Hemophagocytic Lymphohistiocytosis (Hlh)

The hemophagocytic lymphohistiocytosis (HLH) is a rare disease in which occurs in infants and young children to immunological disorders. In many patients an immune deficiency underlies although in some the underlying disorder is not known. It can show lymphadenopathy and hepatosplenomegaly, fever, and neurological abnormalities. Diagnosis is based on specific clinical criteria and (genetic) tests. Treatment usually consists of chemotherapy and in refractory cases or in patients with a genetic cause in the hematopoietic stem cell transplantation.

The hemophagocytic lymphohistiocytosis rarely occurs. Especially infants <18 months have affected. There is a defect in the targeted defense function and the inhibitory control of natural killer cells and cytotoxic T cells, which leads to excessive production of cytokines and an accumulation of activated T cells and macrophages in different organs. Bone marrow and / or spleen cells can attack erythrocytes, leukocytes and / or platelets.

The hemophagocytic lymphohistiocytosis (HLH) is a rare disease in which occurs in infants and young children to immunological disorders. In many patients an immune deficiency underlies although in some the underlying disorder is not known. It can show lymphadenopathy and hepatosplenomegaly, fever, and neurological abnormalities. Diagnosis is based on specific clinical criteria and (genetic) tests. Treatment usually consists of chemotherapy and in refractory cases or in patients with a genetic cause in the hematopoietic stem cell transplantation. The hemophagocytic lymphohistiocytosis rarely occurs. Especially infants <18 months have affected. There is a defect in the targeted defense function and the inhibitory control of natural killer cells and cytotoxic T cells, which leads to excessive production of cytokines and an accumulation of activated T cells and macrophages in different organs. Bone marrow and / or spleen cells can attack erythrocytes, leukocytes and / or platelets. The disposition of the haemophagocytic lymphohistiocytosis is: Family (primary) Acquired (secondary) The diagnostic hemophagocytic lymphohistiocytosis is made when at least 5 of the following criteria are fulfilled or there is a mutation in a known HLH-associated gene. Acquired hemophagocytic lymphohistiocytosis may concomitantly with other diseases of the immune system (eg. As leukemias, lymphomas, SLE, rheumatoid arthritis, polyarthritis nodosa, sarcoidosis, progressive systemic sclerosis, Sjogren's syndrome, Kawasaki disease) and in recipients of kidney or liver transplants occur. The emergence of acquired haemophagocytic lymphohistiocytosis can possibly be attributed to this disease itself or to the immunosuppressive therapy and infections. In both forms of genetic changes, clinic and disease appear to be similar. Symptoms and signs often occur fever, hepatomegaly, splenomegaly, skin rash, swollen lymph nodes and neurological abnormalities (eg. As seizures, retinal hemorrhage, ataxia, impaired consciousness or coma) on. Bone lesions may occur, the clinical picture can mimic a child abuse. Diagnosis Clinical and test criteria, the diagnosis hemophagocytic lymphohistiocytosis can be made when a mutation is present in a responsible for the disease gene or if 8 diagnostic criteria are met at least 5: fever (maximum temperature of> 38.5 ° C for> 7 days) splenomegaly ( spleen palpable> 3 cm below the costal arch) cytopenia with> 2 cell lines (hemoglobin <9 g / dl, neutrophil count <100 / ul, platelet count <100,000 / ?.) hypertriglyceridemia (fasting Triglyzeridwert> 2.0 mmol / l or> 3 standard deviation [SD] more than the age norm value) or hypofibrinogenemia (fibrinogen value <1.5 g / l or> 3 SD below the age norm value) Hemophagocytosis (in biopsy samples from bone marrow, spleen or lymph nodes) Low or absent activity of natural killer cells Serum ferritin> 500 ug / l Increased levels of soluble IL-2 receptor (CD25) (> 2400 IU / ml or very high for the age value) Clinical Calculator: Absolute neutrophil count, since some of these tests may not be available everywhere, and the hemophagocytic lymphohistiocytosis rare, patients are usually referred for evaluation to specialized centers. Treatment chemotherapy, immunosuppression, followed by hematopoietic stem cell transplantation is suspected the disease, treatment should be initiated, although not all diagnostic criteria are met. Patients are usually treated by a pediatric hematologist and a reference center for hemophagocytic lymphohistiocytosis. The treatment depends on factors such as family history of HLH, concomitant infections and proven immune defects.

Health Life Media Team

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