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Caloric restriction (CR) is the leading non-pharmacological intervention to delay induced and spontaneous tumors in pre-clinical models. These effects of CR are largely attributed to canonical inhibition of pro-growth pathways. However, our recent data suggest that CR impairs primary tumor growth and cancer progression in the murine 4T1 model of triple negative breast cancer (TNBC), at least in part, through reduced frequency of the myeloid-derived suppressor cells (MDSC). In the present study, we sought to determine whether injection of excess MDSCs could block regression in 4T1 tumor growth and metastatic spread in BALB/cJ female mice undergoing daily CR. Our findings show that MDSC injection impeded CR-mediated protection against tumor growth without increasing lung metastatic burden. Overall, these results reveal that CR can slow cancer progression by affecting immune suppressive cells.

This paper presents two complementary approaches for simulating the thermal performance of borehole thermal energy storage (BTES) systems. The first approach uses the concepts of heat exchange and storage efficiencies as a function of the state-of-charge of the BTES. The second method employs a technique similar to thermal response factors used to model bore fields in ground-source heat pump systems. It utilizes non-dimensional average storage temperatures and bore field thermal resistances of the BTES over time. The two methods rely on numerical experiments to obtain the required performance curves. As shown through examples, the two approaches are relatively simple to use, and it is shown that they are in good agreement with the well-known duct ground storage model. In one of the examples, it is suggested that the design of a BTES could be performed using three successive thermal pulses, similar to the approach used to determine the length of vertical ground heat exchangers in a ground-source heat pump systems.

Resveratrol improves healthspan and lifespan in many organisms. Several different targets and mechanisms of action have been proposed to explain the beneficial effects of resveratrol on healthspan and longevity, including the activation of a family of proteins known as sirtuins and its action as a calorie restriction mimetic. In this mini-review, we discuss some of the most recent findings to date in the resveratrol field and suggest three areas of future research based on those results.

The prevention or delay of the onset of age-related diseases prolongs survival and improves quality of life while reducing the burden on the health care system. Activation of sirtuin 1 (SIRT1), an NAD+-dependent deacetylase, improves metabolism and confers protection against physiological and cognitive disturbances in old age. SRT1720 is a specific SIRT1 activator that has health and lifespan benefits in adult mice fed a high-fat diet. We found extension in lifespan, delayed onset of age-related metabolic diseases, and improved general health in mice fed a standard diet after SRT1720 supplementation. Inhibition of proinflammatory gene expression in both liver and muscle of SRT1720-treated animals was noted. SRT1720 lowered the phosphorylation of NF-κB pathway regulators in vitro only when SIRT1 was functionally present. Combined with our previous work, the current study further supports the beneficial effects of SRT1720 on health across the lifespan in mice.

The orphan nuclear receptor estrogen-related receptor alpha (ERRα) directs the transcription of nuclear genes involved in energy homeostasis control and the regulation of mitochondrial mass and function. A crucial role for controlling ERRα-mediated target gene expression has been ascribed to the biarylpyrazole compound 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperidinyl-1H-pyrazole-3-carboxamide (AM251) through direct binding to and destabilization of ERRαprotein. Here, we provide evidence that structurally related AM251 analogs also have negative impacts on ERRαprotein levels in a cell-type-dependent manner while having no deleterious actions on ERRγ. We show that these off-target cellular effects of AM251 are mediated by proteasomal degradation of nuclear ERRα. Cell treatment with the nuclear export inhibitor leptomycin B did not prevent AM251-induced destabilization of ERRαprotein, whereas proteasome inhibition with MG132 stabilized and maintained its DNA-binding function, indicative of ERRαbeing a target of nuclear proteasomal complexes. NativePAGE analysis revealed that ERRαformed a ∼220-kDa multiprotein nuclear complex that was devoid of ERRγand the coregulator peroxisome proliferator-activated receptor γcoactivator-1. AM251 induced SUMO-2,3 incorporation in ERRαin conjunction with increased protein kinase C activity, whose activation by phorbol ester also promoted ERRαprotein loss. Down-regulation of ERRαby AM251 or small interfering RNA led to increased mitochondria biogenesis while negatively impacting mitochondrial membrane potential. These results reveal a novel molecular mechanism by which AM251 and related compounds alter mitochondrial physiology through destabilization of ERRα.

Inhibition of cell proliferation by fenoterol and fenoterol derivatives in 1321N1 astrocytoma cells is consistent with β(2)-adrenergic receptor (β(2)-AR) stimulation. However, the events that result in fenoterol-mediated control of cell proliferation in other cell types are not clear. Here, we compare the effect of the β(2)-AR agonists (R,R')-fenoterol (Fen) and (R,R')-4-methoxy-1-naphthylfenoterol (MNF) on signaling and cell proliferation in HepG2 hepatocarcinoma cells by using Western blotting and [(3)H]thymidine incorporation assays. Despite the expression of β(2)-AR, no cAMP accumulation was observed when cells were stimulated with isoproterenol or Fen, although the treatment elicited both mitogen-activated protein kinase and phosphatidylinositol 3-kinase/Akt activation. Unexpectedly, isoproterenol and Fen promoted HepG2 cell growth, but MNF reduced proliferation together with increased apoptosis. The mitogenic responses of Fen were attenuated by 3-(isopropylamino)-1-[(7-methyl-4-indanyl)oxy]butan-2-ol (ICI 118,551), a β(2)-AR antagonist, whereas those of MNF were unaffected. Because of the coexpression of β(2)-AR and cannabinoid receptors (CBRs) and their impact on HepG2 cell proliferation, these Gα(i)/Gα(o)-linked receptors may be implicated in MNF signaling. Cell treatment with (R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-napthalenylmethanone (WIN 55,212-2), a synthetic agonist of CB(1)R and CB(2)R, led to growth inhibition, whereas inverse agonists of these receptors blocked MNF mitogenic responses without affecting Fen signaling. MNF responses were sensitive to pertussis toxin. The β(2)-AR-deficient U87MG cells were refractory to Fen, but responsive to the antiproliferative actions of MNF and WIN 55,212-2. The data indicate that the presence of the naphthyl moiety in MNF results in functional coupling to the CBR pathway, providing one of the first examples of a dually acting β(2)-AR-CBR ligand.

Members of the heat shock protein-90 (Hsp90) family are key regulators of biological processes through dynamic interaction with a multitude of protein partners. However, the transient nature of these interactions hinders the identification of Hsp90 interactors. Here we show that chemical cross-linking with ethylene glycolbis (succinimidylsuccinate), but not shorter cross-linkers, generated an abundant 240-kDa heteroconjugate of the molecular chaperone Hsp90 in different cell types. The combined use of pharmacological and genetic approaches allowed the characterization of the subunit composition and subcellular compartmentalization of the multimeric protein complex, termed p240. The in situ formation of p240 did not require the N-terminal domain or the ATPase activity of Hsp90. Utilizing subcellular fractionation techniques and a cell-impermeant cross-linker, subpopulations of p240 were found to be present in both the plasma membrane and the mitochondria. The Hsp90-interacting proteins, including Hsp70, p60Hop and the scaffolding protein filamin A, had no role in governing the formation of p240. Therefore, chemical cross-linking combined with proteomic methods has the potential to unravel the protein components of this p240 complex and, more importantly, may provide an approach to expand the range of tools available to the study of the Hsp90 interactome.

Interleukin-6 (IL-6) is a proinflammatory cytokine that exerts a wide range of cellular, physiological, and pathophysiological responses. Pyrrolidine dithiocarbamate (PDTC) antagonizes the cellular responsiveness to IL-6 through impairment in signal transducer and activator of transcription-3 activation and downstream signaling. To further elucidate the biological properties of PDTC, global gene expression profiling of human HepG2 hepatocellular carcinoma cells was carried out after treatment with PDTC or IL-6 for up to 8 h. Through an unbiased pathway analysis method, gene array analysis showed dramatic and temporal differences in expression changes in response to PDTC versus IL-6. A significant number of genes associated with metabolic pathways, inflammation, translation, and mitochondrial function were changed, with ribosomal protein genes and DNA damage-inducible transcript 4 protein (DDIT4) primarily up-regulated with PDTC but down-regulated with IL-6. Quantitative polymerase chain reaction and Western blot analyses validated the microarray data and showed the reciprocal expression pattern of the mammalian target of rapamycin (mTOR)-negative regulator DDIT4 in response to PDTC versus IL-6. Cell treatment with PDTC resulted in a rapid and sustained activation of Akt and subsequently blocked the IL-6-mediated increase in mTOR complex 1 function through up-regulation in DDIT4 expression. Conversely, down-regulation of DDIT4 with small interfering RNA dampened the capacity of PDTC to block IL-6-dependent mTOR activation. The overall protein biosynthetic capacity of the cells was severely blunted by IL-6 but increased in a rapamycin-independent pathway by PDTC. These results demonstrate a critical effect of PDTC on mTOR complex 1 function and provide evidence that PDTC can reverse IL-6-related signaling via induction of DDIT4.

Abstract: Activation of the glucagon-like peptide-1 (GLP-1) receptor on pancreatic beta cells by GLP-1 and exendin-4 (a more potent and stable agonist of the GLP-1 receptor than GLP-1) increases insulin secretion. Exendin-4 is 39 amino acids long, unlike GLP-1 which has 30 amino acids. Because of its non-mammalian (lizard) origin and unique C-terminal sequence, exendin-4 may be immunogenic in humans. We showed previously that the C terminally truncated exendin peptide exendin (1–30) has a reduced affinity for the GLP-1 receptor and a diminished ability to increase intracellular cAMP in insulinoma cells. Here we show that daily intraperitoneal injection of exendin (1–30) (1 nmol/kg) for 20 d followed by 31 d twice daily to Lepr db/Leprdb (db/db) mice significantly reduced the amount of visceral fat relative to saline-treated controls and improved HbA1C (control 9.5±0.2% vs treated 7.9±0.2%, p=0.001) but was not as effective as exendin-4. To examine the ability of exendin (1–30) to stimulate beta-cell growth, we injected one group of 3-mo-old Fisher rats with exendin (1–30) (1 nmol/kg) and another group with saline for 8 d. We observed no change in beta-cell area, but did see a change in the number of islets with nuclei positive for BrdU [10.7±1.8% exendin (1–30) vs 6.5±0.5% control].

Abstract: Insulin receptor signal transduction plays a critical role in regulating pancreatic β-cell function, notably the acute first-phase insulin release in response to glucose. The basis for insulin resistance in pancreatic β-cells is not well understood but may be related to abnormal regulation of tyrosine phosphorylation events, which, in turn, may alter organization of insulin-signaling molecules in space and time. Members of the protein tyrosine phosphatase (PTPase) family are both functionally and structurally diverse; and within the past few years data have emerged from many laboratories that suggest selectivity of the PTPase catalytic domains toward cellular substrates. Of significance, a subset of PTPases has been implicated in the regulation of insulin signaling in a number of insulin-sensitive tissues. Alteration in PTPase expression or activity has been associated with abnormal regulation of tyrosine phosphorylation events and is accompanied by modulation of insulin sensitivity in vivo. Manipulations aimed at reducing expression of physiologically relevant PTPases acting at a step proximal to the insulin receptor are accompanied by normalization of blood glucose levels and improved insulin sensitivity in both normal and diabetic animals. Hence, the development of tissue-specific gene inactivation strategies should facilitate the study of the potential role of PTPases in β-cell insulin signaling transduction.

Abstract: Insulin receptor signal transduction plays a critical role in regulating pancreatic β-cell function, notably the acute first-phase insulin release in response to glucose. The basis for insulin resistance in pancreatic β-cells is not well understood, but may be related to abnormal regulation of tyrosine phosphorylation events, which, in turn, may alter organization of insulin-signaling molecules in space and time. Members of the protein tyrosine phosphatase (PTPase) family are both functionally and structurally diverse; and within the past few years data have emerged from many laboratories that suggest selectivity of the PTPase catalytic domains toward cellular substrates. Of significance, a subset of PTPases has been implicated in the regulation of insulin signaling in a number of insulin-sensitive tissues. Alteration in PTPase expression or activity has been associated with abnormal regulation of tyrosine phosphorylation events and is accompanied by modulation of insulin sensitivity in vivo. Manipulations aimed at reducing expression of physiologically relevant PTPases acting at a step proximal to the insulin receptor are accompanied by normalization of blood glucose levels and improved insulin sensitivity in both normal and diabetic animals. Hence, the development of tissue-specific gene inactivation strategies should facilitate the study of the potential role of PTPases in β-cell insulin signaling transduction.

We assess the degree of phenotypic variation in a cohort of 24-month-old male C57BL/6 mice. Because murine studies often use small sample sizes, if the commonly relied upon assumption of a normal distribution of residuals is not met, it may inflate type I error rates. In this study, 3–20 mice are resampled from the empirical distributions of 376 mice to create plasmodes, an approach for computing type I error rates and power for commonly used statistical tests without assuming a normal distribution of residuals. While all of the phenotypic and metabolic variables studied show considerable variability, the number of animals required to achieve adequate power is markedly different depending on the statistical test being performed. Overall, this work provides an analysis with which researchers can make informed decisions about the sample size required to achieve statistical power from specific measurements without a prioriassumptions of a theoretical distribution.

SummaryThis paper summarises the guidelines and recommendations that were generated during a number of discussion forums attended by the majority of Belgian cytometry laboratory professionals. These forums focused on the rational and optimal use of flow cytometric evaluations in the clinical laboratory setting. The aim was to improve the coherence of the testing panels and the quality of the results and -as such-the clinical diagnostic information. It was also the aim to provide the Belgian prescribing physician and interested laymen with an updated overview of the flow cytometric possibilities. Emphasis is placed on immunophenotyping of haematological malignancies, hematopoietic progenitor cell counting and follow-up of the viral infection caused by the human immunodeficiency virus.

The utility and validity of Bandura's self-efficacy construct was evaluated in a study involving 62 volunteer overweight women. Pretreatment, posttreatment, and follow-up assessments of self-efficacy and weight loss were obtained in the context of a behaviorally oriented weight-reduction program. It was predicted that (a) weight loss would be related to enhancement in personal efficacy, (b) posttreatment efficacy would be a significant and more accurate predictor of weight loss during follow-up intervals than posttreatment weight loss, and (c) self-efficacy would be related to attrition whereas weight loss would not. Results indicate a significant relationship between weight change and personal efficacy during the follow-up intervals. In accord with Bandura's theory, efficacy expectations predicted outcome during the 6-week and 6-month follow-up intervals, whereas posttreatment weight loss was unrelated to later outcome. In addition, completers had a substantially higher level of personal efficacy than dropouts over treatment and, to a lesser extent, over the follow-up period. Some procedural considerations regarding the assessment of personal efficacy are raised, and the relationship between the cognitively based constructs of goal choice and self-efficacy and task performance are discussed. Finally, given the nature and variability of weight-reduction efforts and the overall time span of the study, it is concluded that results attest to the validity and utility of the self-efficacy construct in predicting behavioral persistence and level of behavioral change.

The role of the insulin receptor COOH-terminal domain in the regulation of insulin signal transduction was explored with a variety of synthetic peptides. One of the peptides, termed peptide HC, whose structure corresponds to residues 1293-1307 of the insulin proreceptor sequence, enhanced insulin-stimulated autophosphorylation of the insulin receptor in cell-free systems and in semipermeabilized Chinese hamster ovary (CHO) cells that had been transfected with an expression plasmid encoding the human insulin receptor (CHO/HIRc) at concentrations where there was no detectable effect on basal autophosphorylation levels or on receptor dephosphorylation. A lipophilic analogue of peptide HC, stearyl peptide HC, added to intact CHO/HIRc cells enhanced significantly insulin-stimulated insulin receptor autophosphorylation while having no effect on ligand-stimulated receptor phosphorylation in CHO cells overexpressing either the IGF-1 receptor or epidermal growth factor receptor. Addition of stearyl peptide HC to CHO/HIRc cells resulted in a 2.4 ± 0.3-fold increase in the amount of insulin-stimulated phosphatidylinositol 3-kinase detected in anti-IRS-1 immunoprecipitates and a 2.1 ± 0.6-fold increase in the levels of tyrosine phosphorylation of mitogen-activated protein kinase in response to insulin. Finally, a derivative of peptide HC coupled to a biotin moiety was prepared and showed to bind with the β-subunit of the wild-type insulin receptor and a truncated receptor that lacks 43 amino acids from its carboxyl terminus. However, there was little binding, if any, of the peptide with the IGF-1 receptors or the epidermal growth factor receptors. Taken together, our data demonstrate that a pentadecapeptide related to the carboxyl terminus of the insulin receptor binds to the insulin receptor β-subunit and that this interaction may contribute to the increased receptor's intrinsic activity and signal transduction.

Immunophenotyping has become an important tool in the diagnosis of acute leukemia for several reasons. Indeed the use of a standardized panel of monoclonal antibodies (MoAb) to B and T cells, and myeloid cells, as well as non lineage restricted antigens, permits allocation of more than 98% of acute leukemia to their respective lineage.1-3 In ALL, immunophenotyping has established a basis for precise and biologically oriented classification of the disease which may be of prognostic importance.2 In AML immunological markers are particularly important for identification of acute leukemia with minimal myeloid, erythroblastic or megakaryoblastic differentiation.Immunological markers also allow the identification of acute leukemias with minimal or aberrant marker expression, acute biphenotypic leukemia in which single cells coexpress different lineage associated markers and acute bilineage leukemia where there are two separate blast cell populations (usually lymphoid and myeloid).3There is sometimes confusion in the literature about the definition of acute unclassifiable and acute undifferentiated leukemia.4-6 This is mainly due to misinterpretation of phenotypic data or to the lack of relevant lineage specific markers in these studies, especially for the detection of cytoplasmic antigens. Indeed, it is important to stress that in hematopoietic precursors, antigens detected by monoclonal antibodies first appear in the cytoplasm during early differentiation and are only expressed on the membrane later. This has been demonstrated not only for the T lineage (Cy CD3). the B lineage (CyCD22) but also for the myeloid lineage (CYCD13).7,8 For all these reasons, it seems reasonable to consider that acute leukemia unclassifiable by morphocytochemical evaluation and standard membrane markers immunotyping includes at least: acute truly undifferentiated leukemia, acute minimally differentiated myeloid leukemia and acute true biphenotypic leukemia.5 We will discuss here, the immunological definition of the MO AML and AUL.

Expression of DNA repair enzymes, which includes ERCC-1, might be under the control of hormonal and growth factor stimulation. In the present study it was observed that insulin increased ERCC-1 mRNA levels both in Chinese hamster ovary cells overexpressing human insulin receptors (HIRc cells) and in fully differentiated 3T3-L1 adipocytes. To investigate the mechanisms underlying the increase in ERCC-1 gene expression in HIRc cells, we used a variety of pharmacological tools known to inhibit distinct signalling pathways. None of these inhibitors affected the amount of ERCC-1 mRNA in unstimulated cells. The pretreatment of cells with two chemically unrelated phosphatidylinositol 3´-kinase inhibitors, wortmannin and LY294002, failed to block the doubling of ERCC-1 mRNA content by insulin. Similarly, inhibition of pp70 S6 kinase by rapamycin had no apparent effects on this insulin response. In contrast, altering the p21ras-dependent pathway with either manumycin, an inhibitor of Ras farnesylation, or PD98059, an inhibitor of the mitogen-activated protein kinase/extracellular signal-regulated protein kinase (ERK) kinase, suppressed the induction of ERCC-1 mRNA by insulin (P< 0.001). Furthermore inhibition of RNA and protein synthesis negatively regulated the expression of this insulin-regulated gene (P< 0.005). These results suggest that insulin enhances ERCC-1 mRNA levels by the activation of the Ras–ERK-dependent pathway without the involvement of the phosphatidylinositol 3´-kinase/pp70 S6 kinase.

The expression of ERCC1, a member of the nucleotide excision repair (NER) family, is enhanced in cells transfected with insulin-like growth factor 1 (IGF-1) receptors. Of interest, an excellent concordance between ERCC1 expression and NER-mediated cell survival has been demonstrated. The two aims of the present study were to determine the signaling pathways used by IGF-1 to confer protection against apoptotic cell death in Chinese hamster ovary (CHO) cells and to assess the role of NER in this IGF-1 action. Experiments with pharmacological inhibitors indicated that phosphatidylinositol 3-kinase (PI 3-kinase) but not mitogen-activated protein kinase (ERK1/ERK2) mediates IGF-1 antiapoptotic activity. Using two series of CHO cells that have altered expression of ERCC1 or XPB/ERCC3, we examined IGF-1's ability to delay apoptotic death and reduction of mitochondrial oxidative function mediated by growth factor withdrawal. IGF-1 effectively blocked apoptosis, concomitant with increased MTT activity, in a pair of CHO cell lines expressing inactive ERCC1 (43-3B cells) and the transfected line of the mutant carrying the expressed human ERCC1 gene (83-G5 cells). Similarly, repair-deficient UV24 cells, which lack XPB/ERCC3, and their parental line AA8 were also responsive to the IGF-1's antiapoptotic capacity. In the presence of IGF-1, these cell lines became resistant to the cleavage of poly(ADP-ribose) polymerase, a key player in DNA damage recognition and DNA repair. These results suggest that PI 3-kinase activation plays a determinant role in the antiapoptotic function of IGF-1, but that functional NER does not play a critical part in mediating this IGF-1 response.

The steroidogenic capacity of purified immature porcine Leydig cells in culture was studied over several days. The cells were obtained by fractionating crude testicular interstitial cell suspensions on a discontinuous Percoll gradient (d = 1.037, 1.042, 1.052, 1.098 g/ml), and characterized by specific binding of 125I-human chorionic gonadotropin (hCG), testosterone (T) and cyclic adenosine 3′:5′-monophosphate (cAMP) production in response to hCG, and the enzymatic determination of Δ5-3β-hydroxysteroid dehydrogenase (3β-HSD) activity. The Leydig cells were recovered in a density band between 1.052–1.068 g/ml and grown in a chemically defined medium (Mather et al., 1981). In the absence of hCG, T production was low throughout the 6 days of culture. However, in response to hCG (10 mIU/ml), the cultured Leydig cells showed a progressive increase in T synthesis, which reached a maximum at Days 3–4 . 8-Br-cAMP (1 mM) induced a comparable rise in T production to that obtained with hCG throughout the culture period. In contrast, 8-Br-cAMP induced a near maximal increase in dehydroepiandrosterone (DHEA) production from Day 1. This paper demonstrates that purified immature porcine Leydig cells in primary culture are a valuable model to study the ontogeny of Leydig cell function.

The NMR properties of solid3He, mainly the ratio of the heat capacities of exchange and Zeeman energies and the exchange-lattice relaxation times are very sensitive to the presence of4He impurities, while the transverse relaxation timeT2 does not depend on the impurity concentration when the latter remains small. These properties can be explained in two different ways. (1) We assume an enhancement of exchange interactions around4He impurities. We derive the consequences of such an assumption and compare them with experimental results. For two molar volumes in the bcc phase, the locally enhanced exchange is equal to approximately7J, withJ being the exchange in pure3He. (2) Guyer and Zane introduce a mass fluctuation wave to explain the excess of heat capacity and the dependence of the longitudinal relaxation time with concentration. Both these models give rise to a four-energy bath system. As in the bcc phase, the exchange-lattice relaxation time in the hcp phase decreases when × increases at low enough4He concentrations. ForV=18.48 cm3 we deduce the coefficient for translational diffusion from high-temperature experiments with the help of Torrey's theory for spin-lattice relaxation.

Metabolic reprogramming of muscle stem cells modulates myogenic cell fate. In this issue of Cell Stem Cell, Ryall et al. (2015)show that SIRT1, a NAD+-dependent histone deacetylase, acts as an epigenetic regulator that connects changes in satellite cell metabolism with changes in the transcriptional machinery toward myogenic commitment.

Introduction: Natural Killer (NK) cells play a key role in defense against tumor cells that have the capacity to downregulate Human Leukocyte Antigen (HLA) class I expression. It has been reported that leukemic cells can have down-regulated expression of HLA class I molecules. Apparently, the NK cells of these patients are not able to destroy these leukemic cells and may allow malignant cells to escape from innate immune control. This failure may be due to the fact that NK cells are part of the malignant clone and therefore might have a decreased function. An alternative hypothesis could be that these patients may display a NK cell Receptor (NKR) genotype incapable of destroying leukemic cells with aberrant expression of HLA class I molecules. The polymorphic nature of the NKR genes generates diverse repertoires in the human population, which display specificity in the innate immune response.

Introduction: Natural Killer (NK) cells play a key role in defense against tumor cells that have the capacity to downregulate Human Leukocyte Antigen (HLA) class I expression. It has been reported that leukemic cells can have down-regulated expression of HLA class I molecules. Apparently, the NK cells of these patients are not able to destroy these leukemic cells and may allow malignant cells to escape from innate immune control. This failure may be due to the fact that NK cells are part of the malignant clone and therefore might have a decreased function. An alternative hypothesis could be that these patients may display a NK cell Receptor (NKR) genotype incapable of destroying leukemic cells with aberrant expression of HLA class I molecules. The polymorphic nature of the NKR genes generates diverse repertoires in the human population, which display specificity in the innate immune response. Materials and Methods: In the present study, 11 Killer cell Immunoglobulin-like Receptor (KIRs) and 2 CD94/NKG2 receptors were genotyped by PCR-SSP in 96 leukemic patients and 148 healthy Caucasians. Results and Conclusion: We report a significant increased frequency of the more inhibitory AB KIR phenotype in leukemic patients compared to the controls (31.1% in healthy controls vs. 51.0% in leukemic patients, Pc = 0.002), which is related to the high prevalence of the inhibitory KIR2DL2 in this population (Pc = 0.007). Moreover, two specific KIR phenotypes AB1 and AB9, including all inhibitory KIRs, were significantly associated with leukemic patients. Our study suggests that an important percentage of leukemic patients express a KIR phenotype in favor of escape from NK cell immunity.

Background: Nonmyeloablative conditioning regimens are more and more widely used in the setting of stem cell transplant due to a reduced transplant related mortality. However, these conditioning regimens include more immunosuppressive agents and little data in terms of immunological recovery are found in the literature. Population: 24 patients (pts) admitted for nonmyeloablative transplant from HLA identical donors were prospectively followed during a period of 1 year. All pts received a conditioning regimen consisting of rabbit ATG (fresenius), Fludarabine phosphate, Cyclophosphamide ( ARA-C for myeloid malignancies) cyclosporin A and mycophenolate mofetil (MMF). Lymphocytes markers expression as well as lymphocytes absolute numbers were studied to evaluate the cellular immunologic recovery. IgG, IgA and IgM levels were also monitored during one year. Pts were stratified according to the presence of GVHD(acute and chronic) or not. Results: 24 pts with a median age of 52 (20–64) years old transplanted with an attenuated conditioning regimen, were evaluated. Median delay to recover 500 ANC and 20000 plt/ul was 8 days. Without GVHD, the pts recover a normal level of CD3, CD8, CD19,CD56 and CD45RO positive lymphocytes within 6 months. CD4+ and CD45RA + lymphocytes did not reach normal values within 1 year; Therefore the CD4/CD8 ratio remains low for more than 12 months. This observation explains the high incidence of oppotunistic infections in these pts even 6 months after transplantion. In our small seies,with or without GVHD neither IgA, nor IgM recovered within 1 year. IgG recovery is not evaluable because of human IVIG administration monthly after transplant. Conclusion: our small series confirms the rapid hematologic recovery after nonmyeloablative transplant.Cellular immunological recovery without GVHD is achieved within 6 months for most of the lymphocytes subsets excepted the CD4+ lymphocytes who need more than 12 months to recover. IgM and IgA recovery is also very slow.

Background:Nonmyeloablative conditioning regimens are more and more widely used in the setting of stem cell transplant due to a reduced transplant related mortality. However, these conditioning regimens include more immunosuppressive agents and little data in terms of immunological recovery are found in the literature.