Abstract Background Clonal mast cell disorders are known to occur in a subset of patients with systemic reactions to Hymenoptera stings. This observation has prompted the question as to whether ...clonal mast cell disorders also occur in patients with idiopathic anaphylaxis (IA). Objective We sought to determine the prevalence of clonal mast cell disorders among patients with IA, criteria to identify those patients who require a bone marrow biopsy and whether the pathogenesis of IA involves a hyper-responsive mast cell compartment. Methods We prospectively enrolled patients with IA (≥3 episodes/yr) and who then underwent a medical evaluation that included a serum tryptase determination, allele-specific quantitative polymerase chain reaction (ASqPCR) for KIT D816V and a bone marrow examination. Mast cells were cultured from peripheral blood CD34+ cells and examined for releasibility following FcεRI aggregation. Results Clonal mast cell disease was diagnosed in 14% of patients referred with IA. ASqPCR for the KIT D816V mutation was a useful adjunct in helping identify those with systemic mastocytosis (SM) but not monoclonal mast cell activation syndrome (MMAS). A modified overall clonal prediction model was developed using clinical findings, a serum tryptase determination and ASqPCR. There was no evidence of a hyper-responsive mast cell phenotype in patients with IA. Conclusion Patients with clonal mast cell disease may present as idiopathic anaphylaxis. Distinct clinical and laboratory features may be used to select those patients more likely to have an underlying clonal mast cell disorder (MMAS or SM) and thus candidates for a bone marrow biopsy.
Aim: Children with cutaneous or systemic mastocytosis may experience severe manifestations of mast cell mediator release including anaphylaxis. The perceived risk for adverse vaccine reactions ...creates concern among parents and pediatricians regarding modification of the routine vaccine schedule for safety. Materials and Methods: Using the National Institutes of Health (NIH) Biomedical Translational Research Information System and Clinical Research Information System, we conducted a retrospective chart review of 94 children less than or equal to18 years of age, evaluated at NIH with mastocytosis. Based on the recommended childhood immunization schedule, we estimated that these 94 patients received approximately 2,136 vaccinations. Post vaccination reactions were determined as expected or unexpected according to the centers for disease control (CDC) parameters for vaccine-associated events. Results: Eighty-four patients (89.4%) had no reports of moderate-severe post-vaccination reactions. Eleven reactions after vaccination were reported in 10 of 94 patients (10.6%), of which four patients had unexpected reactions (4.3%). Unexpected reactions included facial swelling, flushing and exacerbation of skin lesions which are not reported as possible vaccine reactions by the CDC. One patient was treated for anaphylaxis 2 hours post-varicella vaccine administration. Five patients with a history of anaphylaxis and a mean tryptase level of 115 ng/mL did not report vaccine-induced reactions. Conclusion: Children with mastocytosis in this study did not experience a higher rate of adverse vaccine reactions compared to the general population. Anaphylaxis to other causes was not a risk factor for an untoward vaccine response. In patients that experience a severe post-vaccination reaction such as anaphylaxis, a modified schedule with single vaccine administration is a safer approach. Keywords: Pediatrics, mastocytosis, vaccines
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Summary
The diagnostic criteria for paediatric mastocytosis are largely based on adult studies and bone marrow findings are not well described in children. We evaluated use of the World Health ...Organization (WHO) criteria for the diagnosis of systemic disease in paediatric mastocytosis. In addition, we identified unique clinico‐histopathological features within the biopsies. One hundred and thirteen children with paediatric mastocytosis were evaluated at the National Institutes of Health between 1986 and 2013. Complete bone marrow evaluations were performed in 50 cases. Seven children had repeat procedures. Bone marrows were analysed by histopathology, flow cytometry and for KIT D816V. Bone marrow biopsies displayed mild atypical haematopoietic maturation, increased haematogones and hypocellularity in a sub‐set of patients with urticaria pigmentosa, diffuse cutaneous mastocytosis and indolent systemic mastocytosis. Hypocellularity was most pronounced in those with urticaria pigmentosa. Haematogones were highest, on average, in patients with diffuse cutaneous mastocytosis or mastocytomas. There was no evidence of peripheral blood cytopenias, myelodysplastic syndrome, myeloproliferative neoplasm or leukaemia within this cohort. The WHO criteria are applicable for the diagnosis of systemic mastocytosis in paediatrics. Although unsuspected bone marrow findings typically seen in myeloproliferative disorders are frequent in paediatric mastocytosis, patients within this study remained clinically stable without progression to a more aggressive variant.
Central venous catheters (CVCs), placed in the superior vena cava (SVC) for hemodialysis or chemotherapy, are routinely filled while not in use with heparin, an anticoagulant, to maintain patency and ...prevent thrombus formation at the catheter tip. The heparin-locking procedure, however, places the patient at risk for systemic bleeding, as heparin is known to leak from the catheter into the blood stream. We provide evidence from detailed in vitro experiments that shows the driving mechanism behind heparin leakage to be convective–diffusive transport due to the pulsatile flow surrounding the catheter. This novel mechanism is supported by experimental planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV) measurements of flow velocity and heparin transport from a CVC placed inside a model SVC inside a pulsatile flow loop. The results predict an initial, fast (<10 s), convection-dominated phase that rapidly depletes the concentration of heparin in the near-tip region, the region of the catheter with side holes. This is followed by a slow, diffusion-limited phase inside the catheter lumen, where the concentration is still high, that is insufficient at replenishing the lost heparin concentration in the near-tip region. The results presented here, which are consistent with previous in vivo estimates of 24 hour leakage rates, predict that the concentration of heparin in the near-tip region is essentially zero for the majority of the interdialytic phase, rendering the heparin locking procedure ineffective.
Methods Using the NIH Biomedical Translational Research Information System, we conducted a retrospective chart review of 115 children, evaluated at NIH with the diagnosis mastocytosis between ...1996-2014.
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