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Query: UMLS:C0019621 (Langerhans cell histiocytosis)
 3,250 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hemophagocytic lymphohistiocytosis, terminology that designates a syndrome that may be familial or sporadic, with or without an associated viral infection, is presented as the prototype of a hemophagocytic syndrome, a condition in which there is uncontrolled activation of the cellular immune system. Diagnostic criteria include idiopathic fever, splenomegaly, cytopenias, hypertriglyceridemia, hypofibrinogenemia, and the presence of hemophagocytosis. The surgical and autopsy pathology features infiltrates composed of lymphocytes and ordinary, but activated, histiocytes and hemophagocytosis. The chronic hepatitis-like hepatic lesion is noted to be characteristic, if not unique, in this age group and setting. Current concepts of pathophysiology focus on the role of cytokines, particularly interleukin (IL)-1, IL-2, soluble IL-2 receptor, plasminogen activator, and prostaglandins. The clinicopathologic features of the syndrome can be accounted for by the uncontrolled and unopposed production and release of these mediators. Nosology places hemophagocytic lymphohistiocytosis in the position of the most important of the "benign" histiocytosis syndromes that involve ordinary histiocytes of the mononuclear phagocytic system in contrast to Langerhans cell histiocytosis (histiocytosis X) in which pathological dendritic histiocytes are operative. Features that distinguish hemophagocytic lymphohistiocytosis from other disorders, such as malignant histiocytosis, X-linked lymphoproliferative disorder, congenital immunodeficiency states, the accelerated phase of Chediak-Higashi syndrome, and cytophagic histiocytic panniculitis, which may be associated with a hemophagocytic syndrome, are presented.
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PMID:Hemophagocytic lymphohistiocytosis: a hemophagocytic syndrome. 156 89

The histiocytoses comprise a rare and incompletely understood group of diseases that are characterized by an abnormal proliferation of histiocytes, mononuclear phagocytic, and antigen-presenting cells belonging to the reticuloendothelial system. The two major types of histiocytoses, which often present during infancy and require significant medical attention, are Langerhans cell histiocytosis and primary hemophagocytic lymphohistiocytosis. Their clinical manifestations frequently overlap, complicating their distinction, but a prompt and accurate diagnosis is essential to deliver the optimal treatment and maximize the chances for a favorable outcome. For Langerhans cell histiocytosis, careful risk stratification is critical for the appropriate administration of therapy. Patients with good prognostic factors may need only observation as their disease spontaneously regresses or minimal intervention. Poor prognostic factors mandate more intensive treatment. Patients with primary hemophagocytic lymphohistiocytosis require chemotherapeutic induction of their disease into a state of remission followed by stem cell transplantation, which currently offers the only known cure. Improvements on current therapies for the histiocytoses will depend on continued advances in the understanding of these enigmatic diseases.
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PMID:The histiocytoses of infancy. 1047 45

Langerhans cell histiocytosis (LCH) with subsequent viral-associated hemophagocytic syndrome (VAHS) or secondary hemophagocytic lymphohistiocytosis (HLH) is extremely rare. A 15-month-old girl with disseminated LCH experienced three episodes of VAHS during maintenance therapy. Viral infection, with influenza A, herpes simplex, and adenovirus, respectively, was documented at each episode. She recovered each time after interruption of maintenance therapy. The occurrence of fever and pancytopenia in patients with chemotherapy-treated LCH can be associated with VAHS and not with relapsing LCH.
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PMID:Recurrent viral associated hemophagocytic syndrome in a child with Langerhans cell histiocytosis. 1059 73

The histiocytoses are rare disorders of antigen-processing phagocytic or antigen-presenting cells. Allogeneic bone marrow transplantation (BMT) can be curative of these disorders. We report a series of five children with Langerhans cell histiocytosis (n=2) or hemophagocytic lymphohistiocytosis (n=3), who received allogeneic BMT with a total body irradiation (TBI)-containing regimen (TBI, cytarabine, and cyclophosphamide) at our institution between 1995 and 2000. One of these patients received busulfan, cyclophosphamide, and etoposide for the first of two BMTs. All grafts except one (a matched sibling-donor graft) were T-cell-depleted grafts from unrelated donors. All received cyclosporine graft-versus-host disease (GvHD) prophylaxis; the recipient of the matched sibling graft also received methotrexate. Three patients engrafted at a median of 24 days after transplantation. The patient who did not receive TBI experienced primary graft failure and recurrent disease. After the TBI-containing conditioning regimen was given, a second transplant engrafted on day +17. One patient with concurrent myelodysplastic syndrome died of toxicity on day +33 without evidence of engraftment. No acute or chronic GvHD was observed. Four patients survive disease-free, a median of 63 months after transplantation, all with Lansky performance scores of 100. We conclude that a conditioning regimen containing TBI but not etoposide is effective in allogeneic BMT for children with histiocytic diseases.
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PMID:Allogeneic bone marrow transplantation for children with histiocytic disorders: use of TBI and omission of etoposide in the conditioning regimen. 1277 48

Hemophagocytic lymphohistiocytosis (HLH) and Langerhans cell histiocytosis (LCH) are members of a group of rare heterogenous disorders, the histiocytoses, characterized by uncontrolled accumulation of pleomorphic infiltrates of leukocytes. The etiology of these diseases is mainly unknown. CD45 is a hemopoietic cell specific tyrosine phosphatase essential for antigen receptor mediated signaling in lymphocytes and different patterns of CD45 splicing are associated with distinct functions. Recently a polymorphism (C77G) in exon 4 of CD45 causing abnormal CD45 splicing and a point mutation affecting CD45 dimerization were implicated in multiple sclerosis in humans and lymphoproliferation and autoimmunity in mice respectively. Here we show that two patients with HLH exhibited abnormal CD45 splicing caused by the C77G variant allele, while a further 21 HLH patients have normal CD45. We have also examined 62 LCH patients and found three to have the C77G mutation. Peripheral blood thymus-derived (T) CD8(+) cells from normal individuals carrying the C77G mutation show a significant decrease in the proportion of cells expressing L-selectin and increased frequency of cells with LFA-1(hi) expression. It remains to be established whether C77G is a contributing factor in these histiocytic disorders.
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PMID:Abnormal cell surface antigen expression in individuals with variant CD45 splicing and histiocytosis. 1463 Sep 80

Since the first description of infection-associated hemophagocytosis (IAHS), the list of precipitating infectious agents causing hemophagocytic syndrome has grown. A lymphohistiocytic proliferation with hemophagocytosis may develop as a result of macrophage activation, viral or bacterial infection, parasitic infestations, or malignancy. The authors report on a 3-year-old boy with Langerhans cell histiocytosis (LCH), who developed IAHS during malaria infection. Hemophagocytic syndromes may complicate the course of LCH and cause diagnostics problems. Malaria is one of many infections that can precipitate secondary hemophagocytic lymphohistiocytosis.
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PMID:Secondary hemophagocytic lymphohistiocytosis induced by malaria infection in a child with Langerhans cell histiocytosis. 1520 66

We report a case of juvenile xanthogranuloma (JXG) having progressive pancytopenia for 6 months until the proliferating skin lesions. A 2-month-old infant presented recurrent fever, anemia, and hepatosplenomegaly mimicking hemophagocytic lymphohistiocytosis (HLH) or juvenile myelomonocytic leukemia (JMML). At 8 months of age, the biopsy of a growing papule on the elbow made the diagnosis. Bone marrow (BM) specimens showed clustering foamy cells including hemophagocytosis by histiocytes. Treatment with etoposide followed by vinblastine plus prednisolone (PSL) therapy improved the disease. Although JXG is a benign non-Langerhans cell histiocytosis, the multisystem-visceral form should be considered as a potential aggressive disease when associated with BM failure in early infancy.
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PMID:Prolonged severe pancytopenia preceding the cutaneous lesions of juvenile xanthogranuloma. 1604 46

The coincidence of T-cell acute lymphoblastic leukemia (T-ALL) and histiocytic disorders, including hemophagocytic lymphohistiocytosis (T-ALL/HLH) and Langerhans cell histiocytosis (T-ALL/LCH), is very seldom and is usually associated with a dismal prognosis. Retrospective statistical analysis of all T-ALL patients, who have been registered in the BFM-ALL trials from 1981 - 2001 and who have subsequently developed a LCH/HLH, in order to identify any common risk factors pre-disposing to the synchronous occurrence of both disorders. Six out of 971 T-ALL patients had either HLH or LCH ( approximately 0.03% of treated T-ALL/year). The mean age at diagnosis of T-ALL/HLH/LCH was significantly lower than in the remaining T-ALL group (4.05 +/- 0.59 vs 8.82 +/- 0.14 years; p = 0.000). The mean initial leukocyte count was higher than in the non-HLH/LCH group (270,700 +/- 60,677 microl(-1) vs 134,141 +/- 5,663 microl(-1); p = 0.074). No hemophagocytosis was seen in the initial bone marrow (BM) smears. Five of 6 patients obtained a good prednisone response (GPR) at day 8 in peripheral blood with <5% blasts at day 15 in BM and all cases were in complete remission (CR) at day 33. The mean time until development of the histiocytosis was 17.95 months (range 2.5 - 33 months). Four patients developed a HLH and 2 a LCH. All patients with HLH showed a multi-organ involvement, while the LCH patients had only local disease. Only the LCH patients survived, while all patients with HLH died. The authors recommend a close follow-up for at least 3 years after diagnosis in younger T-ALL patients with high initial leukocyte count.
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PMID:Histiocytosis following T-acute lymphoblastic leukemia: a BFM study. 1626 75

The histiocytic syndromes of childhood are disorders of the reticuloendothelial system with variable clinical manifestations. Included among them are Langerhans cell histiocytosis and hemophagocytic lymphohistiocytosis. This discussion will be restricted to these two disorders. Liver disease in these conditions is common. Langerhans cell histiocytosis is characterized by the abnormal clonal proliferation of the macrophage-derived Langerhans cell. Liver involvement at diagnosis has management and prognostic significance. In a subgroup of patients, sclerosing cholangitis develops, which may lead to end-stage liver disease requiring liver transplantation. Hemophagocytic lymphohistiocytosis is a disease of abnormally activated macrophages that can involve multiple organ systems, including the liver. Differentiation between this disorder and other causes of pediatric liver disease is critical, because treatment strategies include chemotherapy, immunosuppression, and frequently bone marrow transplantation.
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PMID:Liver involvement in childhood histiocytic syndromes. 1703 Dec 4

The histiocyte disorders are divided into the following 3 categories according to the specific lineage of the histiocytes involved and their biological behavior: the dendritic cell-related disorders, which include Langerhans cell histiocytosis and dermal dendrocyte disorders; the macrophage cell disorders, hemophagocytic lymphohistiocytosis being the main entity; and the malignant histiocyte disorders. We present a case of a 36-year-old woman who was referred to our hospital because of fever of unknown origin, lethargy, anemia, and impaired hepatic function. Following a thorough investigation, we diagnosed extensive histiocyte-mediated phagocytosis in many areas (skin, liver, bone marrow), without any identifiable cause. The disease was controlled by immunosuppressive therapy, and the patient remains in complete remission. This case supports the concept of idiopathic generalized histiocyte activation as a distinct entity; this putative disease entity produces massive phagocytosis, regardless of the type of histiocyte differentiation. Similar cases necessitate further study for classification and management.
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PMID:Primary adult-onset macrophage activation syndrome with multisystemic tissue phagocytosis. 1819 5


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