Spectrum of adult Parvovirus B19 infection according to the underlying predisposing condition and proposals for clinical practice.

The virological diagnosis of Parvovirus B19 (PvB19) infection is currently based on sero-diagnosis, molecular methods or both, yet without clear recommendations. We retrospectively identified patients with polymerase chain reaction-positive PvB19 and/or positive serological assay between 2007 and 2013. Eighty-two adults with at least one diagnostic criterion of recent PvB19 infection (IgM antibodies, viral DNA in blood and/or in marrow) were included and classified into three homogeneous groups: 30 patients had no underlying predisposing condition, 25 a hereditary haemolytic anaemia, 27 an underlying immunodeficiency. The classical PvB19-related manifestations were less frequent in immunocompromised than in immunocompetent patients (arthromyalgia: 5 vs. 14; erythema: 4 vs. 17, respectively). Only 41·4% of patients with no underlying disease were anaemic. Bicytopenia and pancytopenia were observed mainly in immunocompromised patients. Classical pure red cell aplasia was observed in only 9 of the 27 marrow smears performed. Specific IgM were found in 93% of immunocompetent patients, whereas only 58% had detectable viral DNA in blood. IgM and DNA were present alone or together in all patients with hereditary haemolytic anaemia. In immunocompromised patients, the diagnosis was confirmed by marrow analysis in 91% of cases. We make some proposals based on this large series of PvB19-infected patients.

Flow cytometry thresholds of myeloperoxidase detection to discriminate between acute lymphoblastic or myeloblastic leukaemia.

The World Health Organization 2008 Classification emphasizes myeloperoxidase (MPO) detection as sufficient for assigning a blast population to the myeloid lineage. Published MPO positivity thresholds are 10% for flow cytometry (FCM) but 3% for cytochemistry. Here we re-evaluated the FCM-MPO threshold by comparing retrospectively 128 acute lymphoblastic leukaemias and 75 acute myeloid leukaemias without maturation, all assessed by benzidine-based cytochemistry. A 13% threshold was found to be relevant using an isotype control as background-reference (sensitivity 95·1%, specificity 91·7%). Residual normal lymphocytes proved to be an advantageous alternative reference, a threshold of 28% yielding improved 97·4% sensitivity and 96·1% specificity.

Peripheral blood findings in chronic myeloproliferative disorders.

Chronic myeloproliferative disorders are now frequently detected on routine total blood count. A careful analysis of PB smears allows the diagnosis in many cases, and helps to classify most of them. The peripheral blood parameters may be of prognostic value, especially in AMM. During the follow-up of CMPD, modifications of the PB are of great interest to detect an evolution toward a myelofibrosis or a blastic phase.

Hematological reference values for healthy adults in togo.

The hematological reference values are very important for diagnostic orientation and treatment decision. The aim of this study was to establish hematological reference values for healthy adults in Togo. A total of 2571 voluntary blood donors participated to this study. Only 1349 subjects negative for HIV, HBV, HCV, malaria, and without hemoglobin abnormalities in electrophoresis and hypochromia on blood smear, were definitively retained for the study. Median hemoglobin level was higher in males than females (15.1 g/dL versus 13.0 g/dL, p = 0.000). Median total WBC (4.2×10(9)/L) and absolute neutrophil counts (1.6×10(9)/L) were similar by gender. The median lymphocyte counts in males and females were, respectively, 2.1×10(9)/L and 2.2×10(9)/L (p = 0.11). The median platelet count was lower in males than females (236×10(9)/L versus 247×10(9)/L, p = 0.004). Our median values for RBC parameters differ from those of African countries probably because of our inclusion criteria which eliminate most cases with iron deficiency and/or thalassemia.

Immunophenotypic clustering of myelodysplastic syndromes.

Myelodysplastic syndromes (MDSs) are heterogeneous diseases of bone marrow (BM) cell precursors for which immunophenotypic characterization is still considered irrelevant despite the accuracy and sensitivity of flow cytometry techniques. The aim of this study was to determine whether immunophenotypic abnormalities could be defined in MDSs and could correlate with the French-American-British classification and cytogenetics. Analysis was performed on 275 BM samples (207 MDS patients, 68 controls) and 25 control blood samples. Immunophenotyping was based on a primary gating of blast cells, monocytes, and granulocytes according to CD45 antigen expression and side scatter light diffraction. Immunophenotypic hierarchical clustering was performed to analyze the results. The data obtained show that (1) immunophenotypic clustering partly discriminates patients with refractory anemia with excess blasts/refractory anemia with excess blasts in transformation (RAEB/RAEB-T), chronic myelomonocytic leukemia (CMML), and refractory anemia/refractory anemia with ring sideroblasts (RA/RARS) for CD45(lo) blast cells and patients with RA/CMML, RARS, and RAEB/RAEB-T for CD45(hi)/side scatter(hi) (SS(hi)) granulocytes; (2) the most discriminating markers were CD16, CD34, CD36, CD38, CD71, and HLA-DR for blast cells and CD11b, CD13, CD33, CD36, CD38, CD71, and HLA-DR for CD45(hi)/SS(hi) granulocytes; (3) clusters related to CD34 expression were associated with high levels of blast cells on BM smear; (4) clusters related to high levels of CD36 expression on CD45(lo) blast cells and CD45(hi)/SS(hi) granulocytes were associated with a poor International Prognosis Scoring System score; and (5) high levels of CD71 expression on CD45(hi)/SS(hi) granulocytes were associated with the RARS category. These results show a close relationship between immunophenotypic abnormalities and BM dysplasia and suggest that flow cytometry could be a future tool for the characterization of MDSs.