Pancytopenia related to acquired sea-blue histiocytosis during chronic parenteral nutrition.

Bone marrow smear showing histiocytes (black arrow) containing sea blue granules stained with May-Grünwald Giemsa.

Massive circulating metastatic cells: A case of carcinocythemia.

Importance of careful differential diagnosis to make the distinction between carcinocythemia and acute leukemia or lymphoma.

White blood cells scattergram as a valuable tool for COVID-19 screening: A multicentric study.

INTRODUCTION: New tools have been developed to distinguish the COVID-19 diagnosis from other viral infections presenting similar symptomatology and mitigate the lack of sensitivity of molecular testing. We previously identified a specific "sandglass" aspect on the white blood cells (WBC) scattergram of COVID-19 patients, as a highly reliable COVID-19 screening test (sensitivity: 85.9%, specificity: 83.5% and positive predictive value: 94.3%). We then decided to validate our previous data in a multicentric study. METHODS: This retrospective study involved 817 patients with flu-like illness, among 20 centers, using the same CBC instrument (XN analyzer, SYSMEX, Japan). After training, one specialist per center independently evaluated, under the same conditions, the presence of the "sandglass" aspect of the WDF scattergram, likely representing plasmacytoid lymphocytes. RESULTS: Overall, this approach showed sensitivity: 59.0%, specificity: 72.9% and positive predictive value: 77.7%. Sensitivity improved with subgroup analysis, including in patients with lymphopenia (65.2%), patients presenting symptoms for more than 5 days (72.3%) and in patients with ARDS (70.1%). COVID-19 patients with larger plasmacytoid lymphocyte cluster (>15 cells) more often have severe outcomes (70% vs. 15% in the control group). CONCLUSION: Our findings confirm that the WBC scattergram analysis could be added to a diagnostic algorithm for screening and quickly categorizing symptomatic patients as either COVID-19 probable or improbable, especially during COVID-19 resurgence and overlapping with future influenza epidemics. The observed large size of the plasmacytoid lymphocytes cluster appears to be a hallmark of COVID-19 patients and was indicative of a severe outcome. Furthers studies are ongoing to evaluate the value of the new hematological parameters in combination with WDF analysis.

Cold agglutinin disease secondary to severe SARS-CoV-2 treated with eculizumab.

Impaired immune response with uncontrolled inflammation and various immunological disorders have been reported during SARS-CoV-2 infection. Here, we report a case of cold agglutinin disease occurring during a severe coronavirus disease 2019 (COVID-19) in a French intensive care unit. A patient was presented with acute respiratory distress syndrome, acute renal failure and haemolytic anaemia. Direct antiglobulin test was positive with a cold agglutinin titre of 1/512. No other cause than COVID-19 explained the occurrence of cold agglutinin disease; however, causality could not be formally established. Persistent anaemia despite transfusion therapy and the short-term life-threatening, prompted the infusion of a monoclonal anti-C5 antibody (eculizumab). Eculizumab therapy quasi-fully resolved haemolysis within a few days, but ultimately the patient died from his severe COVID-19 infection. Data regarding the specific treatment of cold agglutinin disease during COVID-19 are rare. Although additional studies are warranted, eculizumab may be considered in critical situations.

Interferon Alpha Therapy Increases Pro-Thrombotic Biomarkers in Patients with Myeloproliferative Neoplasms.

Myeloproliferative neoplasms (MPN) are associated with an increased risk of arterial and venous thrombosis. Pegylated-interferon alpha (IFN) and hydroxyurea (HU) are commonly used to treat MPN, but their effect on hemostasis has not yet been studied. The aim of our study was to determine whether IFN and HU impact the biological hemostatic profile of MPN patients by studying markers of endothelial, platelet, and coagulation activation. A total of 85 patients (50 polycythemia vera and 35 essential thrombocythemia) were included: 28 treated with IFN, 35 with HU, and 22 with no cytoreductive drug (non-treated, NT). Von Willebrand factor, shear-induced platelet aggregation, factor VIII coagulant activity (FVIII:C), fibrinogen, and thrombin generation with and without exogenous thrombomodulin were significantly higher in IFN-treated patients compared to NT patients, while protein S anticoagulant activity was lower. In 10 patients in whom IFN therapy was discontinued, these hemostatic biomarkers returned to the values observed in NT patients, strongly suggesting an impact of IFN therapy on endothelial and coagulation activation. Overall, our study shows that treatment with IFN is associated with significant and reversible effects on the biological hemostatic profile of MPN patients. Whether they could be associated with an increased thrombotic risk remains to be determined in further randomized clinical studies.

[A case of bone marrow necrosis and fat embolism in a sickle-cell disease patient]. / Un cas de nécrose médullaire compliquée d'embolie graisseuse chez un patient drépanocytaire.

We report here a case of bone marrow necrosis and fat embolism syndrome in a 23-year-old sickle-cell disease (HbSS) patient. A brutal and severe bicytopenia conducted to suspect bone marrow necrosis, confirmed by bone marrow aspiration and analysis. This was the first life-threatening medical event for this patient. In the present case, a complex alloimmunization against blood group antigens complicated the treatment because of the risks associated with the transfusion strategy. These rare complications of sickle-cell disease may be fatal, but an efficient symptomatic treatment generally allows for recovery. Medical biologists should be aware of the danger of bone marrow necrosis in sickle-cell disease, so that they can help clinicians and accurately diagnose this serious complication.

[Lymphoplasmacytic lymphoma or multiple myeloma: immunoglobulins may lead to misdiagnosis]. / Lymphome lymphoplasmocytaire ou myélome multiple : quand les immunoglobulines induisent en erreur.

We report here a case of lymphoplasmacytic lymphoma with IgA paraproteinemia and a case of concomitant Waldenström macroglobulinemia and monoclonal gammapathy of unknown significance. These rare cases show that the isotype of a monoclonal immunoglobulin does not allow to foresee every time the underlying pathology. Clinical data and medical imaging are essential. From a biological point of view, additional analysis such as immunophenotyping, cytogenetics and molecular biology are required in addition to the cytological features in order to make an accurate differential diagnosis between lymphoid and plasma cell malignancy.

A case of EDTA-related in vitro platelet degranulation.

A 71 year-old woman is admitted to Le Mans hospital center for management of a chronic skin lesion. She has no personal nor familial bleeding history and does not take any medication. In peripheral blood collected with EDTA (ethylene diamine tetra-acetate), the platelet count is elevated and the blood film shows uniformly grey platelets. In sodium citrate-collected blood, platelets show no abnormality. We describe an EDTA-related artifact that is not to be mistaken for grey platelet syndrome.