A GP1BA Variant in a Czech Family with Monoallelic Bernard-Soulier Syndrome.

Bernard-Soulier syndrome (BSS) is a rare inherited disorder characterized by unusually large platelets, low platelet count, and prolonged bleeding time. BSS is usually inherited in an autosomal recessive (AR) mode of inheritance due to a deficiency of the GPIb-IX-V complex also known as the von Willebrand factor (VWF) receptor. We investigated a family with macrothrombocytopenia, a mild bleeding tendency, slightly lowered platelet aggregation tests, and suspected autosomal dominant (AD) inheritance. We have detected a heterozygous GP1BA likely pathogenic variant, causing monoallelic BSS. A germline GP1BA gene variant (NM_000173:c.98G > A:p.C33Y), segregating with the macrothrombocytopenia, was detected by whole-exome sequencing. In silico analysis of the protein structure of the novel GPIbα variant revealed a potential structural defect, which could impact proper protein folding and subsequent binding to VWF. Flow cytometry, immunoblot, and electron microscopy demonstrated further differences between p.C33Y GP1BA carriers and healthy controls. Here, we provide a detailed insight into its clinical presentation and phenotype. Moreover, the here described case first presents an mBSS patient with two previous ischemic strokes.

Rituximab maintenance overcomes the negative prognostic factor of obesity in CLL: Subgroup analysis of the international randomized AGMT CLL-8a mabtenance trial.

No data are available regarding obesity and outcome in Chronic Lymphocytic Leukemia (CLL). We analyzed 263 patients from the AGMT CLL-8a Mabtenance trial for the impact of obesity. The trial included patients after rituximab-containing induction treatment in first or second line that had achieved at least a PR. A randomization to rituximab maintenance treatment (375 mg/m2 q3 months for 2 years) vs observation was performed. In this cohort 22% of the patients (58/263) were classified as obese. The baseline response to induction treatment was inferior in obese patients with a lower CR rate (43.1% vs 60.5% in obese vs non-obese, P = 0.018) and with a lower rate of patients achieving MRD negativity after chemoimmunotherapy induction treatment (19.6% vs 35.8%, P = 0.02). The PFS outcome of obese patients was significantly worse in the observation group of the trial (24 vs 39 months median PFS, P = 0.03). However, in the rituximab maintenance group the outcome for obese vs non-obese was not different (P = 0.4). In summary, obesity was overall associated with a worse outcome of chemoimmunotherapy induction. However, rituximab maintenance treatment seems to be able to overcome this negative effect.

A novel germline mutation in GP1BA gene N-terminal domain in monoallelic Bernard-Soulier syndrome.

Mutations in the GP1BA gene have been associated with platelet-type von Willebrand disease and Bernard-Soulier syndrome. Here, we report a novel GP1BA mutation in a family with autosomal dominant macrothrombocytopenia and mild bleeding. We performed analyses of seven family members. Using whole-exome sequencing of germline DNA samples, we identified a heterozygous single-nucleotide change in GP1BA (exone2:c.176T>G), encoding a p.Leu59Arg substitution in the N-terminal domain, segregating with macrothrombocytopenia. This variant has not been previously reported. We also analysed the structure of the detected sequence variant in silico. In particular, we used the crystal structure of the human platelet receptor GP Ibα N-terminal domain. Replacement of aliphatic amino-acid Leu 59 with charged, polar and larger arginine probably disrupts the protein structure. An autosomal dominant mode of inheritance, a family history of mild bleeding episodes, aggregation pattern in affected individuals together with evidence of mutation occurring in part of the GP1BA gene encoding the leucine-rich repeat region suggest a novel variant causing monoallelic Bernard-Soulier syndrome.

Comparison of Real-time Quantitative Polymerase Chain Reaction and Eight-color Flow Cytometry in Assessment of Minimal Residual Disease in Adult Acute Lymphoblastic Leukemia.

BACKGROUND: Minimal residual disease (MRD) is an important prognostic maker in acute lymphoblastic leukemia (ALL). However, few data comparing the measurement of adult ALL MRD using different methods in daily practice are available. We conducted an analysis comparing the importance of flow cytometry (FCM) and real-time quantitative polymerase chain reaction (PCR) in the assessment of MRD in adult ALL. PATIENTS AND METHODS: Fifty-six consecutive adult patients with both Philadelphia-negative and -positive ALL treated according to an intensive protocol were enrolled in the study. Bone marrow samples were acquired on day 26 and during week 11 of treatment. MRD evaluation was performed using 8-color FCM and PCR of immunoglobulin or T-cell receptor gene clonal rearrangements and BCR-ABL1, KMT2A-AF4 and E2A-PBX1 fusion genes. RESULTS: On day 26, both FCM and PCR seemed to have good discrimination sensitivity for overall survival (P = .001 to .008) and progression-free survival (P = .03 to .04) prediction for both Philadelphia-positive and -negative cases. The most sensitive method in week 11 was PCR including all results > 0 considered to indicate MRD positivity (P = .002 for overall survival and P = .02 for progression-free survival). PCR with other cutoffs was not sufficiently sensitive in week 11. Moreover, no FCM+ samples were found in week 11. The subanalysis of the Philadelphia-negative patients showed similar results. CONCLUSION: Our analysis showed that both FCM and PCR MRD assessment methods are sensitive for survival prediction during induction. However, we believe FCM could not be sufficiently sensitive in later phases of treatment.

Reproducible diagnosis of chronic lymphocytic leukemia by flow cytometry: An European Research Initiative on CLL (ERIC) & European Society for Clinical Cell Analysis (ESCCA) Harmonisation project.

The diagnostic criteria for CLL rely on morphology and immunophenotype. Current approaches have limitations affecting reproducibility and there is no consensus on the role of new markers. The aim of this project was to identify reproducible criteria and consensus on markers recommended for the diagnosis of CLL. ERIC/ESCCA members classified 14 of 35 potential markers as "required" or "recommended" for CLL diagnosis, consensus being defined as >75% and >50% agreement, respectively. An approach to validate "required" markers using normal peripheral blood was developed. Responses were received from 150 participants with a diagnostic workload >20 CLL cases per week in 23/150 (15%), 5-20 in 82/150 (55%), and <5 cases per week in 45/150 (30%). The consensus for "required" diagnostic markers included: CD19, CD5, CD20, CD23, Kappa, and Lambda. "Recommended" markers potentially useful for differential diagnosis were: CD43, CD79b, CD81, CD200, CD10, and ROR1. Reproducible criteria for component reagents were assessed retrospectively in 14,643 cases from 13 different centers and showed >97% concordance with current approaches. A pilot study to validate staining quality was completed in 11 centers. Markers considered as "required" for the diagnosis of CLL by the participants in this study (CD19, CD5, CD20, CD23, Kappa, and Lambda) are consistent with current diagnostic criteria and practice. Importantly, a reproducible approach to validate and apply these markers in individual laboratories has been identified. Finally, a consensus "recommended" panel of markers to refine diagnosis in borderline cases (CD43, CD79b, CD81, CD200, CD10, and ROR1) has been defined and will be prospectively evaluated. © 2017 International Clinical Cytometry Society.

Rituximab maintenance versus observation alone in patients with chronic lymphocytic leukaemia who respond to first-line or second-line rituximab-containing chemoimmunotherapy: final results of the AGMT CLL-8a Mabtenance randomised trial.

BACKGROUND: In many patients with chronic lymphocytic leukaemia requiring treatment, induction therapy with rituximab plus chemotherapy improves outcomes compared with chemotherapy alone. In this study we aimed to investigate the potential of rituximab maintenance therapy to prolong disease control in patients who respond to rituximab-containing induction regimens. METHODS: In this randomised, international, multicentre, open-label, phase 3 clinical trial, we enrolled patients who had achieved a complete response (CR), CR with incomplete bone marrow recovery (CRi), or partial response (PR) to first-line or second-line rituximab-containing chemoimmunotherapy and randomly assigned them in a 1:1 ratio (central block randomisation in the electronic case report form system) to either intravenous rituximab 375 mg/m(2) every 3 months, or observation alone, for 2 years. Stratification was by country, line of treatment, type of chemotherapy added to the rituximab backbone, and degree of remission following induction. The primary endpoint was progression-free survival. Efficacy analysis was done in the intention-to-treat population. This is the final, event-triggered analysis. Final analysis was triggered by the occurrence of 92 events. This trial is registered with ClinicalTrials.gov, number NCT01118234. FINDINGS: Between April 1, 2010, and Dec 23, 2013, 134 patients were randomised to rituximab and 129 to observation alone. Median observation times were 33·4 months (IQR 25·7-42·8) for the rituximab group and 34·0 months (25·4-41·9) for the observation group. Progression-free survival was significantly longer in the rituximab maintenance group (47·0 months, IQR 28·5-incalculable) than with observation alone (35·5 months, 95% CI 25·7-46·3; hazard ratio [HR] 0·50, 95% CI 0·33-0·75, p=0·00077). The incidence of grade 3-4 haematological toxicities other than neutropenia was similar in the two treatment groups. Grade 3-4 neutropenia occurred in 28 (21%) patients in the rituximab group and 14 (11%) patients in the observation group. Apart from neutropenia, the most common grade 3-4 adverse events were upper (five vs one [1%] patient in the observation group) and lower (three [2%] vs one [1%]) respiratory tract infection, pneumonia (nine [7%] vs two [2%]), thrombopenia (four [3%] vs four [3%]), neoplasms (five [4%] vs four [3%]), and eye disorders (four [3%] vs two [2%]). The overall incidence of infections of all grades was higher among rituximab recipients (88 [66%] vs 65 [50%]). INTERPRETATION: Rituximab maintenance therapy prolongs progression-free survival in patients achieving at least a PR to induction with rituximab plus chemotherapy, and the treatment is well tolerated overall. Although it is associated with an increase in infections, there is no excess in infection mortality, suggesting that remission maintenance with rituximab is an effective and safe option in the management of chronic lymphocytic leukaemia in early treatment phases. FUNDING: Arbeitsgemeinschaft Medikamentöse Tumortherapie gemeinnützige GmbH (AGMT), Roche.

Autocrine Signaling by Wnt-5a Deregulates Chemotaxis of Leukemic Cells and Predicts Clinical Outcome in Chronic Lymphocytic Leukemia.

PURPOSE: ROR1, a receptor in the noncanonical Wnt/planar cell polarity (PCP) pathway, is upregulated in malignant B cells of chronic lymphocytic leukemia (CLL) patients. It has been shown that the Wnt/PCP pathway drives pathogenesis of CLL, but which factors activate the ROR1 and PCP pathway in CLL cells remains unclear. EXPERIMENTAL DESIGN: B lymphocytes from the peripheral blood of CLL patients were negatively separated using RosetteSep (StemCell) and gradient density centrifugation. Relative expression of WNT5A, WNT5B, and ROR1 was assessed by quantitative real-time PCR. Protein levels, protein interaction, and downstream signaling were analyzed by immunoprecipitation and Western blotting. Migration capacity of primary CLL cells was analyzed by the Transwell migration assay. RESULTS: By analyzing the expression in 137 previously untreated CLL patients, we demonstrate that WNT5A and WNT5B genes show dramatically (five orders of magnitude) varying expression in CLL cells. High WNT5A and WNT5B expression strongly associates with unmutated IGHV and shortened time to first treatment. In addition, WNT5A levels associate, independent of IGHV status, with the clinically worst CLL subgroups characterized by dysfunctional p53 and mutated SF3B1. We provide functional evidence that WNT5A-positive primary CLL cells have increased motility and attenuated chemotaxis toward CXCL12 and CCL19 that can be overcome by inhibitors of Wnt/PCP signaling. CONCLUSIONS: These observations identify Wnt-5a as the crucial regulator of ROR1 activity in CLL and suggest that the autocrine Wnt-5a signaling pathway allows CLL cells to overcome natural microenvironmental regulation.

Ofatumumab added to dexamethasone in patients with relapsed or refractory chronic lymphocytic leukemia: Results from a phase II study.

The treatment of relapsed/refractory chronic lymphocytic leukemia (CLL) remains a challenging clinical issue. An important treatment option is the use of high-dose corticosteroids. The purpose of this clinical trial was to determine the efficacy and toxicity of an ofatumumab-dexamethasone (O-Dex) combination in relapsed or refractory CLL. The trial was an open-label, multicenter, nonrandomized, Phase II study. The O-Dex regimen consisted of intravenous ofatumumab (Cycle 1: 300 mg on day 1, 2,000 mg on days 8, 15, and 22; Cycles 2-6: 1,000 mg on days 1, 8, 15, and 22) and oral dexamethasone (40 mg on days 1-4 and 15-18; Cycles 1-6). The O-Dex regimen was given until best response, or a maximum of six cycles. Thirty-three patients (pts) were recruited. Twenty-four (73%) pts completed at least three cycles of therapy. The remaining nine pts were prematurely discontinued owing to Grade 3/4 infections (seven pts), disease progression (one pt), or uncontrollable diabetes mellitus (one pt). Overall response rates/complete remissions (ORR/CR) were achieved in 22/5 pts (67/15%). The median progression-free survival (PFS) was 10 months. In pts with p53 defects (n = 8), ORR/CR were achieved in 5/2 pts (63/25%) with a median PFS of 10.5 months. The median overall survival (OS) was 34 months. The Grades 3-5 infectious toxicity in 33% of pts represented the most frequent side effect during the treatment period. In conclusion, the O-Dex regimen shows a relatively high ORR and CR with promising findings for PFS and OS. The study was registered at www.clinicaltrials.gov (NCT01310101).

Detection of minimal residual disease in mantle cell lymphoma-establishment of novel eight-color flow cytometry approach.

BACKGROUND: Minimal residual disease (MRD) detection is an essential tool for therapy response assessment in a considerable number of hematooncologic disorders, including mantle cell lymphoma (MCL). Flow cytometry (FCM) ranks among the most effective approaches, which allows rapid sample processing and compete successfully with highly sensitive molecular methods like polymerase chain reaction. Because FCM is ordinarily applied to detect MRD in B-lineage diseases like chronic lymphocytic leukemia, a similar method could be used in MCL. We decided to test our novel eight-color FCM approach in MCL MRD detection. METHODS: Using an eight-color FCM protocol designed by us, the expression of 24 selected surface antigens in a cohort of 30 patients with newly diagnosed leukemic MCL and 20 normal controls were compared to establish markers that can reliably distinguish normal B-lymphocytes from the MCL population. The sensitivity of the designed protocol was tested using serial dilution studies. RESULTS: Although MCL presents high immunophenotypic variability, the combination of CD20/23/5/19/200/62L/3/45 seems to be very favorable in flow cytometric MRD measurement. CONCLUSIONS: Our eight-color FCM protocol could easily detect MRD in MCL patients, and reaches a sensitivity of up to 2 × 10(-4) .

Detection of Minimal Residual Disease in Mantle Cell Lymphoma. Establishment of Novel 8-Color Flow Cytometry Approach.

Backround: Minimal residual disease (MRD) detection is an essential tool for therapy response assessment in a considerable number of hematooncologic disorders including mantle cell lymphoma (MCL). Flow cytometry (FCM) ranks among the most effective approaches which allow rapid sample processing and compete successfully with highly sensitive molecular methods like polymerase chain reaction (PCR). Since FCM is ordinarily applied to detect MRD in B-lineage diseases like chronic lymphocytic leukemia (CLL), a similar method could be used in MCL. We decided to test our novel 8-color FCM approach in MCL MRD detection. Methods: Employing an 8-color FCM protocol designed by us, the expression of 24 selected surface antigens in a cohort of 30 patients with newly diagnosed leukemic MCL and 20 normal controls were compared to one another to establish markers that can reliably distinguish normal B lymphocytes from the MCL population. The sensitivity of the designed protocol was tested using serial dilution studies. Results: Although MCL presents high immunophenotypic variability the combination of CD20/23/5/19/200/62L/3/45 appears to be very favorable in flow cytometric MRD measurement. Conclusions: Our 8-color FCM protocol could easily detect MRD in MCL patients and reaches a sensitivity of up to 2×10-4 . This article is protected by copyright. All rights reserved.

Residual cancer lymphocytes in patients with chronic lymphocytic leukemia after therapy show increased expression of surface antigen CD52 detected using quantitative fluorescence cytometry.

BACKGROUND: Rituximab and alemtuzumab, mAbs used in recent years to treat CLL, are directed against antigens CD20 and CD52. CD20 is not highly expressed by CLL tumor cells, and rituximab does not have significant effectiveness in CLL unless combined with chemotherapy. Alemtuzumab targets CD52, which is much more highly expressed, and is currently the most effective agent used alone for CLL. Variability in expression of both antigens among these patients might be related to different individual therapeutic responses to mAb therapy. PATIENTS AND METHODS: A total 95 patients diagnosed with CLL and/or SLL were divided into 4 groups: (1) untreated; (2) in complete or partial remission; (3) disease in progression; and (4) diagnosed with SLL. Flow cytometry of peripheral blood cells included gating of the CD5(+)CD19(+) tumor population, within which mean fluorescence intensity of fluorescein isothiocyanate (FITC) conjugated with anti-CD20 or anti-CD52 antibody was measured. The resulting expression of the 2 antigens was deduced from the calibration curve using Quantum FITC particles. RESULTS: Expression of CD20 showed no significant differences among the 4 groups of patients. However, significantly greater expression of surface antigen CD52 was recorded in patient group 2 in complete or partial remission (P < .001). CONCLUSION: The residual population of CLL cells after therapy is characterized by increased surface detection of CD52. Although the exact cause of this phenomenon is unknown, our results provide a basis to consider the potential for CLL consolidation therapy using alemtuzumab.

Influence of pulsed electromagnetic and pulsed vector magnetic potential field on the growth of tumor cells.

AIMS AND BACKGROUND: Tumor diseases cause 20% of deaths in Europe and they are the second most common cause of death and morbidity after cardiovascular diseases. Thus, tumor cells are target of many therapeutic strategies and tumor research is focused on searching more efficient and specific drugs as well as new therapeutic approaches. One of the areas of tumor research is an issue of external fields. In our work, we tested influence of a pulsed electromagnetic field (PEMF) and a hypothetic field of the pulsed vector magnetic potential (PVMP) on the growth of tumor cells; and further the possible growth inhibition effect of the PVMP. METHODS: Both unipolar and bipolar PEMF fields of 5 mT and PVMP fields of 0 mT at frequencies of 15 Hz, 125 Hz and 625 Hz were tested on cancer cell lines derived from various types of tumors: CEM/C2 (acute lymphoblastic leukemia), SU-DHL-4 (B-cell lymphoma), COLO-320DM (colorectal adenocarcinoma), MDA-BM-468 (breast adenocarcinoma), and ZR-75-1 (ductal carcinoma). Cell morphology was observed, proliferation activity using WST assay was measured and simultaneous proportion of live, early apoptotic and dead cells was detected using flow cytometry. RESULTS: A PEMF of 125 Hz and 625 Hz for 24 h-48 h increased proliferation activity in the 2 types of cancer cell lines used, i.e. COLO-320DM and ZR-75-1. In contrast, any of employed methods did not confirm a significant inhibitory effect of hypothetic PVMP field on tumor cells.

Intra- and interlaboratory variability of paroxysmal nocturnal hemoglobinuria testing by flow cytometry following the 2012 Practical Guidelines for high-sensitivity paroxysmal nocturnal hemoglobinuria testing.

BACKGROUND: Sutherland et al. recently published the Practical Guidelines for high-sensitivity detection of paroxysmal nocturnal hemoglobinuria (PNH) clones by flow cytometry (FCM), containing concise protocols for PNH testing. METHODS: Using this approach, we studied the intra- and interlaboratory variability observed in a multicenter study in which fresh blood samples containing three clinically relevant PNH clone sizes within the granulocytic, monocytic, and red blood cell (RBC) populations were shipped to each participating center. RESULTS: Coefficients of variation (CVs) for precision/reproducibility analysis ranged from 0.01%/0.02% to 0.48%/0.45% (big clone), from 0.69%/1.52% to 4.24%/5.80% (small-intermediate clone), from 1.47%/3.91% to 15.01% /17.83% (minor clone) for PNH white blood cells (WBCs) and from 0.24%/0.48% to 1.76%/1.83% (big clone), from 0.80%/1.14% to 2.39%/4.45% (small-intermediate clone), from 1.09%/3.36% to 10.54%/10.23% (minor clone) for PNH RBCs, respectively. Linear regression analysis showed excellent performance correlation between centers (r > 0.99), Wilcoxon rank test revealed no statistically significant differences for PNH granulocytes, monocytes, and RBCs (P > 0.05%), Bland-Altman analysis demonstrated good performance agreement for all target PNH clones (mean bias ranging from -1.47 to 0.71). CONCLUSION: Our results demonstrate very good intra- and interlaboratory performance characteristics for both precision and reproducibility analyses and excellent correlation and agreement between centers for all target PNH clone sizes. Our data confirm the reliability and robustness of the recently published Practical Guidelines approach for high sensitivity PNH testing by flow cytometry and suggest that such an approach represents an excellent basis for standardization of PNH testing by flow cytometry.

Fludarabine with cytarabine followed by reduced-intensity conditioning and allogeneic hematopoietic stem cell transplantation in patients with poor-risk chronic lymphocytic leukemia.

Allogeneic stem cell transplantation (SCT) is a treatment option for patients with poor-risk chronic lymphocytic leukemia (CLL). Sequential use of chemotherapy and reduced-intensity conditioning has been proposed to improve the treatment outcomes. Fludarabine (30 mg/m(2)/day) and cytarabine (2 g/m(2)/day) for 4 days (combination of fludarabine with cytarabine; FAraC) were used for cytoreduction. After 3 days of rest, reduced intensity conditioning (RIC) was carried out consisting of 4 Gy total body irradiation, 10-20 mg/kg/day antithymocyte globulin for 3 days, and 40-60 mg/kg/day cyclophosphamide for 2 days. The median time of neutrophil engraftment was 16 days. The most frequent toxicities were grades III/IV infections in 12 of 15 cases and gastrointestinal toxicities in 8 of 15 cases. Remission (complete remission + partial remission) was achieved in 14 of 15 patients (93 %), minimal residual disease negativity according to flowcytometric analysis was observed in 10 patients. Nonrelapse mortality after 1 and 2 years was 7 and 13 %, respectively. After the median follow-up from SCT of 30 months, 80 % of patients were alive (12/15), three patients have died, and three relapses occurred. The FAraC-RIC protocol seems to be a promising approach to the treatment of poor-risk CLL with a high response rate of 93 % and favorable progression-free survival and overall survival of 70 and 85 % at 2 years after SCT, respectively. Other prospective clinical trials are needed to confirm the results of this novel therapeutic strategy.