The term monoclonal gammopathy of renal significance (MGRS) was introduced by the International Kidney and Monoclonal Gammopathy Research Group (IKMG) in 2012. The IKMG met in April 2017 to refine the definition of MGRS and to update the diagnostic criteria for MGRS-related diseases. Accordingly , in this Expert Consensus Document, the IKMG redefines MGRS as a clonal proliferative disorder that produces a nephrotoxic monoclonal immunoglobulin and does not meet previously defined haematological criteria for treatment of a specific malignancy. The diagnosis of MGRS-related disease is established by kidney biopsy and immunofluorescence studies to identify the monotypic immunoglobulin deposits (although these deposits are minimal in patients with either C3 glomerulopathy or thrombotic microangiopathy). Accordingly , the IKMG recommends a kidney biopsy in patients suspected of having MGRS to maximize the chance of correct diagnosis. Serum and urine protein electrophoresis and immunofixation, as well as analyses of serum free light chains, should also be performed to identify the monoclonal immunoglobulin, which helps to establish the diagnosis of MGRS and might also be useful for assessing responses to treatment. Finally , bone marrow aspiration and biopsy should be conducted to identify the lymphoproliferative clone. Flow cytometry can be helpful in identifying small clones. Additional genetic tests and fluorescent in situ hybridization studies are helpful for clonal identification and for generating treatment recommendations. Treatment of MGRS was not addressed at the 2017 IKMG meeting; consequently , this Expert Consensus Document does not include any recommendations for the treatment of patients with MGRS.

Cells with endothelial phenotype generated from adult peripheral blood have emerging diagnostic and therapeutic potential. This study examined the lineage relationship between, and angiogenic function of, early endothelial progenitor cells (EPCs) and late outgrowth endothelial cells (OECs) in culture. Culture conditions were established to support the generation of both EPCs and OECs from the same starting population of peripheral blood mononuclear cells (PBMCs). Utilizing differences in expression of the surface endotoxin receptor CD14, it was determined that the vast majority of EPCs arose from a CD14 ؉ subpopulation of PBMCs but OECs developed exclusively from the CD14 ؊ fraction. Human OECs, but not EPCs, expressed key regulatory proteins endothelial nitric oxide synthase (eNOS) and caveolin-1. Moreover, OECs exhibited a markedly greater capacity for capillary morphogenesis in in vitro and in vivo matrigel models, tube formation by OECs being in part dependent on eNOS function. Collectively, these data indicate lineage and functional heterogeneity in the population of circulating cells capable of assuming an endothelial phenotype and provide rationale for the investigation of new celltherapeutic approaches to ischemic cardiovascular disease.

(Table 1). Definitive quantitative assays include calibrators fit to a regression model to calculate absolute values and reference standards that are well characterized and fully representative of the endogenous measurand. Definitive quantitative assays can be both accurate and precise. Relative quantitative assays utilize responseconcentration calibration, however in this scenario the reference standards are not fully characterized or truly representative of the endogenous measurand. As such, imprecision can be demonstrated for a relative quantitative method, but accuracy can only be estimated. With quasi-quantitative assays there is a relationship between the response and the measurand but calibration standards are not used. Thus, quasi-quantitative methods can be validated for imprecision, but not accuracy. Qualitative methods generate categorical data. Flow cytometric methods largely fall in the two latter categories and are essentially therefore quasi-quantitative or qualitative.Multi-color flow cytometry is a unique technology, which enables the analysis of heterogeneous cellular systems and provides multiparametric information at a cellby-cell level. The strength of flow cytometry lies not only in the ability to simultaneously measure multiple parameters, but also in the flexibility to report them in different ways. The appropriate data output depends on the biology of the system being investigated, the analytical or scientific question being asked, and the intended use of the results. A wide variety of data outputs can be reported usually expressed in terms of several characteristics of cells, or cell subsets, in the sample tested for example, percentage of positive events, absolute counts, median fluorescence intensity, quantitative antigen expression levels, ratiometric indices, markers coexpression, or relative nucleic acid content.

Plasma membrane microdomains containing sphingolipids and cholesterol (lipid rafts) are enriched in signaling molecules. The cross-linking of certain types of cell surface receptors initiates the redistribution of these lipid rafts, resulting in the formation of signaling complexes. However, little is known about the regulation of the initial raft redistribution and whether negative regulatory signaling pathways target this phase of cellular activation. We used natural killer (NK) cells as a model to investigate the regulation of raft redistribution, as both positive and negative signals have been implicated in the development of their cellular function. Here we show that after NK cells form conjugates with sensitive tumor cells, rafts become polarized to the site of target recognition. This redistribution of lipid rafts requires the activation of both Src and Syk family protein tyrosine kinases. In contrast, engagement of major histocompatibility complex (MHC)-recognizing killer cell inhibitory receptors (KIRs) on NK cells by resistant, MHC-bearing tumor targets blocks raft redistribution. This inhibition is dependent on the catalytic activity of KIR-associated SHP-1, a Src homology 2 (SH2) domain containing tyrosine phosphatase. These results suggest that the influence of integrated positive and negative signals on raft redistribution critically influences the development of cell-mediated cytotoxicity.

Background-Bone marrow-derived cells have been shown to contribute to endothelial replacement after vascular injury.In vitro culture of peripheral blood mononuclear cells produces cells with phenotypic characteristics of endothelium. To test the hypothesis that delivery of autologous culture-modified mononuclear cells (CMMCs) to injured arteries could attenuate the vascular response to injury, a rabbit model was studied. Methods and Results-Rabbit peripheral blood mononuclear cells were cultured in endothelial growth media for 7 to 12 days, yielding highly proliferative cells with distinct endothelial phenotype (expressing CD31 and endothelial nitric oxide synthase and capable of acetylated LDL uptake). A rabbit model of balloon carotid injury was used to evaluate the effect of day 7 CMMC delivery on vascular responses. Animals underwent balloon injury and immediate delivery of autologous CMMCs or buffered saline by 20 minutes of local dwelling. Fluorescence-labeled CMMCs were detected in all vessel layers 4 weeks after delivery. Colonies of cells that localized to the lumen and stained for endothelial markers were also identified. Local CMMC administration at the time of balloon injury accelerated reendothelialization at 4 weeks compared with saline (PϽ0.05). Moreover, CMMC delivery markedly improved endothelium-dependent vasoreactivity at 4 weeks compared with saline (PϽ0.005). Finally, CMMC treatment reduced neointimal formation by 55% at 4 weeks (PϽ0.05). Conclusions-These data demonstrate that delivery of CMMCs to balloon-injured arteries is associated with accelerated reendothelialization, enhanced endothelium-dependent vasoreactivity, and reduced neointimal formation. Thus, delivery of autologous CMMCs represents a novel vasculoprotective approach to attenuate the response to acute vascular injury.

No abstract

Stimulation of lymphocytes through multichain immune recognition receptors activates multiple signaling pathways. Adaptor proteins play an important role in integrating these pathways by their ability to simultaneously bind multiple signaling components. Recently, the 3BP2 adaptor protein has been shown to positively regulate the transcriptional activity of T cells. However, the mechanisms by which signaling components are involved in this regulation remain unclear, as does a potential role for 3BP2 in the regulation of other cellular functions. Here we describe a positive regulatory role for 3BP2 in NK cell-mediated cytotoxicity. We also identify p95vav and phospholipase C-γ isoforms as binding partners of 3BP2. Our results show that tyrosine-183 of 3BP2 is specifically involved in this interaction and that this residue critically influences 3BP2-dependent function. Therefore, 3BP2 regulates NK cell-mediated cytotoxicity by mobilizing key downstream signaling effectors.

Activation of immune system cells via antigen-, Fc-, or natural killer cell-triggering-receptor stimulation is aborted by co-engagement of inhibitory receptors. Negative signaling by killer cell inhibitory receptors and related receptors depends on the Src homology 2 (SH2)-containing protein tyrosine phosphatase SHP-1. Using a combination of direct binding and functional assays, we demonstrated that the SH2 domain-containing leukocyte protein 76 (SLP-76) is a specific target for dephosphorylation by SHP-1 in T cells and natural killer cells. Furthermore, we showed that tyrosine-phosphorylated SLP-76 is required for optimal activation of cytotoxic lymphocytes, suggesting that the targeted dephosphorylation of SLP-76 by SHP-1 is an important mechanism for the negative regulation of immune cell activation by inhibitory receptors.Initiation, prevention, and termination of immune responses are governed by receptors that transduce signals from the exterior to the interior of hematopoietic cells. The proximal intracellular biochemical events initiated following stimulation of antigen, Fc-, and NK 1 cell triggering receptors include activation of Src and Syk family protein tyrosine kinases (PTKs), hydrolysis of membrane phospholipids, and mobilization of intracellular calcium (1-4). This activation pathway is subject to negative regulation by inhibitory receptors. For example, class I major histocompatibility complex (MHC)-recognizing KIRs prevent NK cells and certain subpopulations of T cells from killing specific class I MHC-bearing target cells (5-8).KIRs belong to a large family of immune cell inhibitory receptors that contain a conserved immunoreceptor tyrosinebased inhibitory motif (ITIM) in their cytoplasmic signaling domains (9 -11). Tyrosine phosphorylation of the ITIM results in the recruitment of SH2 domain-containing phosphatases, such as the PTPs SHP-1 and SHP-2 or the SH2-containing inositol phosphatase SHIP (12-16). These two classes of phosphatases deliver distinct inhibitory signals. SH2-containing inositol phosphatase recruited to the inhibitory receptor Fc␥RIIB acts relatively late in the activation cascade by interfering with sustained calcium influx (17,18). In contrast, SHP-1 recruited to KIRs inhibits the earliest FcR-initiated signals, including tyrosine phosphorylation of the immunoreceptor tyrosine-based activation motif-containing -subunits of Fc␥RIIIA and the downstream effectors zeta-associated protein-70 (ZAP-70) and phospholipase C-␥ (12), and also inhibits the activation of p36 induced by natural killing (19). Due to the prominent role of protein tyrosine phosphorylation in early signal output from multisubunit immune recognition receptors, the field of candidate SHP-1 substrates is large. SHP-1-utilizing inhibitory receptors negatively regulate similar Src and Syk family PTK-dependent activation pathways in a variety of hematopoietic cell types (9 -11), however, suggesting that a common SHP-1 target may potentially exist. We therefore sought to identify a direct target of SHP-1 using KIR...