There are two major isoforms of BCR::ABL1, the Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) specific p185BCR::ABL1, and the p210BCR::ABL1, which defines 95% of chronic myeloid leukemia (CML). These two isoforms differ in the presence of the oncogenic pleckstrin- and DBL-homology domains (DH and PH) in p210BCR::ABL1. The p210BCR::ABL1 induces genomic instability (GI) by double-strand breaks (DSB). The DNA damage and repair response (DDR) repairs DSBs. BCR::ABL1 compromises the fidelity of DDR by promoting the repair of DSB through single-strand annealing (SSA), a mutagenic pathway, and through non-homologous end joining (NHEJ). Both DDR mechanisms may not be sufficiently suppressed by tyrosine kinase inhibitors (TKI), resulting in imprecise repair and mutations. As a model, we used early passages of thirteen long-term cultures derived from patients (PD-LTCs) with acute lymphoblastic leukemia (ALL). Five PD-LTCs were from Ph+ ALLs with the associated p185BCR::ABL1, one of them with the T315I mutation. The two PD-LTCs from lymphoblastic CML blast crisis (CML l-BC) had the p210BCR::ABL1 fusion protein. The Ph-like PD-LTC exhibited an ETV6::ABL1 fusion protein. Two PD-LTCs harbored the t(1;19), which encoded the E2A::PBX1 fusion protein. The t(11;19) translocation encoding MLL::MLLT1 characterized one PD-LTC. We used the two PD-LTCs with no translocation and a complex karyotype as a reference. These cells represent the closest model to primary ALL cells as they are genomically and immunologically stable and did not undergo the classical crisis of a transformed cell line. They also enabled the determination of a relationship between GI and the response to TKI therapy in Ph+ ALL, as each of the Ph+ and Ph-like PD-LTCs has a different response to TKI. For the genome-wide measurement of the DSBs, we focused on INDUCE-seq, a technique we have recently developed. It allows for defining every single DSB at a molecular level, followed by bioinformatic analysis of DSBs. In this way, it is possible to define the absolute number of DSBs, their recurrency, and the number of DSBs per chromosome and their role in response to therapy and leukemogenesis. We aimed to determine the role of GI induced by rearranged ABL1 in the pathogenesis of Ph+ and Ph-like lymphoblastic leukemia and the response to TKI. We also wanted to compare the two major BCR::ABL1 isoforms, p185BCR::ABL1 and p210BCR::ABL1, regarding the induction of GI. We found that PD-LTCs from Ph+ ALL with their p185BCR::ABL1 induced a higher rate of GI by DSB than those from CML l-BC with their p210BCR::ABL1. We observed a higher absolute number of DSBs normalized to the amount of DNA extracted in p185BCR::ABL1-positive PD-LTCs (mean of ~89K) than in p210BCR::ABL1-positive PD-LTCs (mean of ~47K) and every other PD-LTC (mean of ~42K). ETV6::ABL1 induced a total number of DSB close to p185BCR::ABL1 (mean of ~ 75K) in the Ph-like PD-LTC. For both BCR::ABL1 isoforms and the Ph-like PD-LTC, the recurrency (the rate of DSBs in single genes) was higher than in other PD-LTCs, with a higher rate in p185BCR::ABL1-positive PD-LTCs than in those harboring p210BCR::ABL1. There was a relationship between sensitivity to TKI and the recurrency of DSB in the TKI-sensitive PD-LTCs. The lower the recurrency, the higher the sensitivity to TKI. The p185BCR::ABL1 fusion strongly induced DSBs in chromosomes 5 and 8. As no the induction of DSBs in chromosomes 5 and 8 was more likely related to the leukemogenesis of Ph+ ALL. Our still preliminary data demonstrate the significance of GI for the leukemogenesis and the response to TKI of lymphoblastic leukemia with the rearrangement of ABL1. It is not yet clear whether GI may be independent of ABL1 kinase activity, a target of TKI. It has to be confirmed by clinical studies.

The initial rate of reduction of BCR::ABL1 mRNA on TKI therapy, usually measured as the halving time over the first 3 months of treatment, has prognostic value for both early and late responses as well as the likelihood of achieving TFR. Standardized measurement of pretreatment disease levels by RT-qPCR, however, is problematic due to the different properties of the 3 established reference genes (ABL1, GUSB, BCR) used for CML MRD analysis. These differences are not relevant for standard MRD assessments, but the use of ABL1 or BCR results in reference gene-specific distortions at high disease burdens that limit their utility for assessment of baseline disease levels. GUSB is completely independent of BCR::ABL1 and is thus theoretically the best reference gene to determine halving times. To date, however, no comparative analysis of the utility of different reference genes to assess early response kinetics has been performed. We have evaluated the utility of halving times derived using GUSB and ABL1 as reference genes in FASCINATION, a multicenter, prospective, open-label, interventional phase II trial designed to evaluate the efficacy and tolerability of asciminib following <6 weeks treatment with other TKIs or <4 weeks of hydroxyurea. Halving times in days were calculated by comparing BCR::ABL1/ABL1 and BCR::ABL1/GUSB levels at trial entry (63% and 23%, respectively, at the start of asciminib) to the corresponding measurements at 3 months on asciminib. Halving times and IS levels at 3 months were compared to molecular outcomes at 18 months. Of 103 cases with available data, 45 achieved DMR at 18 months (MR4 or better; median 0.0015% IS) and 58 did not achieve DMR (median 0.052% IS). Median halving times were shorter for patients who achieved DMR using both ABL1 (13.5 vs 20.9, P<0.001) and GUSB (11.2 vs 18.1, P<0.001) as reference genes. Similarly, IS values at 3 months were significantly lower for cases who achieved DMR at 18 months (0.23% vs 1.6%; P<0.001). Using ROC analysis, the predictive value of GUSB halving times (AUC GUSB = 0.792) for achievement of DMR at 18 months was superior to both ABL1 halving times (AUC ABL1 = 0.746) and IS values at 3 months (AUC = 0.776). Similarly, we found that GUSB halving times correlated better (r=0.58, Spearman's rank correlation) with month 18 IS levels considered as a continuous variable compared to both ABL1 halving time (r=0.47) and month 3 IS levels (r=0.51). Focusing on GUSB, 19/51 (37%) cases had a halving time shorter than the median for all cases (13.9 days) but were not in DMR at 18 months. 12 of these 19 cases also had lower than the median IS levels at 3 months (0.73%). Conversely 13/52 cases (25%) had a long halving time but achieved DMR at 18 months. 8/13 also had higher than median IS levels at 3 months. Of the 45 cases who achieved DMR at 18 months, 11 (24%) had IS levels at 3 months that were higher (median = 3.97%, range 0.77%-35.3%) than the median for all cases (0.73%). Only 1/11 had a shorter than median GUSB halving time. Conversely, 17/58 (29%) of cases who were not in DMR at 18 months had <0.73% IS at 3 months (median = 0.40; range 0.05-0.70); only 5/17 had long GUSB halving times. These data indicate that combining halving times with 3 month IS data adds limited additional predictive value. Since GUSB measurements remain largely unstandardized, we assessed the performance of the AcroMetrix™ BCR-ABL Panel (Thermo Fisher), recently calibrated to GUSB and BCR as well as ABL1, to standardize MRD results using GUSB as a reference gene in two centers. Established GUSB conversion factors (CF) derived by sample exchange were essentially indistinguishable from those derived using the panel [Lab 1: existing CF (0.99) / panel CF (1.02) = 0.97; Lab 2: existing CF (1.57) / panel CF (1.40) = 1.12, thus validating the panel to standardize GUSB measurements. We conclude that halving times over the first 3 months of asciminib treatment using GUSB or ABL1 as well as IS levels at 3 months are all predictive of molecular response at 18 months, but the predictive value of GUSB halving times are greatest. We therefore recommend that standardized baseline BCR::ABL1/GUSB measurements are incorporated into future studies to enable comprehensive assessment of the value of BCR::ABL1 halving times for routine management.

Precise and reliable predictive parameters to accurately identify chronic myeloid leukemia (CML) patients who can successfully discontinue their tyrosine kinase inhibitor (TKI) treatment are lacking. One promising parameter is depth of molecular response measured by BCR::ABL1 digital PCR (dPCR). The aim of this study was to validate a previously described prediction cutoff of 0.0023%(IS) and to assess the value of dPCR for treatment-free remission (TFR) prediction in relation to other clinical parameters. A droplet-based dPCR assay assessed BCR::ABL1 %(IS) prior to TKI discontinuation. The primary endpoint was molecular recurrence (MolR) by 36 months. A total of 186 patients from Canada, Germany, and the Netherlands were included. In patients with a first TKI discontinuation attempt (n = 163), a BCR::ABL1 dPCR < and >= 0.0023%(IS) had a MolR probability of 33% and 70%, respectively. Patients treated less than 6 years with a BCR::ABL1 dPCR <0.0023%IS had a MolR probability of 31%. After correction for treatment duration, both high dPCR value and the use of imatinib (vs. second-generation TKI) were significantly associated with a higher risk of MolR (HR of 3.66, 95%CI 2.06-6.51, p < .001; and 2.85, 95%CI 1.25-6.46, p = .013, respectively). BCR::ABL1 dPCR was not associated with TFR outcome after second TKI discontinuation, however, with the limitation of a small number of patients analyzed (n = 23). In conclusion, BCR::ABL1 digital PCR based on the cutoff of 0.0023%(IS) is a valuable predictive tool to identify CML patients with a high probability of TFR success after first TKI discontinuation, including patients treated for less than 6 years.

Reverse transcriptases (RT) are essential tools in BCR::ABL1 fusion transcript monitoring in chronic myeloid leukemia (CML). The RT type and cDNA priming method may impair the stoichiometry of cDNA synthesis, thereby potentially introducing a bias in BCR::ABL1 qRT-PCR data. Using the Acrometrix™ BCR::ABL1 reference panel and 37 clinical specimens, we have comparatively investigated the performance of the RTs MLV and SuperScript IV with random hexamer vs. target-specific priming. Quantitative RT-PCR results identified the priming type and RT type as major factors for diagnostic data variation, mainly due to the different efficacies of processing BCR::ABL1 low-copy-numbers (<50) compared to GUSB or ABL1 high-copy targets. The impairment of SuperScript IV in processing low- and high-copy-number RNA targets equally was not reflected by the diagnostically relevant Log (BCR::ABL1/GUSB%) values. Therefore, the correct representation of housekeeping and BCR::ABL1 target genes should have priority when aiming at as high a number of housekeeping gene copies as possible. Our data suggest that for improving BCR::ABL1 assay sensitivity, increased RNA/cDNA amounts and the use of distinct RT/priming combinations are advantageous. However, for inter-laboratory harmonization, the proper conversion factor according to the CML international standard (IS) has to be reevaluated each time the grade of RT is changed.

Membrane transporters are important determinants of drug bioavailability. Their expression and activity affect the intracellular drug concentration in leukemic cells impacting response to therapy. Pharmacogenomics represents genetic markers that reflect allele arrangement of genes encoding drug transporters associated with treatment response. In previous work, we identified SNP rs460089 located in the promotor of SLC22A4 gene encoding imatinib transporter OCTN1 as influential on response of patients with chronic myeloid leukemia treated with imatinib. Patients with rs460089-GC pharmacogenotype had significantly superior response to first-line imatinib treatment compared to patients with rs460089-GG. This study investigated whether pharmacogenotypes of rs460089 are associated with sustainability of treatment-free remission (TFR) in patients from the EUROpean Stop Kinase Inhibitor (EURO-SKI) trial. In the learning sample, 176 patients showed a significantly higher 6-month probability of molecular relapse free survival (MRFS) in patients with GC genotype (73%, 95% CI: 60–82%) compared to patients with GG (51%, 95% CI: 41–61%). Also over time, patients with GC genotype had significantly higher MRFS probabilities compared with patients with GG (HR: 0.474, 95% CI: 0.280-0.802, p = 0.0054). Both results were validated with data on 93 patients from the Polish STOP imatinib study. In multiple regression models, in addition to the investigated genotype, duration of TKI therapy (EURO-SKI trial) and duration of deep molecular response (Polish study) were identified as independent prognostic factors. The SNP rs460089 was found as an independent predictor of TFR.

The achievement of major molecular response (MMR, BCR::ABL1 ≤ 0.1% IS) within the first year of treatment with tyrosine kinase inhibitors (TKI) is a milestone in the therapeutic management of patients with newly diagnosed chronic myeloid leukemia (CML). We analyzed the predictive value of gene expression levels of ESPL1/Separase, PTTG1/Securin and PTTG1IP/Securin interacting protein for MMR achievement within 12 months. Relative expression levels (normalized to GUSB) of ESPL1, PTTG1 and PTTG1IP in white blood cells of patients (responders n = 46, non-responders n = 51) at the time of diagnosis were comparatively analyzed by qRT-PCR. 3D scatter plot analysis combined with a distance analysis performed with respect to a commonly calculated centroid center resulted in a trend to larger distances for non-responders compared to the responder cohort (p = 0.0187). Logistic regression and analysis of maximum likelihood estimates revealed a positive correlation of distance (cut-off) with non-achieving MMR within 12 months (p = 0.0388, odds ratio 1.479, 95%CI: 1.020 to 2.143). Thus, 10% of the tested non-responders (cut-off ≥ 5.9) could have been predicted already at the time of diagnosis. Future scoring of ESPL1, PTTG1 and PTTG1IP transcript levels may be a helpful tool in risk stratification of CML patients before initiation of TKI first = line treatment.

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) of BCR-ABL1 transcript level is an essential part of routine disease monitoring in patients with chronic myeloid leukemia. One patient sample (e13a2 transcript detected by nested PCR) attracted attention by revealing an aberrantly spliced BCR-ABL1 transcript variant e13a1. The last 38 base pairs (bp) of BCR exon 13 were replaced by a 37 bp insertion of the ABL1 intron 1-2/exon 1 sequence. The rare aberrant BCR-ABL1 fusion transcript can cause discrepancies in molecular diagnostics. This scenario highlights the importance of an individual characterization of the BCR-ABL1 fusion sequence in case of unclear qRT-PCR results.

Background. The Aspergillus Galactomannan Lateral Flow Assay (LFA) is a rapid test for the diagnosis of invasive aspergillosis (IA) that has been almost exclusively evaluated in patients with hematologic malignancies. An automated digital cube reader that allows for quantification of results has recently been added to the test kits. Methods. We performed a retrospective multicenter study on bronchoalveolar lavage fluid (BALF) samples obtained from 296 patients with various underlying diseases (65% without underlying hematological malignancy) who had BALF galactomannan (GM) ordered between 2013 and 2019 at the University of California, San Diego, the Medical University of Graz, Austria, and the Mannheim University Hospital, Germany. Results. Cases were classified as proven (n = 2), probable (n = 56), putative (n = 30), possible (n = 45), and no IA (n = 162). The LFA showed an area under the curve (AUC) of 0.865 (95% confidence interval [CI].815-.916) for differentiating proven/probable or putative IA versus no IA, with a sensitivity of 74% and a specificity of 83% at an optical density index cutoff of 1.5. After exclusion of GM as mycological criterion for case classification, diagnostic performance of the LFA was highly similar to GM testing (AUC 0.892 vs 0.893, respectively). LFA performance was consistent across different patient cohorts and centers. Conclusions. In this multicenter study the LFA assay from BALF demonstrated good diagnostic performance for IA that was consistent across patient cohorts and locations. The LFA may serve a role as a rapid test that may replace conventional GM testing in settings where GM results are not rapidly available.

Separase, a cysteine endopeptidase, is a key player in mitotic sister chromatid separation, replication fork dynamics, and DNA repair. Aberrant expression and/or altered separase proteolytic activity are associated with aneuploidy, tumorigenesis, and disease progression. Since genomic instability and clonal evolution are hallmarks of progressing chronic myeloid leukemia (CML), we have comparatively examined separase proteolytic activity in TKI-treated chronic phase CML. Separase proteolytic activity was analyzed on single cell level in 88 clinical samples and in 14 healthy controls by a flow cytometric assay. In parallel, BCR-ABL1 gene expression and replication fork velocity were measured by qRT-PCR and DNA fiber assays, respectively. The separase activity distribution (SAD) value indicating the occurrence of MNCs with elevated separase proteolytic activity within samples was found to positively correlate with BCR-ABL1 gene expression levels and loss of MMR (relapse) throughout routine BCR-ABL1 monitoring. Analyses of CD34(+) cells and MNCs fractionized by flow cytometric cell sorting according to their separase activity levels (H- and L-fractions) revealed that CD34(+) cells with elevated separase activity levels (H-fractions) displayed enhanced proliferation/viability when compared with cells with regular (L-fraction) separase activity (mean 3.3-fold, p = 0.0011). BCR-ABL1 gene expression positivity prevailed in MNC H-fractions over L-fractions (42% vs. 8%, respectively). Moreover, expanding CD34(+) cells of H-fractions showed decreased replication fork velocity compared with cells of L-fractions (p < 0.0001). Our data suggests an association between high separase activity, residual BCR-ABL1 gene expression, and enhanced proliferative capacity in hematopoietic cells within the leukemic niche of TKI-treated chronic phase CML.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Radiation-induced bystander effects (RIBE) in human hematopoietic stem and progenitor cells may initiate myeloid neoplasms (MN). Here, the occurrence of RIBE caused by genotoxic signaling from irradiated human mesenchymal stromal cells (MSC) on human bone marrow CD34+ cells was investigated. For this purpose, healthy MSC were irradiated in order to generate conditioned medium containing potential genotoxic signaling factors. Afterwards, healthy CD34+ cells from the same donors were grown in conditioned medium and RIBE were analyzed. Increased DNA damage and chromosomal instability were detected in CD34+ cells grown in MSC conditioned medium when compared to CD34+ cells grown in control medium. Furthermore, reactive oxygen species and distinct proteome alterations, e.g., heat-shock protein GRP78, that might be secreted into the extracellular medium, were identified as potential RIBE mediators. In summary, our data provide evidence that irradiated MSC induce genetic instability in human CD34+ cells potentially resulting in the initiation of MN. Furthermore, the identification of key bystander signals, such as GRP78, may lay the framework for the development of next-generation anti-leukemic drugs.

In chronic myeloid leukemia (CML), the duration of deep molecular response (MR) before treatment cessation (MR4 or deeper, corresponding to BCR-ABL1 ≤ 0.01% on the International Scale (IS)) is considered as a prognostic factor for treatment free remission in stopping trials. MR level determination is dependent on the sensitivity of the monitoring technique. Here, we compared a newly established TaqMan (TM) and our so far routinely used LightCycler (LC) quantitative reverse transcription (qRT)-PCR systems for their ability to achieve the best possible sensitivity in BCR-ABL1 monitoring. We have comparatively analyzed RNA samples from peripheral blood mononuclear cells of 92 randomly chosen patients with CML resembling major molecular remission (MMR) or better and of 128 CML patients after treatment cessation (EURO-SKI stopping trial). While our LC system utilized ABL1, the TM system is based on GUSB as reference gene. We observed 99% concordance with respect to achievement of MMR. However, we found that 34 of the 92 patients monitored by TM/GUSB were re-classified to the next inferior MR log level, especially when LC/ABL1-based results were borderline to thresholds. Thirteen patients BCR-ABL1 negative in LC/ABL1 became positive after TM/GUSB analysis. In the 128 patients included in the EURO-SKI trial identical molecular findings were achieved for 114 patients. However, 14 patients were re-classified to the next inferior log-level by the TM/GUSB combination. Eight of these patients relapsed after treatment cessation; two of them were re-classified from MR4 to MMR and therefore did not meet inclusion criteria anymore. In conclusion, we consider both methods as comparable and interchangeable in terms of achievement of MMR and of longitudinal evaluation of clinical courses. However, in LC/ABL1 negative samples, slightly enhanced TM/GUSB sensitivity may lead to inferior classification of clinical samples in the context of TFR.

Funding information was incomplete. The correct information is given below.

Introduction: The single nucleotide polymorphism (SNP) rs460089 (G/C) located in the promotor of SLC22A4 (transporter hOCTN1) was identified as a prognostic factor for the outcome of chronic myeloid leukaemia patients treated with imatinib first line (Jaruskova et al. JECCR 2017). Patients with GC genotype had significantly higher probability of achievement of sustained major molecular response (MMR, BCR-ABL≤0.1% IS) as compared with patients with GG. We investigated differences in the outcome after imatinib cessation in EURO-SKI patients according to the genotypes of the SNP rs460089. Methods: DNA analysis was performed by TaqMan SNP genotyping assay using StepOnePlus RQ-PCR System (Thermofisher Scientific). In addition to the inclusion criteria defined for prognostic analysis in Saussele et al. (Lancet Oncology 2018), all patients with interferon pre-treatment were excluded. Data on sex, duration of IM treatment, of deep molecular response and age at time of imatinib discontinuation as well as molecular status at 6 months thereafter were available for 178 patients. Logistic regression was used to investigate factors affecting MMR maintenance at 6 months. Level of significance was 0.05. Results: Of 178 patients, 106 (60%) maintained MMR 6 months after imatinib stop. GC genotype was identified in 64 patients, GG in 96 and CC in 18. Most beneficial for MMR maintenance was genotype GC (72%, 95% confidence interval (CI): 60-82%), followed by CC (61%, CI: 38-80%) and GG (51%, CI: 41-61%). Overall, the SNP rs460089 was associated with MMR maintenance (p=0.0335) with a significantly higher odds ratio (OR) for maintenance for GC genotype vs. GG (2.451, CI: 1.247-4.819, p=0.0093) but not for CC vs. GG (1.507, CI: 0.539-4.216, p=0.4343). Only duration of TKI treatment was significant (OR: 1.157, CI: 1.014-1.319, p=0.0303) when added to genotypes in multiple regression. The OR of GC vs. GG was slightly modified to 2.311 (1.164-4.588, p=0.0166). Conclusions: Based on observed data we suppose that the GC genotype of the SNP rs460089 is associated with sufficient intracellular concentration of imatinib allowing more efficient targeting of CML cells during the treatment. This resulted in a higher proportion of patients who sustained MMR after imatinib stop as compared with patients with GG. Longer duration of imatinib treatment increased the probability of MMR maintenance after imatinib cessation also in patients with GG. The frequency of CC was low and outcome in between GC and GG. The SNP rs460089 may provide an independent prognostic factor for molecular response maintenance after imatinib cessation. Supported by MZCR 00023736. Disclosures Machova: Novartis: Consultancy; BMS: Consultancy, Research Funding; Incyte: Consultancy. Fabarius:Novartis: Research Funding. Brümmendorf:Pfizer: Consultancy, Research Funding; University Hospital of the RWTH Aachen: Employment; Merck: Consultancy; Ariad: Consultancy; Novartis: Consultancy, Research Funding; Janssen: Consultancy. Burchert:Novartis: Research Funding. Mustjoki:BMS: Honoraria, Research Funding; Novartis: Research Funding; Pfizer: Research Funding. Mayer:AOP Orphan Pharmaceuticals AG: Research Funding. Žáčková:Bristol Myers Squibb: Consultancy; Angelini: Consultancy; Incyte: Consultancy; Novartis: Consultancy. Panayiotidis:Bayer: Other: Support of clinical trial. Richter:Novartis: Consultancy; Pfizer: Consultancy, Research Funding. Hjorth-Hansen:BMS: Research Funding; Pfizer: Consultancy, Research Funding; Austrian Orphan Pharma: Consultancy, Research Funding. Saussele:Novartis: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Pfizer: Honoraria; Incyte: Honoraria, Research Funding.

SummaryInvasive aspergillosis (IA) is a severe complication in immunocompromised patients. Early diagnosis is crucial to decrease its high mortality, yet the diagnostic gold standard (histopathology and culture) is time‐consuming and cannot offer early confirmation of IA. Detection of IA by polymerase chain reaction (PCR) shows promising potential. Various studies have analysed its diagnostic performance in different clinical settings, especially addressing optimal specimen selection. However, direct comparison of different types of specimens in individual patients though essential, is rarely reported. We systematically assessed the diagnostic performance of an Aspergillus‐specific nested PCR by investigating specimens from the site of infection and comparing it with concurrent blood samples in individual patients (pts) with IA. In a retrospective multicenter analysis PCR was performed on clinical specimens (n = 138) of immunocompromised high‐risk pts (n = 133) from the site of infection together with concurrent blood samples. 38 pts were classified as proven/probable, 67 as possible and 28 as no IA according to 2008 European Organization for Research and Treatment of Cancer/Mycoses Study Group consensus definitions. A considerably superior performance of PCR from the site of infection was observed particularly in pts during antifungal prophylaxis (AFP)/antifungal therapy (AFT). Besides a specificity of 85%, sensitivity varied markedly in BAL (64%), CSF (100%), tissue samples (67%) as opposed to concurrent blood samples (8%). Our results further emphasise the need for investigating clinical samples from the site of infection in case of suspected IA to further establish or rule out the diagnosis.

In hematological patients, the incidence of invasive aspergillosis (IA) caused by azole resistant Aspergillus fumigatus (ARAf) is rising. As the diagnosis of IA is rarely based on positive culture in this group of patients, molecular detection of resistance mutations directly from clinical samples is crucial. In addition to the in-house azole resistance ARAf polymerase chain reaction (PCR) assays detecting the frequent mutation combinations TR34/L98H, TR46/Y121F/T289A, and M220 in the Aspergillus fumigatus (A. fumigatus) Cyp51A gene by subsequent DNA sequence analysis, we investigated in parallel the commercially available AsperGenius® real time PCR system in detecting the Cyp51A alterations TR34/L98H and Y121F/T289A directly from 52 clinical samples (15 biopsies, 22 bronchoalveolar lavage (BAL), 15 cerebrospinal fluid (CSF) samples) and ARAf isolates (n = 3) of immunocompromised patients. We analyzed DNA aliquots and compared both methods concerning amplification and detection of Aspergillus DNA and Cyp51A alterations. As positive control for the feasibility of our novel Y121F and T289A PCR assays, we used two A. fumigatus isolates with the TR46/Y121F/T289A mutation combination isolated from hematological patients with known Cyp51A alterations and a lung biopsy sample of a patient with acute myeloid leukemia (AML). The rate of positive ARAf PCR results plus successful sequencing using the ARAf PCR assays was 61% in biopsies, 29% in CSF, 67% in BAL samples and 100% in isolates. In comparison the amount of positive PCRs using the AsperGenius® assays was 47% in biopsies, 42% in CSF, 59% in BAL samples and 100% in isolates. Altogether 17 Cyp51A alterations were detected using our ARAf PCRs plus DNA sequencing and therefrom 10 alterations also by the AsperGenius® system. The comparative evaluation of our data revealed that our conventional PCR assays are more sensitive in detecting ARAf in BAL and biopsy samples, whereby differences were not significant. The advantage of the AsperGenius® system is the time saving aspect. We consider non-culture based molecular detection of Aspergillus triazole resistance to be of high epidemiological and clinical relevance in patients with hematological malignancies.

Background: Aspergillus spp. induce elevated levels of several cytokines. It remains unknown whether these cytokines hold value for clinical routine and enhance diagnostic performances of established and novel biomarkers/tests for invasive aspergillosis (IA). Methods: This cohort study included 106 prospectively enrolled (2014-2017) adult cases with underlying hematological malignancies and suspected pulmonary infection undergoing bronchoscopy. Serum samples were collected within 24 hours of bronchoalveolar lavage fluid (BALF) sampling. Both, serum and BALF samples were used to evaluate diagnostic performances of the Aspergillus-specific lateral-flow device test (LFD), Aspergillus PCR, beta-D-glucan, and cytokines that have shown significant associations with IA before. Results: Among 106 cases, 11 had probable IA, and 32 possible IA; 80% received mold-active antifungals at the time of sampling. Diagnostic tests and biomarkers showed better performance in BALF versus blood, with the exception of serum interleukin (IL)-8 which was the most reliable blood biomarker. Combinations of serum IL-8 with either BALF LFD (sensitivity 100%, specificity 94%) or BALF PCR (sensitivity 91%, specificity 97%) showed promise for differentiating probable IA from no IA. Conclusions: High serum IL-8 levels were highly specific, and when combined with either the BALF Aspergillus-specific LFD, or BALF Aspergillus PCR also highly sensitive for diagnosis of IA. (C) 2018 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Therapy of invasive aspergillosis is becoming more difficult due to the emergence of azole resistance in Aspergillus fumigatus. A majority of resistant strains carries mutations in the CYP51A gene. Due to a lack of sensitivity of culture-based methods, molecular detection of A. fumigatus has become an important diagnostic tool. We set up the database FunResDB (www.nrz-myk.de/funresdb) to gather all available information about CYP51A-dependent azole resistance from published literature. In summary, the screening resulted in 79 CYP51A variants, which are linked to 59 nonsynonymous mutations. A tailor-made online sequence analysis tool allows for genotypic susceptibility testing of A. fumigatus.

Quantitative real-time polymerase chain reaction (qRT-PCR) is state of the art in molecular monitoring of minimal residual disease in chronic myeloid leukemia (CML). In this context, maintenance of assay fidelity and detection of technical inaccuracy are crucial. Beside multiple common negative controls for the clinical sample preparations, quality control charts (QCC) are a common validation tool to sustain high process quality by continuously recording of qRT-PCR control parameters. Here, we report on establishment and benefit of QCC in qRT-PCR-based CML diagnostics. The absolute quantification of BCR-ABL1 fusion transcripts in patient samples is based on coamplification of a serially diluted reference plasmid (pME-2). For QCC establishment the measured Ct values of each pME-2 standard dilution (4-400,000) of a test set resembling 21 sequential qRT-PCR experiments were recorded and statistically evaluated. Test set data were used for determination of warning limits (mean +/- 2-fold standard deviation) and control (intervention) limits (mean +/- 3-fold standard deviation) to allow rapid detection of defined out-of-control situations which may require intervention. We have retrospectively analyzed QCC data of 282 sequential qRT-PCR experiments (564 reactions). Data evaluation using QCCs revealed three out-of-control situations that required intervention like experiment repeats, renewal of pME-2 standards, replacement of reagents or personnel re-training. In conclusion, with minimal more effort and hands-on time QCC rank among the best tools to grant high quality and reproducibility in CML routine molecular diagnosis.

Abstract Background Aspergillus spp. induce elevated levels of several cytokines, including Interleukin (IL)-6 and IL-8. It remains unknown whether these cytokines hold value for clinical routine and enhance diagnostic performances of established and novel biomarkers/molecular tests for invasive aspergillosis (IA) in patients receiving mold-active antifungals. Methods This cohort study included 106 prospectively enrolled (2014–2017) adult cases with underlying hematological malignancies and suspected pulmonary infection undergoing bronchoscopy. Serum samples were collected within 24 hours of bronchoalveolar lavage fluid (BALF) sampling. Both serum and BALF samples were used to evaluate diagnostic performances of the Aspergillus-specific lateral-flow device test (LFD), Aspergillus PCR, galactomannan, β-d-glucan, and cytokines that have shown significant associations with IA in our previous matched case–control analysis (including IL-6 and IL-8), for IA classified according to the revised EORTC/MSG criteria. Results Among the 106 cases, 11 had probable IA, 32 possible IA, and 63 no evidence for IA; 80% received mold-active antifungals at the time of sampling. Diagnostic tests and biomarkers showed significantly better performance in BALF compared with blood, with the exception of serum IL-8 which was highly specific for IA and proved to be the most reliable blood biomarkers. Combinations of serum IL-8 with either BALF LFD (sensitivity 100%, specificity 94%) or BALF PCR (sensitivity 91%, specificity 97%) were highly sensitive and specific for differentiating probable IA from no IA. Conclusion High serum IL-8 levels were highly specific, and when combined with either the BALF Aspergillus-specific LFD, or BALF Aspergillus PCR also highly sensitive for diagnosis of IA. Disclosures G. Johnson, OLM Diagnostics: Employee, Salary.