Identification of a novel KMT2A/GIMAP8 gene fusion in a pediatric patient with acute undifferentiated leukemia.

Acute undifferentiated leukemia (AUL) is a very rare hematologic neoplasm that expresses no markers specific for either myeloid or lymphoid lineages. While commonly observed in several acute leukemias, KMT2A rearrangements in AUL have been rarely reported in the literature. We report the third case to our knowledge of AUL harboring a KMT2A rearrangement. Furthermore, the KMT2A/GIMAP8 gene fusion identified in this case represents a novel KMT2A rearrangement.

Immune dysregulation and multisystem inflammatory syndrome in children (MIS-C) in individuals with haploinsufficiency of SOCS1.

BACKGROUND: We studied 2 unrelated patients with immune thrombocytopenia and autoimmune hemolytic anemia in the setting of acute infections. One patient developed multisystem inflammatory syndrome in children in the setting of a severe acute respiratory syndrome coronavirus 2 infection. OBJECTIVES: We sought to identify the mechanisms underlying the development of infection-driven autoimmune cytopenias. METHODS: Whole-exome sequencing was performed on both patients, and the impact of the identified variants was validated by functional assays using the patients' PBMCs. RESULTS: Each patient was found to have a unique heterozygous truncation variant in suppressor of cytokine signaling 1 (SOCS1). SOCS1 is an essential negative regulator of type I and type II IFN signaling. The patients' PBMCs showed increased levels of signal transducer and activator of transcription 1 phosphorylation and a transcriptional signature characterized by increased expression of type I and type II IFN-stimulated genes and proapoptotic genes. The enhanced IFN signature exhibited by the patients' unstimulated PBMCs parallels the hyperinflammatory state associated with multisystem inflammatory syndrome in children, suggesting the contributions of SOCS1 in regulating the inflammatory response characteristic of multisystem inflammatory syndrome in children. CONCLUSIONS: Heterozygous loss-of-function SOCS1 mutations are associated with enhanced IFN signaling and increased immune cell activation, thereby predisposing to infection-associated autoimmune cytopenias.

Extramedullary Myeloid Sarcoma with Symptoms of Acute Pancreatitis Mimicking Pancreatic Carcinoma.

Extramedullary myeloid sarcomas are extramedullary tumors of immature myeloid cells, often associated with acute myeloid leukemia (AML), chronic myeloid leukemia (CML), or other myeloproliferative diseases. They are usually found in connective/soft tissues, skin, breast and gastrointestinal system. Pancreas is an uncommon site to be involved. We present a case of pancreatic myeloid sarcoma presenting with symptoms of acute pancreatitis including epigastric pain associated with nausea and vomiting, with imaging findings (abdominal CT) suggestive of pancreatic carcinoma, both presenting as hypoattenuating mass. It is important to consider myeloid sarcoma as a differential for pancreatic mass, especially given the history of AML as in our patient, which would lead to timely diagnosis and initiation of chemotherapy.

Immune thrombocytopenia.

Immune thrombocytopenia (ITP) in children is a relatively uncommon and generally benign condition presenting as abrupt onset of bruising, petechiae and thrombocytopenia in an otherwise healthy child due to production of anti-platelet autoantibodies. Diagnosis is largely clinical and laboratory investigation should be kept to a minimum. Indications for treatment have not been standardized and include bleeding, parental anxiety and quality of life. Multiple treatments are available that have been proven to increase the platelet count; the most commonly employed include IVIG, steroids and WinRho (anti-D). Intracranial hemorrhage is the most serious potential complication but is extremely rare and splenectomy is reserved for chronically symptomatic patients who have not responded to other modalities. Identification of molecular targets may be a promising avenue for future research.

Recombinant human hyaluronidase-enabled subcutaneous pediatric rehydration.

OBJECTIVES: The Increased Flow Utilizing Subcutaneously-Enabled (INFUSE)-Pediatric Rehydration Study was designed to assess efficacy, safety, and clinical utility of recombinant human hyaluronidase (rHuPH20)-facilitated subcutaneous rehydration in children 2 months to 10 years of age. METHODS: Patients with mild/moderate dehydration requiring parenteral treatment in US emergency departments were eligible for this phase IV, multicenter, single-arm study. They received subcutaneous injection of 1 mL rHuPH20 (150 U), followed by subcutaneous infusion of 20 mL/kg isotonic fluid over the first hour. Subcutaneous rehydration was continued as needed for up to 72 hours. Rehydration was deemed successful if it was attributed by the investigator primarily to subcutaneous fluid infusion and the child was discharged without requiring an alternative method of rehydration. RESULTS: Efficacy was evaluated in 51 patients (mean age: 1.9 years; mean weight: 11.2 kg). Initial subcutaneous catheter placement was achieved with 1 attempt for 46/51 (90.2%) of patients. Rehydration was successful for 43/51 (84.3%) of patients. Five patients (9.8%) were hospitalized but deemed to be rehydrated primarily through subcutaneous therapy, for a total of 48/51 (94.1%) of patients. No treatment-related systemic adverse events were reported, but 1 serious adverse event occurred (cellulitis at infusion site). Investigators found the procedure easy to perform for 96% of patients (49/51 patients), and 90% of parents (43/48 parents) were satisfied or very satisfied. CONCLUSIONS: rHuPH20-facilitated subcutaneous hydration seems to be safe and effective for young children with mild/moderate dehydration. Subcutaneous access is achieved easily, and the procedure is well accepted by clinicians and parents.