Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is an aggressive life-threatening disease that consists of uncontrolled activated lymphocytes and macrophages that secrete excessive cytokines. Symptoms and laboratory findings of HLH include prolonged fever, cytopenia, hepatosplenomegaly, liver dysfunction, hypertriglyceridemia, hyperferritinemia, increased soluble interleukin-2 receptor, low fibrinogen, and neurological problems. HLH has two forms: primary (familial autosomal recessive) or secondary (related to infections, malignancy, autoimmune and metabolic disorders, transplantations, chimeric antigen receptor T-cell therapies, etc.) form. As underlying conditions in HLH varied, clinical findings are nonspecific and disease diagnosis is challenging. Furthermore, patients diagnosed with primary HLH can have a secondary triggering agent, such as infection. Thus, there is no clear-cut distinction between these two forms. Abnormal immune response and a low number or absence of natural killer cells and cytotoxic T-lymphocytes are hallmarks of HLH. Despite the early and aggressive treatment, HLH is a deadly disease. Urgent immunosuppressive therapy is necessary to control hyperinflammation. Hematopoietic stem cell transplantation is a curative treatment in familial forms. Targeted therapy with emapalumab was also recently reported to be effective.

Effect of platelet count and platelet transfusion on fever duration in patients with febrile neutropenia.

Platelets play a role in hemostasis, thrombosis, and vascular integrity. They also play a major role in the development of inflammation and the activation of immune responses. They have phagocytic activity, stimulate the secretion of immune modulators, and activate other immune cells, which results in platelet-neutrophil aggregation, platelet-induced neutrophil degranulation, and the formation of neutrophil extracellular traps. Data on 124 febrile neutropenia attacks were retrospectively examined. Patients' age, sex, diagnosis, and relapse history were obtained. The complete blood count levels on the first and last febrile day of the febrile neutropenia attacks, duration of fever, and number, type, and timing of thrombocyte suspension transfusions were recorded. The patients were divided into three groups according to the day of fever when the platelet suspension was administered (1 day, 2-3 days, and >3 days); the duration of fever was compared between the three groups. The fever duration of those who were transfused with platelet suspension on the first day of fever was found to be significantly shorter (p = 0.03 and p < 0.001, respectively). When treating a patient with febrile neutropenia, if thrombocyte suspension transfusion is indicated, transfusing thrombocytes in the first days of fever shortens the fever duration and improves the prognosis of febrile neutropenia attack, supporting the hypothesis that not only neutrophils but also platelets may play a role in fighting against microorganisms.

Clinical course of pediatric large vascular anomalies located in the extremities.

OBJECTIVE: Difficulties encountered in the diagnosis and treatment of vascular anomalies located in the extremities of the children. The most common vascular lesions are hemangiomas and venous malformations. The complex malformations, such as, Klippel-Trenaunay Syndrome are much less commonly encountered lesions. Treatment of vascular malformations are variable based on the etiology of the lesion and clinical presentation. In this study, we aimed to share our experience on the clinical features of vascular lesions in the extremities of the children. MATERIAL AND METHODS: The demographic, clinical and prognostic features of 330 children with vascular anomalies followed at IUC, Cerrahpasa Medical Faculty, Department of Pediatric Hematology and Oncology were retrospectively reviewed. Fifty-one patients with lesions >5 cm in diameter were included into the study. The diagnosis, age, sex, history of prematurity, lesion type and location, imaging and biopsy findings, complications, details of treatment, and follow-up were evaluated. RESULTS: Twenty-nine (57%) of patients were female and 22 (43%) were male. The female to male ratio was 1.3:1. The median age at admission was 15 months (10 days-180 months). Eight patients (16%) had a history of premature birth. Thirty-one patients (61%) had lesions since birth, eight lesions (8%) appeared in the first month of life and 6 (12%) occurred after 1 year of age. Sixteen of the patients (31%) had hemangioma, 11 (22%) had lymphangioma, 19 (37%) had venous malformation and 5 (10%) were diagnosed as Klippel Trenaunay Syndrome. The lesions were in the upper extremity in 21 patients (41%), in the lower extremity in 27 patients (53%), and both lower and upper extremities were affected in 3 patients (6%). Of all patients, six had intramuscular and two had intraarticular lesions. The diagnosis was made on clinical grounds in most of the cases. In 22 children Magnetic Resonance Imaging was performed for differential diagnosis and to demonstrate the infrastructure of the lesion and the extent of local infiltration. Histopathologic examination by biopsy was done in four patients. Complications developed in 19 patients as follows: Disseminated intravascular coagulation in 6, bleeding in 4, thrombosis in 3, and soft tissue infection in 6. Twenty-one patients were not given any treatment. Medical treatments were propranolol in 14 patients, sirolimus in 4 patients, propranolol and sirolimus in 5 patients. Intralesional bleomycin injection was performed in 3 children. CONCLUSION: The diagnosis, classification and treatment of extremity located vascular malformations in children are complex. Treatment strategy should be defined as in accordance with a combination of the type of the vascular malformation, the age of the patient and the clinical picture.