An international working group within the European LeukemiaNet gathered, aiming to determine the role of flow cytometry (FC) in myelodysplastic syndromes (MDS). It was agreed that FC has a substantial application in disease characterization, diagnosis and prognosis. FC may also be useful in predicting treatment responses and monitoring novel and standard therapeutic regimens. In this article the rationale is discussed that flow cytometry should be integrated as a part of diagnostic and prognostic scoring systems in MDS.

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Conclusions: The high correlation between genotypic and phenotypic abnormalities suggests a possible increased utility of flow cytometry in the diagnosis of patients with unexplained cytopenias and may be useful in future clinical studies and in the classification by the WHO, using the FCSS rather than simple counting of flow cytometric abnormalities.

Background: Detection of basal levels of CD34 progenitor cells is a rare event analysis enumerating cells down to 1 cell/ll. A reproducible analytic approach was used in three independent clinical trials in which multiple sequential assays were obtained from the same individual.Methods: A 4 color panel combining, HLA-DR, CD34, CD45, and CD11b was used in a dual platform analysis to quantify CD34 progenitor cells in peripheral blood, with quality control focused at the lowest measurements (i.e., basal levels), where assay error is greatest.Results: Repeat testing of individuals every 4 h over the course of 6 days provided a unique opportunity to assess the precision of the analytic technique and identified basal differences between individuals. In a second study, the basal levels were stable for 10 weeks while in a third study the individual differences were maintained for 18 months. This approach was then used to monitor the kinetics of mobilization of CD34 cells following G-CSF stimulation every 4 h.Conclusions: The differences between individuals in basal levels of CD34 were shown to be a biologic constant, stable for 18 months and not a result of the variability of the assay, shown by low coefficients of variation for each individual. These results can be used to augment a quality control program by monitoring individuals over time to establish intra and inter-laboratory assay precision. In addition, the response of six individuals to G-CSF demonstrated differences in absolute numbers of mobilized CD34 progenitor cells but showed identical kinetics, peaking at 80-110 h. V C 2011 International Clinical Cytometry Society

More than 40 human cases of severe encephalitis caused by Borna disease virus 1 (BoDV-1) have been reported to German health authorities. In an endemic region in southern Germany, we conducted the seroepidemiological BoSOT study (“BoDV-1 after solid-organ transplantation”) to assess whether there are undetected oligo- or asymptomatic courses of infection. A total of 216 healthy blood donors and 280 outpatients after solid organ transplantation were screened by a recombinant BoDV-1 ELISA followed by an indirect immunofluorescence assay (iIFA) as confirmatory test. For comparison, 288 serum and 258 cerebrospinal fluid (CSF) samples with a request for tick-borne encephalitis (TBE) diagnostics were analyzed for BoDV-1 infections. ELISA screening reactivity rates ranged from 3.5% to 18.6% depending on the cohort and the used ELISA antigen, but only one sample of a patient from the cohort with requested TBE diagnostics was confirmed to be positive for anti-BoDV-1-IgG by iIFA. In addition, the corresponding CSF sample of this patient with a three-week history of severe neurological disease tested positive for BoDV-1 RNA. Due to the iIFA results, all other results were interpreted as false-reactive in the ELISA screening. By linear serological epitope mapping, cross-reactions with human and bacterial proteins were identified as possible underlying mechanism for the false-reactive ELISA screening results. In conclusion, no oligo- or asymptomatic infections were detected in the studied cohorts. Serological tests based on a single recombinant BoDV-1 antigen should be interpreted with caution, and an iIFA should always be performed in addition.