Dendritic cell vaccination as postremission treatment to prevent or delay relapse in acute myeloid leukemia.

Relapse is a major problem in acute myeloid leukemia (AML) and adversely affects survival. In this phase 2 study, we investigated the effect of vaccination with dendritic cells (DCs) electroporated with Wilms' tumor 1 (WT1) messenger RNA (mRNA) as postremission treatment in 30 patients with AML at very high risk of relapse. There was a demonstrable antileukemic response in 13 patients. Nine patients achieved molecular remission as demonstrated by normalization of WT1 transcript levels, 5 of which were sustained after a median follow-up of 109.4 months. Disease stabilization was achieved in 4 other patients. Five-year overall survival (OS) was higher in responders than in nonresponders (53.8% vs 25.0%; P = .01). In patients receiving DCs in first complete remission (CR1), there was a vaccine-induced relapse reduction rate of 25%, and 5-year relapse-free survival was higher in responders than in nonresponders (50% vs 7.7%; P < .0001). In patients age ≤65 and >65 years who received DCs in CR1, 5-year OS was 69.2% and 30.8% respectively, as compared with 51.7% and 18% in the Swedish Acute Leukemia Registry. Long-term clinical response was correlated with increased circulating frequencies of polyepitope WT1-specific CD8+ T cells. Long-term OS was correlated with interferon-γ+ and tumor necrosis factor-α+ WT1-specific responses in delayed-type hypersensitivity-infiltrating CD8+ T lymphocytes. In conclusion, vaccination of patients with AML with WT1 mRNA-electroporated DCs can be an effective strategy to prevent or delay relapse after standard chemotherapy, translating into improved OS rates, which are correlated with the induction of WT1-specific CD8+ T-cell response. This trial was registered at www.clinicaltrials.gov as #NCT00965224.

Detection of a case of chronic myeloid leukaemia with deletions at the t(9;22) translocation breakpoints by a genome-wide non-invasive prenatal test.

OBJECTIVE: Non-invasive prenatal tests (NIPTs) interrogating the complete genome are able to detect not only fetal trisomy 13, 18 or 21 but additionally provide information on other (sub)chromosomal aberrations that can be fetal or maternal in origin. We demonstrate that in a subset of cases, this information is clinically relevant and should be reported to ensure adequate follow-up. METHOD: Genome-wide NIPT was carried out and followed by a software analysis pipeline optimized to detect subchromosomal aberrations. RESULTS: The NIPT profile showed deletions on chromosomes 9 and 22: NIPT 9q33.3q34.12(129150001-133750000)x1,22q11.23(23550001-25450000)x1,22q13.1(37850001-39600000)x1. This result was confirmed by single nucleotide polymorphism array on maternal genomic DNA, which also demonstrated that the deletions were somatic in nature. Fluorescence in situ hybridization and quantitative real-time polymerase chain reaction revealed that the deletions were flanking the translocation breakpoint on the derivative chromosome 9 as the result of a t(9;22)(q34;q11.2) translocation with BCR-ABL1 fusion typical for chronic myeloid leukaemia (CML). Multidisciplinary counselling, together with complete blood count, taught that the woman was in an early chronic phase CML. The woman was followed up closely, and treatment could be postponed until after delivery. CONCLUSION: Genome-wide NIPT identified a CML in chronic phase caused by the typical t(9;22)(q34;q11.2) translocation and accompanied by deletions flanking the translocation breakpoints. © 2016 John Wiley & Sons, Ltd.

Routine serum creatinine measurements: how well do we perform?

BACKGROUND: The first aim of the study was to investigate the accuracy and intra-laboratory variation of serum creatinine measurements in clinical laboratories in Flanders. The second purpose was to check the effect of this variation in serum creatinine concentration results on the calculated estimated glomerular filtration rate (eGFR) and the impact on classification of patients into a chronic kidney disease (CKD) stage. METHODS: 26 routine instruments were included, representing 13 different types of analyzers from 6 manufacturers and covering all current methodologies (Jaffe, compensated Jaffe, enzymatic liquid and dry chemistry methods). Target values of five serum pools (creatinine concentrations ranging from 35 to 934 µmol/L) were assigned by the gold standard method (ID-GC/MS). RESULTS: Intra-run CV (%) (n = 5) and bias (%) from the target values were higher for low creatinine concentrations. Especially Jaffe and enzymatic dry chemistry methods showed a higher error. The calculated eGFR values corresponding with the reported creatinine concentration ranges resulted in a different CKD classification in 47% of cases. CONCLUSIONS: Although most creatinine assays claim to be traceable to the gold standard (ID-GC/MS), large inter-assay differences still exist. The inaccuracy in the lower concentration range is of particular concern and may lead to clinical misinterpretation when the creatinine-based eGFR of the patient is used for CKD staging. Further research to improve harmonization between methods is required.

Absence of BCL-2 Expression Identifies a Subgroup of AML with Distinct Phenotypic, Molecular, and Clinical Characteristics.

Acute myeloid leukemia (AML) is a hematologic malignancy characterized by the rapid and uncontrolled clonal growth of myeloid lineage cells in the bone marrow. The advent of oral, selective inhibitors of the B-cell leukemia/lymphoma-2 (BCL-2) apoptosis pathway, such as venetoclax, will likely induce a paradigm shift in the treatment of AML. However, the high cost of this treatment and the risk of additive toxicity when used in combination with standard chemotherapy represent limitations to its use and underscore the need to identify which patients are most-and least-likely to benefit from incorporation of venetoclax into the treatment regimen. Bone marrow specimens from 93 newly diagnosed AML patients were collected in this study and evaluated for BCL-2 protein expression by immunohistochemistry. Using this low-cost, easily, and readily applicable analysis method, we found that 1 in 5 AML patients can be considered as BCL-2-. In addition to a lower bone marrow blast percentage, this group exhibited a favorable molecular profile characterized by lower WT1 expression and underrepresentation of FLT3 mutations. As compared to their BCL-2+ counterparts, the absence of BCL-2 expression was associated with a favorable response to standard chemotherapy and overall survival, thus potentially precluding the necessity for venetoclax add-on.

A novel haemocytometric COVID-19 prognostic score developed and validated in an observational multicentre European hospital-based study.

COVID-19 induces haemocytometric changes. Complete blood count changes, including new cell activation parameters, from 982 confirmed COVID-19 adult patients from 11 European hospitals were retrospectively analysed for distinctive patterns based on age, gender, clinical severity, symptom duration, and hospital days. The observed haemocytometric patterns formed the basis to develop a multi-haemocytometric-parameter prognostic score to predict, during the first three days after presentation, which patients will recover without ventilation or deteriorate within a two-week timeframe, needing intensive care or with fatal outcome. The prognostic score, with ROC curve AUC at baseline of 0.753 (95% CI 0.723-0.781) increasing to 0.875 (95% CI 0.806-0.926) on day 3, was superior to any individual parameter at distinguishing between clinical severity. Findings were confirmed in a validation cohort. Aim is that the score and haemocytometry results are simultaneously provided by analyser software, enabling wide applicability of the score as haemocytometry is commonly requested in COVID-19 patients.

Carboxypeptidase M expressed by human bone marrow cells cleaves the C-terminal lysine of stromal cell-derived factor-1alpha: another player in hematopoietic stem/progenitor cell mobilization?

Carboxypeptidase M (CPM) is a membrane-bound zinc-dependent protease that cleaves C-terminal basic residues, such as arginine or lysine, from peptides/proteins. We examined whether CPM is expressed by hematopoietic and stromal cells and could degrade stromal cell-derived factor (SDF)-1alpha, a potent chemoattractant for hematopoietic stem/progenitor cells (HSPC). We found that (a) CPM transcript is expressed by bone marrow (BM) and mobilized peripheral blood CD34(+) cells, myeloid, erythroid, and megakaryocytic cell progenitors, mononuclear cells (MNC), polymorphonuclear cells (PMN), and stromal cells, including mesenchymal stem cells; and that (b) granulocyte-colony-stimulating factor (G-CSF) significantly increases its expression at the gene and protein levels in MNC and PMN. Moreover, we found that recombinant CPM cleaves full-length SDF-1alpha (1-68) rapidly, removing the C-terminal lysine and yielding des-lys SDF-1alpha (1-67). We demonstrated that such CPM treatment of SDF-1alpha reduced the in vitro chemotaxis of HSPC, which, however, was preserved when the CPM was exposed to the carboxypeptidase inhibitor dl-2-mercaptomethyl-3-guanidino-ethylthiopropanoic acid. Thus, we present evidence that CPM is expressed by cells occurring in the BM microenvironment and that the mobilizing agent G-CSF strongly upregulates it in MNC and PMN. We suggest that cleavage of the C-terminal lysine residue of SDF-1alpha by CPM leads to attenuated chemotactic responses and could facilitate G-CSF-induced mobilization of HSPC from BM to peripheral blood.

The role of the S1 binding site of carboxypeptidase M in substrate specificity and turn-over.

The influence of the P1 amino acid on the substrate selectivity, the catalytic parameters K(m) and k(cat), of carboxypeptidase M (CPM) (E.C. 3.4.17.12) was systematically studied using a series of benzoyl-Xaa-Arg substrates. CPM had the highest catalytic efficiency (k(cat)/K(m)) for substrates with Met, Ala and aromatic amino acids in the penultimate position and the lowest with amino acids with branched side-chains. Substrates with Pro in P1 were not cleaved in similar conditions. The P1 substrate preference of CPM differed from that of two other members of the carboxypeptidase family, CPN (CPN/CPE subfamily) and CPB (CPA/CPB subfamily). Aromatic P1 residues discriminated most between CPM and CPN. The type of P2 residue also influenced the k(cat) and K(m) of CPM. Extending the substrate up to P7 had little effect on the catalytic parameters. The substrates were modelled in the active site of CPM. The results indicate that P1-S1 interactions play a role in substrate binding and turn-over.

Novel LC-MS/MS method for plasma vancomycin: comparison with immunoassays and clinical impact.

BACKGROUND: Accurate quantification of vancomycin in plasma is important for adequate dose-adjustment. As literature suggests between-method differences, our first objective was to develop a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for total vancomycin in human plasma and to compare frequently used immunoassays with this method. Secondly, we investigated the clinical impact of between-method quantification differences. METHODS: For LC-MS/MS, lithium heparin plasma was extracted by adding a precipitation reagent containing the internal standard (vancomycin-des-leucine). Analysis was performed on an Acquity TQD mass spectrometer equipped with an Acquity UPLC 2795 separations module. Our method was analytically validated and compared with four frequently used immunoassays from four different manufacturers. Vancomycin concentrations were clinically classified as toxic, therapeutic and sub-therapeutic. Clinical discordance was calculated using LC-MS/MS as a reference. RESULTS: A novel LC-MS/MS method using protein precipitation as sole pretreatment and an analysis time of 5.0 min was developed. The assay had a total imprecision of 2.6-8.5%, a limit of quantification of 0.3 mg/L and an accuracy ranging from 101.4 to 111.2%. Using LC-MS/MS as reference, three immunoassays showed a mean proportional difference within 10% and one showed a substantial mean proportional difference of >20%. Clinical discordant interpretation of the obtained concentrations ranged from 6.1 to 22.2%. CONCLUSIONS: We developed a novel LC-MS/MS method for rapid analysis of total vancomycin concentrations in human plasma. Correlation of the method with immunoassays showed a mean proportional difference >20% for one of the assays, causing discordant clinical interpretation in more than 1 out of 5 samples.

Carboxypeptidase M in apoptosis, adipogenesis and cancer.

This review covers carboxypeptidase M (CPM) research that appeared in the literature since 2009. The focus is on aspects that are new or interesting from a clinical perspective. Available research tools are discussed as well as their pitfalls and limitations. Evidence is provided to suggest the potential involvement of CPM in apoptosis, adipogenesis and cancer. This evidence derives from the expression pattern of CPM and its putative substrates in cells and tissues. In recent years CPM emerged as a potential cancer biomarker, in well differentiated liposarcoma where the CPM gene is co-amplified with the oncogene MDM2; and in lung adenocarcinoma where coexpression with EGFR correlates with poor prognosis. The available data call for extended investigation of the function of CPM in tumor cells, tumor-associated macrophages, stromal cells and tumor neovascularisation. Such experiments could be instrumental to validate CPM as a therapeutic target.

C-terminal clipping of chemokine CCL1/I-309 enhances CCR8-mediated intracellular calcium release and anti-apoptotic activity.

Carboxypeptidase M (CPM) targets the basic amino acids arginine and lysine present at the C-terminus of peptides or proteins. CPM is thought to be involved in inflammatory processes. This is corroborated by CPM-mediated trimming and modulation of inflammatory factors, and expression of the protease in inflammatory environments. Since the function of CPM in and beyond inflammation remains mainly undefined, the identification of natural substrates can aid in discovering the (patho)physiological role of CPM. CCL1/I-309, with its three C-terminal basic amino acids, forms a potential natural substrate for CPM. CCL1 plays a role not only in inflammation but also in apoptosis, angiogenesis and tumor biology. Enzymatic processing differently impacts the biological activity of chemokines thereby contributing to the complex regulation of the chemokine system. The aim of the present study was to investigate whether (i) CCL1/I-309 is prone to trimming by CPM, and (ii) the biological activity of CCL1 is altered after C-terminal proteolytic processing. CCL1 was identified as a novel substrate for CPM in vitro using mass spectrometry. C-terminal clipping of CCL1 augmented intracellular calcium release mediated by CCR8 but reduced the binding of CCL1 to CCR8. In line with the higher intracellular calcium release, a pronounced increase of the anti-apoptotic activity of CCL1 was observed in the BW5147 cellular model. CCR8 signaling, CCR8 binding and anti-apoptotic activity were unaffected when CPM was exposed to the carboxypeptidase inhibitor DL-2-mercaptomethyl-3-guanidino-ethylthiopropanoic acid. The results of this study suggest that CPM is a likely candidate for the regulation of biological processes relying on the CCL1-CCR8 system.

Carboxypeptidase M: Multiple alliances and unknown partners.

Carboxypeptidase M (EC 3.4.17.12) belongs to the family of the carboxypeptidases. These enzymes remove C-terminal amino acids from peptides and proteins and exert roles in the physiological processes of blood coagulation/fibrinolysis, inflammation, food digestion and pro-hormone and neuropeptide processing. Among the carboxypeptidases CPM is of particular importance because of its constitutive expression in an active form at the surface of specialized cells and tissues in the human body. Despite the fact that the function(s) of this enzyme is not fully understood several suggestions have been made since its discovery more than two decades ago. Based on potential substrates and its presence, often on the boundary between the host and environment, a role in inflammation was proposed. This review describes how recent discoveries affected the insights in the cellular and physiological functions of CPM. A critical analysis of the potential endogenous peptide and protein substrates is provided. The distribution of CPM on different cell types and tissues and its expression in states of disease are discussed. There is evidence that CPM functions not only as a protease but also as a binding partner in cell-surface protein-protein interactions.

Ethanol dependence of alpha 1-antitrypsin C-terminal Lys truncation mediated by basic carboxypeptidases.

BACKGROUND: Patients with hereditary emphysema are treated with alpha 1-antitrypsin (alpha 1-proteinase inhibitor [A1PI]) concentrates. High-resolution isoelectric focusing (IEF) analysis of A1PI shows that commercial A1PI products have different glycoisoform band patterns predominantly caused by varying degrees of C-terminal Lys truncation at position 394 from the A1PI molecule. Basic carboxypeptidases (CPs) are a group of enzymes that specifically cleave C-terminal basic amino acids (Arg or Lys) from peptides and proteins. STUDY DESIGN AND METHODS: In this study, whether A1PI is a substrate for basic CPs was investigated. CPN and CPU, two CPs present in plasma, and CPM, a GPI-anchored membrane protein highly expressed in lung tissues, were included. RESULTS: Basic CPs are able to mediate the C-terminal Lys truncation of A1PI although with a very low efficiency. However, presence of ethanol, for example, during Cohn fractionation, renders A1PI highly susceptible to cleavage by CP with the extent of Lys truncation depending on the ethanol concentration. This ethanol concentration dependence elegantly explains the varying amounts of des-Lys A1PI present in commercial preparations purified from different Cohn fractions. CONCLUSIONS: The cause of C-terminal truncation of A1PI present in products used for augmentation therapy has been identified, and it has been shown that A1PI becomes a substrate for CPs, specifically CPN, because of the presence of ethanol during Cohn fractionation.