothelial growth factors (VEGFs). Here, we demonstrate that gremlin binds VEGF receptor-2 (VEGFR2), the main transducer of VEGF-mediated angiogenic signals, in a BMP-independent manner. Similar to VEGF-A, gremlin activates VEGFR2 in endothelial cells, leading to VEGFR2-dependent angiogenic responses in vitro and in vivo. Gremlin thus represents a novel pro-angiogenic VEGFR2 agonist distinct from the VEGF family ligands with implications in vascular development, angiogenesis-dependent diseases, and tumor neovascularization.

To evaluate outcome and prognosis of patients with T-cell lymphoma we analyzed 343 patients treated within trials of the German High-Grade Non-Hodgkin's Lymphoma Study Group. 289 patients belonged to one of the four major T-cell lymphoma subtypes: anaplastic large cell lymphoma (ALCL), anaplastic large cell lymphoma kinase-positive (n = 78); ALCL, ALK-negative (n = 113); peripheral T-cell lymphoma, unspecified (PTCLU) (n = 70); and angioimmunoblastic T-cell lymphoma (AITL) (n = 28). Treatment consisted of 6-8 courses of CHOP or CHOE(etoposide)P. Three-year event-free and overall survival were 75.8% and 89.8% for patients with ALK-positive ALCL, 50.0% and 67.5% for patients with AITL, 45.7% and 62.1% for patients with ALK-negative ALCL, and 41.1% and 53.9% for patients with PTCLU. The International Prognostic Index was effective in defining risk groups with significantly different outcomes. For younger patients, (</= 60 years, LDH </= UNV) etoposide improved 3-year EFS: 75.4% vs. 51.0%, p = 0.003. The effect of etoposide showed only a trend (p=0.057) in subtypes other than ALCL, ALK-positive. In elderly patients (> 60 years) six courses of CHOP administered every 3 weeks remains the standard therapy. Patients with ALK-negative ALCL, PTCLU, or AITL presenting with IPI > 1 have a poor prognosis and should be considered candidates for novel treatment strategies. This is a retrospective analysis of seven studies: RICOVER-60 is registered through http://ClinicalTrials.gov as NCT00052936 and as EU-20243 The MegaCHOEP phase III study is registered through http://ClinicalTrials.gov as NCT00129090 The Hi-CHOEP phase III study is registered through http://ClinicalTrials.gov as NCT00053768 and as EU-20242 The NHL-B1, NHL-B2, Hi-CHOEP phase II, and MegaCHOEP phase II studies are too old, so they were not registered.

Granulysin (GNLY), an antimicrobial protein present in the granules of human cytotoxic T lymphocytes (CTL) and natural killer (NK) cells, is produced as an intact 15 kDa form that is cleaved to yield a 9 kDa form. Alarmins are endogenous mediators that can induce recruitment and activation of antigen-presenting cells (APCs), and consequently promote the generation of immune response. We hypothesized that GNLY might function as an alarmin. Here, we report that both 9- and 15-kDa forms of recombinant GNLY induced in vitro chemotaxis and activation of both human and mouse dendritic cells (DC), recruited inflammatory leucocytes including APCs in mice, and promoted antigen-specific immune responses upon co-administration with an antigen. GNLY-induced APC recruitment and activation required the presence of TLR4. The observed activity of recombinant GNLY was not due to endotoxin contamination. The capability of the supernatant of GNLY-expressing HuT78 cells to activate DC was blocked by anti-GNLY antibodies. Finally we present evidence that supernatants of degranulated human NK92 or primary NK cells also activated DCs in a GNLY- and TLR4-dependent manner, indicating the physiological relevance of our findings. Thus, GNLY is the first identified lymphocyte-derived alarmin capable of promoting APC recruitment, activation and antigen-specific immune response.

Engagement of T cells with antigen-presenting cells requires T cell receptor (TCR) stimulation at the immune synapse. We previously reported that TCR stimulation induces the release of cellular ATP that regulates T cell activation. Here we tested the roles of pannexin-1 hemichannels, which have been implicated in ATP release, and of various P2X receptors, which serve as ATP-gated Ca(2+) channels, in events that control T cell activation. TCR stimulation results in the translocation of P2X1 and P2X4 receptors and pannexin-1 hemichannels to the immune synapse, while P2X7 receptors remain uniformly distributed on the cell surface. Removal of extracellular ATP or inhibition, mutation, or silencing of P2X1 and P2X4 receptors inhibits Ca(2+) entry, NFAT activation, and induction of interleukin-2 synthesis. Inhibition of pannexin-1 hemichannels suppresses TCR-induced ATP release, Ca(2+) entry, and T cell activation. We conclude that pannexin-1 hemichannels and P2X1 and P2X4 receptors facilitate ATP release and autocrine feedback mechanisms that control Ca(2+) entry and T cell activation at the immune synapse.

Systematic reviews and meta-analyses are being increasingly used to summarize medical literature and identify areas where research is needed. Systematic reviews limit bias by using a reproducible scientific process to search the literature and evaluate the quality of the individual studies. If possible the results are statistically combined into a meta-analysis where the data are weighted and pooled to produce an estimate of effect. This article aims to provide the reader with a practical overview of systematic review and meta-analysis methodology, with a focus on the process of performing a review and the related issues at each step.

Following anti-retroviral therapy a significant proportion of HIV+ patients with mycobacterial co-infections develop a paradoxical and poorly understood inflammatory disease, termed Immune Reconstitution Inflammatory Syndrome (IRIS). Here we show that Mycobacterium avium infected T cell deficient mice injected with CD4 T cells also develop an immune reconstitution disease (IRD) manifesting as weight loss, impaired lung function and rapid mortality. This form of IRD requires Ag recognition and IFNgamma production by the donor CD4 T cells, and correlates with marked alterations in blood and tissue CD11b+ myeloid cells. Interestingly, disease is associated with impaired rather than augmented T cell expansion and function, and is not strictly dependent on lymphopenia induced T cell proliferation. Instead, our findings suggest that mycobacterial-associated IRIS results from a heightened sensitivity of infected lymphopenic hosts to the detrimental effects of Ag-driven CD4 T cell responses.

The clinical impact of FLT3-internal tandem duplications (ITD), an adverse prognostic marker in adults age <60 years with primary cytogenetically normal acute myeloid leukemia (CN-AML), requires further investigation in older patients. In CN-AML patients age >/=60 years treated on CALGB frontline trials, we found that FLT3-ITD remained associated with shorter disease-free [DFS; P<.001; hazard ratio (HR)=2.10] and overall survival (OS; P<.001; HR=1.97) in multivariable analyses. This impact on DFS and OS was in patients 60-69 (P<.001, each) rather than in those >/=70 years. A FLT3-ITD-associated gene-expression signature revealed overexpression of FLT3, homeobox genes (MEIS1, PBX3, HOXB3), and immunotherapeutic targets (WT1, CD33) and underexpression of leukemia-associated (MLLT3, TAL1) and erythropoiesis-associated (GATA3, EPOR, ANK1, HEMGN) genes. A FLT3-ITD-associated microRNA-expression signature included overexpressed miR-155 and underexpressed miR-144 and miR-451. FLT3-ITD identifies older CN-AML patients with molecular high-risk and is associated with gene- and microRNA-expression signatures that provide biologic insights for novel therapeutic approaches.

Long-term survival is now an expected outcome after hematopoietic cell transplantation (HCT). However, the burden of morbidity long-term after HCT remains unknown. We examined the magnitude of risk of chronic health conditions reported by 1022 HCT survivors, and their siblings (n=309). A severity score (grades 1 [mild] through 4 [life-threatening]) was assigned to each health condition using the Common Terminology Criteria for Adverse Events (v3). Sixty-six percent of the HCT survivors reported at least one chronic condition; 18% reported severe/life-threatening conditions; comparable figures in siblings were 39% and 8%, respectively (p<0.001). The cumulative incidence of a chronic health condition among HCT survivors was 59% (95% CI, 56%-62%) at 10 years after HCT; for severe/life-threatening conditions or death due to chronic health conditions, the 10-year cumulative incidence approached 35% (95%CI, 32%-39%). HCT survivors were 2 times as likely as siblings to develop a chronic condition (95% CI, 1.6-2.1), and 3.5 times to develop severe/life threatening conditions (95% CI, 2.3-5.4). HCT survivors with chronic graft versus host disease were 4.7 times as likely to develop severe/life threatening conditions (95% CI, 3.0-7.2). The burden of long-term morbidity borne by HCT survivors is substantial, and long-term follow-up of patients who received transplantation is recommended.

Influenza causes excess morbidity in sickle cell disease (SCD). H1N1 pandemic influenza has been severe in children. To compare H1N1 versus seasonal influenza in SCD (<22-year-olds), we reviewed medical records (1993-2009). We identified 123 cases of laboratory-confirmed influenza (94 seasonal; 29 H1N1). Those with seasonal influenza were younger (median 4.4 vs. 8.7 years, p=0.006) and had less asthma (24% vs. 56%, p=0.002). Those with H1N1 influenza more often had acute chest syndrome (ACS, 34% vs. 13%, p=0.01) and required intensive care (17% vs. 3%, P=0.02), including mechanical ventilation (10% vs. 0%, p=0.02). In multivariate analysis, older age [odds ratio (OR) 1.1 per year, p=0.04] and H1N1 influenza (OR 3.0, p=0.04) were associated with ACS, and older age (OR 1.1 per year, p=0.02) and prior ACS (OR 3.3 per episode in last year, p <0.006) with intensive care. Influenza, especially H1N1, causes critical illness in SCD and should be prevented.

The Philadelphia (Ph) chromosome is present in approximately 20-30% of adults with acute lymphoblastic leukaemia (ALL). The poor prognosis of this relatively uncommon acute leukemia has led to the rapid adoption of treatment strategies such as unrelated donor haematopoietic stem cell transplant and tyrosine kinase inhibitors into clinical practice, despite a relative paucity of randomised clinical trials. Recently, there has been a surge of interest in the underlying biology of ALL. In combination with an accumulation of more mature clinical study data in Ph+ ALL, it is increasingly possible to make more rational and informed treatment choices for patients of all ages. In this article, I review available data and indicate how I personally interpret current evidence to make pragmatic treatment choices with my patients, outside of clinical trials. My strongest recommendation is that all physicians treating this rare disease actively seek appropriate clinical trials for their patients, wherever possible.