Skin Lesions as a Presenting Feature of Dimorphic T-Lymphoblastic Leukemia in an Adolescent Male.

Cutaneous involvement is rare in acute lymphoblastic leukemia/lymphoma, particularly within the T-cell lineage. Review of the literature for cutaneous involvement in T-cell lymphoblastic lymphoma/leukemia identifies mostly case reports, with the majority of cases involving adults. We describe an adolescent male presenting with cervical lymphadenopathy and skin lesions leading to a diagnosis of early T-cell precursor lymphoblastic leukemia. Unique to this case is the age of the patient, presence of a dimorphic blast population, and the skin lesions preceding other signs of disease by at least 1 month.

An Outbred Guinea Pig Disease Model for Lassa Fever Using a Host-Adapted Clade III Nigerian Lassa Virus.

Nigeria experiences annual outbreaks of Lassa fever (LF) with high case numbers. At least three clades of Lassa virus (LASV) have been documented in Nigeria, though recent outbreaks are most often associated with clade II or clade III viruses. Using a recently isolated clade III LASV from a case of LF in Nigeria in 2018, we developed and characterized a guinea pig adapted virus capable of causing lethal disease in commercially available Hartley guinea pigs. Uniform lethality was observed after four passages of the virus and was associated with only two dominant genomic changes. The adapted virus was highly virulent with a median lethal dose of 10 median tissue culture infectious doses. Disease was characterized by several hallmarks of LF in similar models including high fever, thrombocytopenia, coagulation disorders, and increased inflammatory immune mediators. High viral loads were noted in all solid organ specimens analyzed. Histological abnormalities were most striking in the lungs and livers of terminal animals and included interstitial inflammation, edema, and steatosis. Overall, this model represents a convenient small animal model for a clade III Nigeria LASV with which evaluation of specific prophylactic vaccines and medical countermeasures can be conducted.

Babesia microti in a Canadian blood donor and lookback in a red blood cell recipient.

BACKGROUND AND OBJECTIVES: We describe the third documented case of autochthonous human babesiosis in Canada and the second in a Canadian blood donor. MATERIALS AND METHODS: Multiple laboratory investigations were carried out on the donor and the immunocompromised recipient of an associated, potentially infectious red blood cell product. RESULTS: The donor had not travelled except for outdoor exposure in south-eastern Manitoba, followed by illness and hospital admission. The donor had a notable parasitaemia, positive for Babesia microti using whole blood nucleic acid testing (NAT). The recipient was negative for B. microti by both serology and NAT. CONCLUSION: There was no evidence of transfusion-transmitted babesiosis.

Acute Myeloid Leukemia Presenting as a Posterior Fossa Tumor.

Extramedullary leukemia in pediatric acute myeloid leukemia can manifest as a myeloid sarcoma (MS), also known as granulocytic sarcoma or chloroma, in a variety of sites, or as leukemic blasts in the cerebrospinal fluid. Isolated MS of the central nervous system is rare. We report a case of acute myeloid leukemia with central nervous system-MS presenting as a posterior fossa mass mimicking a primary intracranial tumor.

Precursor B-Cell Acute Lymphoblastic Leukemia With MYC and BCL2 Rearrangements Presenting as Extensive Extranodal Disease in an Adolescent.

Combined rearrangements of MYC and BCL2 are rare in precursor B-cell acute lymphoblastic leukemia (B-ALL). A 14-year-old boy presented with swelling of the knee and face. Imaging revealed diffuse infiltration of lacrimal glands, parotid glands along with the extensive epidural disease. Morphology and immunophenotype of knee joint aspirate were consistent with precursor B-ALL. Fluorescent in situ hybridization identified rearrangements of MYC and BCL2 genes. The disease was refractory to intensive treatment. The patient died of progressive disease. Precursor B-ALL with combined MYC and BCL2 rearrangements is rare, characterized by an aggressive clinical course, and has an inadequate response to standard therapeutic approaches.

Epidural Spinal Mass as the Presenting Feature of B-Acute Lymphoblastic Leukemia in a Young Child.

An isolated epidural mass is a rare presentation of childhood B-acute lymphoblastic leukemia with an estimated incidence of 0.4%. Of the cases reported in the literature, the majority involve adults presenting with spinal cord compression and/or systemic evidence of disease. We describe a young child presenting with pain leading to a refusal to weight-bear secondary to a sacral epidural mass. A biopsy of the sacral lesion confirmed the diagnosis of B-acute lymphoblastic leukemia. Unique to this case is the young age of the child and the lack of spinal cord compression.

Multifocal brain involvement in a patient with hairy cell leukemia successfully treated with rituximab and cladribine.

Brain involvement, although rare, can occur in HCL.The combination of cladribine and rituximab is a highly effective treatment of HCL with brain involvement.

Pentraxin 3 deletion aggravates allergic inflammation through a TH17-dominant phenotype and enhanced CD4 T-cell survival.

BACKGROUND: Pentraxin 3 (PTX3) is a multifunctional molecule that plays a nonredundant role at the crossroads between pathogen clearance, innate immune system, matrix deposition, female fertility, and vascular biology. It is produced at sites of infection and inflammation by both structural and inflammatory cells. However, its role in allergen-induced inflammation remains to be tested. OBJECTIVE: We sought to determine the effect of Ptx3 deletion on ovalbumin (OVA)-induced allergic inflammation in a murine model of asthma. METHODS: Bronchoalveolar lavage fluid was collected from patients with severe asthma and healthy subjects, and the level of PTX3 was determined by using ELISA. Ptx3+/+ and Ptx3-/- mice were sensitized and challenged with OVA and bronchoalveolar lavage fluid, and the lungs were collected for assessing inflammation. Lung tissue inflammation and mucus production were assessed by means of flow cytometry and hematoxylin and eosin and periodic acid-Schiff staining, respectively. flexiVent was used to determine airway resistance to methacholine in these mice. RESULTS: Here we report that mice with severe asthma and OVA-sensitized/challenged mice had increased PTX3 levels in the lungs compared with healthy control mice. Mice lacking PTX3 have exaggerated neutrophilic/eosinophilic lung inflammation, mucus production, and airway hyperresponsiveness in an experimental model of OVA-induced asthma. Furthermore, OVA-exposed lung Ptx3-/- CD4 T cells exhibit an increased production of IL-17A, an effect that is accompanied by an increased signal transducer and activator of transcription 3 phosphorylation, reduced IL-2 production, and enhanced activation and survival. Also, we observed an increase in numbers of IL-6- and IL-23-producing dendritic cells in OVA-exposed Ptx3-/- mice compared with those in wild-type control mice. CONCLUSION: Altogether, PTX3 deficiency results in augmented airway hyperresponsiveness, mucus production, and IL-17A-dominant pulmonary inflammation, suggesting a regulatory role of PTX3 in the development of allergic inflammation.

Evidence that stainable bone marrow iron following parenteral iron therapy does not correlate with serum iron studies and may not represent readily available storage iron.

We recently reported that parenteral iron therapy is associated with a characteristic pattern of iron staining on bone marrow aspirate smears. We now present clinical information from 6 patients who received parenteral iron and, at one or more points in follow-up, were found to have low or borderline low serum ferritin levels and/or serum iron levels, even though marrow aspirate smears revealed abundant stainable iron in the pattern characteristic of prior parenteral iron therapy. We conclude that stainable iron seen in this pattern does not correlate with serum iron studies and may not represent functionally available storage iron. This pattern of iron staining should not be used as evidence to withhold further iron therapy in patients who otherwise continue to have features of iron deficiency anemia.