Thrombophilia risk is not increased in children after perinatal stroke.

Perinatal stroke causes cerebral palsy and lifelong disability. Specific diseases are definable, but mechanisms are poorly understood. Evidence suggests possible associations between arterial perinatal stroke and prothrombotic disorders, but population-based, controlled, disease-specific studies are limited. Understanding thrombophilia in perinatal stroke informs pathogenesis models and clinical management. We conducted a population-based, prospective, case-control study to determine the association of specific perinatal stroke diseases with known thrombophilias. Children with idiopathic magnetic resonance imaging-classified neonatal arterial ischemic stroke (NAIS), arterial presumed perinatal ischemic stroke (APPIS), or fetal periventricular venous infarction (PVI) were recruited. Standardized thrombophilia evaluations were performed after 12 months of age on stroke cases and controls, including quantified proteins C and S, antithrombin, factors VIII/IX/XI, fibrinogen, lipoprotein(a), homocysteine, lupus anticoagulant, anticardiolipin antibodies and genotyping of factor V Leiden (FVL), factor II G20210A (FII), and methylenetetrahydrofolate reductase C677T. A total of 212 children were studied: 46 with NAIS, 34 with APPIS, 55 with PVI, and 77 controls (male, 53%; median age, 4.8 years). Of 14 parameters, no differences were observed in 12, including all common thrombophilias. Mean prothrombin time was shorter in arterial strokes (P < .001). Rates of antiphospholipid antibodies were low, comparable to those in controls, and resolved on repeat testing. FVL and FII rates were comparable to population norms. Total number of possible abnormalities did not differ between cases and controls. Our prospective, population-based, controlled, disease-specific study suggests minimal association between perinatal stroke and thrombophilia. This does not exclude the possibility of disordered coagulation at the time of stroke but suggests testing in childhood is not indicated.

Artifactual Kappa Light Chain Restriction of Marrow Hematogones: A Potential Diagnostic Pitfall in Minimal Residual Disease Assessment of Plasma Cell Myeloma Patients on Daratumumab.

BACKGROUND: Daratumumab (DARA) is a humanized Immunoglobulin G(IgG)1-kappa monoclonal antibody against CD38 antigen that is shown to improve outcomes in relapsed/refractory plasma cell myeloma (PCM) patients. Since CD38 is expressed by different hematopoietic elements, DARA has the potential to interfere with flow cytometric assessment of bone marrow specimens. METHODS: Flow cytometric analysis of bone marrow samples from 10 PCM on DARA and 5 control samples was performed using two different antibody panels. RESULTS: Bone marrow samples from PCM patients on DARA exhibited a population of CD19+ CD10+ B-lymphoid cells with kappa light chain restriction. Further morphological and immunophenotypic studies suggested that this population represents marrow hematogones. Marrow hematogones from control samples showed normal immunophenotypic profiles. CONCLUSION: DARA on the surface of hematogones interferes with flow cytometric clonality study leading to artifactual kappa light chain restriction, which can result in false interpretation of a concurrent clonal B-cell proliferation. In the era of rapidly growing list of therapeutic monoclonal antibodies, flow cytometry pathologists should be aware of potential interferences to avoid misdiagnosis. © 2019 International Clinical Cytometry Society.

Human granulocytic anaplasmosis: First reported case in Canada.

Human granulocytic anaplasmosis (HGA) is a tick-borne rickettsial infection of peripheral blood neutrophils caused by Anaplasma phagocytophilum. While this infection is increasingly recognized as endemic throughout much of the United States, no Canadian cases have been previously described, despite the agent being identified in Canadian ticks. Herein we present a case of HGA acquired in an urban Alberta centre. Canadian physicians must be aware of the possibility of tick-borne rickettsial diseases as etiology of fever in individuals presenting with leukopenia/lymphopenia, thrombocytopenia and elevated transaminases during periods of tick activity. Prompt recognition and treatment are important in minimizing resultant morbidity and mortality.