Zdenek Racil

Difficulties in using 1,3-β-d-glucan as the screening test for the early diagnosis of invasive fungal infections in patients with haematological malignancies – high frequency of false-positive results and their analysis

We have evaluated the contribution of the 1,3-beta-d-glucan (BG) assay for the screening of invasive fungal infections (IFIs) in patients with haematological malignancies. Serum samples from patients at risk of IFI were collected twice a week and retrospectively tested using the BG assay. BG screening was performed on 1143 samples from 91 patients during 104 anticancer treatment cycles. Proven and probable cases of IFI occurred in 9 (8.7 %) treatment cycles. Depending on the criterion of positivity used (1x >60 pg ml(-1), 1x >80 pg ml(-1), 2x >60 pg ml(-1) or 2x >80 pg ml(-1)) the sensitivity and specificity were 89, 89, 67 and 44 %, and 20, 48, 33 and 56 %, respectively. Although the test was marked as positive in 82, 68, 54 and 45 % of all the treatment cycles, in the majority of cases, these positivities were probably false. The major limit of the BG test was an extremely low positive predictive value (10 to 12 %). We have analysed mucositis, candida colonization, bacteraemia, use of antimicrobials, erythrocyte and thrombocyte filtered blood products, collecting tubes or sampling via venous catheters. Even though no factor is a major source of BG, it could at least partially influence BG assay performance. Thus, BG detection has a limited usefulness as a screening method for IFIs in patients with haematological malignancies.

Combined antifungal approach for the treatment of invasive mucormycosis in patients with hematologic diseases: a report from the SEIFEM and FUNGISCOPE registries.

Invasive mucormycosis (IM) in patients with acute leukemia and allogeneic stem cell transplant (allo-SCT) recipients treated with antifungal monotherapy is associated with high mortality rates of 44–49%.[1][1]–[3][2] Among the available antifungals, amphotericin B (AmB) formulations and

Monitoring trough voriconazole plasma concentrations in haematological patients: real life multicentre experience.

The objective of this retrospective study was to evaluate results from voriconazole therapeutic drug monitoring (TDM) in haematological patients in routine clinical practice. Between 2005 and 2010, 1228 blood samples were obtained from 264 haematological patients (median 3 samples/patient; range 1–27) receiving voriconazole for targeted/preemptive treatment of invasive aspergillosis (IA) (46.3% of samples), empirical therapy (12.9%) or prophylaxis (40.8%). A high‐pressure liquid chromatography assay was used to analyse voriconazole concentrations. Clinical and laboratory data were analysed retrospectively. The median of the detected voriconazole plasma concentration was 1.00 μg ml−1 (range <0.20–13.47 μg ml−1). Significant inter‐ and intra‐patients variability of measured concentrations (81.9% and 50.5%) were identified. With the exception of omeprazole administration, there was no relevant relationship between measured voriconazole concentrations and drug dose, route administration, age, gender, CYP2C19*2 genotype, gastrointestinal tract abnormality, administration via nasogastric tube, serum creatinine, and liver enzymes. However, per patient analysis identified significant role of individual voriconazole dose and drug form change on measured plasma concentration. Measured voriconazole concentrations did not correlate with the treatment outcome of patients with IA. We only identified a limited number of adverse events related to voriconazole therapy; however, the median plasma concentration was not different from concentrations measured in samples without reported toxicity. Our retrospective study has suggested that routine monitoring of voriconazole plasma concentrations has probably only a limited role in daily haematological practice.

Intravenous PLASMA-LYTE as a major cause of false-positive results of platelia Aspergillus test for galactomannan detection in serum

Galactomannan (GM) detection by the Platelia Aspergillus (PA) enzyme immunoassay (Bio-Rad, France) is a test widely used for the early diagnosis of invasive aspergillosis (IA) in hematooncological patients. False-positive results for this test were reported by several authors, associated mainly with

Mechanism of impaired glucose metabolism during nilotinib therapy in patients with chronic myelogenous leukemia

Hyperglycemia represents frequent adverse event reported in chronic myelogenous leukemia (CML) patients treated with nilotinib. In order to determine the major mechanism of glucose metabolism impairment, we performed a metabolic analysis using an oral glucose tolerance test as well as assessment of incretins and adipokines at baseline and after 3 months of nilotinib treatment in patients with CML. We proved that rapid insulin resistance, compensatory hyperinsulinaemia, and hypoadiponectinaemia develop after initiation of nilotinib therapy, which clarifies not only the mechanism of impaired glucose metabolism, but also explains the fast development of dyslipidaemia and peripheral artery occlusion in nilotinib-treated CML patients.

Rapid Detection and Identification of Mucormycetes from Culture and Tissue Samples by Use of High-Resolution Melt Analysis

ABSTRACT We present a method for rapid and simple detection of clinically relevant mucormycetes of the Mucorales order in cultures and clinical samples. This seminested real-time PCR uses mucormycete-specific primers and is followed by species identification using high-resolution melt (HRM) analysis. The method is highly suitable for routine clinical diagnostics.

Monitoring of minimal residual disease in acute myeloid leukemia with frequent and rare patient‐specific NPM1 mutations

Nucleophosmin (NPM1) mutations in exon 12 are the most common genetic alternation in cytogenetically normal AML (CN‐AML). Although mutation types A, B, and D represent the majority of cases, rare mutation variants of the NPM1 gene in individual patients do occur. In this study, we have evaluated a novel, DNA‐based real‐time quantitative polymerase chain reaction (RQ‐PCR) for the detection of three of the most commonly occurring mutations and for six rare patient‐specific mutation types, which represent 28% of all of the NPM1 mutations in our group of 25 CN‐AML patients. Furthermore, the prognostic relevance of NPM1‐based monitoring of minimal residual disease (MRD) in peripheral blood (PB), bone marrow (BM), and in specific cell subsets (CD34+, CD34−, CD34dim) of BM were evaluated. In 80% of the evaluable patients, a molecular relapse preceded a hematological relapse. Moreover, in this subset of patients, the molecular relapse occurred at a median of 97 days before the hematological relapse. Our compartment analysis showed a strong correlation between BM and PB (r = 0.907, P < 0.001) as well as a high copy number of mutated NPM1 in CD34+ BM cells. In conclusion, we have demonstrated applicability of our presented RQ‐PCR method for a large percentage of mutated NPM1 patients with CN‐AML as well as the usefulness for long‐term follow‐up monitoring of MRD and the prediction of hematological relapse. Am. J. Hematol., 2010.

Detection and Measurement of Fungal Burden in a Guinea Pig Model of Invasive Pulmonary Aspergillosis by Novel Quantitative Nested Real-Time PCR Compared with Galactomannan and (1,3)-β-d-Glucan Detection

ABSTRACT We developed and assessed the diagnostic value of a novel quantitative nested real-time (QNRT) PCR assay targeting the internal transcribed spacer region of ribosomal DNA (rDNA) in a guinea pig model of invasive pulmonary aspergillosis. Groups of 5 immunosuppressed animals that were infected using an aerosol chamber with Aspergillus fumigatus conidia were humanely terminated 1 h postinoculation and at days 3, 5, 7, and 11 postchallenge, and lung tissue, bronchoalveolar lavage (BAL) fluid, whole blood, and serum samples were collected. The QNRT PCR results obtained with the serum and BAL fluid were compared to those achieved with galactomannan and (1→3)-β-d-glucan assays. High fungal burden levels were detected by QNRT PCR in both lung tissue and BAL fluid in all infected animals at each time point, and the sensitivity of each assay in BAL fluid was 100% by day 3 and remained so through the remainder of the study. The sensitivity of detection of fungi in whole blood and serum samples was significantly lower, and some samples remained negative by all three assays despite the advanced stage of the infection. From these data, we can conclude that this novel QNRT PCR method was highly sensitive for the detection of A. fumigatus from different types of samples in this model. In addition, BAL fluid samples appeared to be the most suitable for the early diagnosis of invasive pulmonary aspergillosis. When testing serum, the use of a combination of available assays may increase the possibility of early detection of this opportunistic mycosis.

Rapid Detection and Identification of Mucormycetes in Bronchoalveolar Lavage Samples from Immunocompromised Patients with Pulmonary Infiltrates by Use of High-Resolution Melt Analysis

ABSTRACT Rapid differential diagnostics of pulmonary infiltrates suspected of invasive fungal disease in an immunocompromised host and early initiation of effective antifungal therapy are crucial for patient outcomes. There are no serological tests available to detect mucormycetes; therefore, PCR-based methods are highly suitable. We validated our previously published PCR followed by high-resolution melt analysis (PCR/HRMA) to detect Rhizopus spp., Rhizomucor pusillus, Lichtheimia corymbifera, and Mucor spp. in bronchoalveolar lavage (BAL) samples from immunocompromised patients who were at risk of invasive fungal disease. All PCR/HRMA-positive samples were retested using novel real-time quantitative PCR (RQ PCR) assays specific to the species identified. In total, between January 2009 and December 2012 we analyzed 99 BAL samples from 86 patients with pulmonary abnormalities using PCR/HRMA. Ninety (91%) BAL samples were negative, and 9 (9%) samples were positive. The sensitivity and specificity of PCR/HRMA were 100% and 93%, respectively. By combining the positive results of PCR/HRMA with positive RQ PCR results, the specificity was raised to 98%. PCR/HRMA, due to its high negative predictive value (99%), represents a fast and reliable tool for routine BAL sample screening for the differential diagnosis of pulmonary infiltrates in immunocompromised patients for the four most clinically important mucormycetes.

Reactivity of the 1,3-β-D-glucan assay during bacteraemia: limited evidence from a prospective study

There are discrepancies in the retrospective studies published in literature of whether or not bacteraemia could lead to false positivity of 1,3‐β‐D (BG) glucan assay. We performed, for the first time, a prospective study evaluating the role of bacterial bloodstream infection to the reactivity of BG assay. Twenty‐six episodes of bacteraemia that occurred in high‐risk haematological patients were included in our study. Consecutive BG levels >80 pg ml−1 were required for test positivity. Only 2 of 26 patients were BG positive – both with IFDs. Thus, we prospectively did not prove bacteraemia as the source of cross reactivity of BG assay in haematological patients.