Histiocytoses

Improved outcome of refractory Langerhans cell histiocytosis in children with hematopoietic stem cell transplantation in Japan

Langerhans cell histiocytosis (LCH) that is refractory to conventional chemotherapy has a poor outcome. Hematopoietic stem cell transplantation (SCT) is a promising approach for refractory LCH because of its immunomodulatory effect. In this study, the outcomes of children with refractory LCH undergoing SCT in Japan were analyzed. Between November 1995 and March 2007, 15 children younger than 15 years (9 males, 6 females) with refractory LCH underwent SCT. The patients' median age at diagnosis was 8 months (range, 28 days to 28 months), and all had failed conventional chemotherapy. The median age at SCT was 23 months (range, 13-178 months). Nine had risk organ involvement at diagnosis, including liver (n=6), spleen (n=5), lung (n=5), and/or hematopoietic system (n=4). For SCT, a myeloablative regimen was used for 10 patients, and a reduced-intensity conditioning regimen (RIC) was used for five. The donor source varied among the patients, but allogeneic cord blood was primarily used (n=10). Subsequently, 11 of 15 patients have survived with no evidence of disease, with a 10-year overall survival (OS) rate (median+/-standard error) of 73.3+/-11.4%. The 10-year OS rate of nine patients with risk organ involvement at diagnosis was 55.6+/-16.6%, whereas six without risk organ involvement have all survived with no evidence of disease (P=0.07). These results indicate that SCT is promising as a salvage approach for children with refractory LCH.

Fetal and neonatal histiocytoses

PURPOSE

The histiocytoses are a group of disorders of the monophagocytic system having a variety of clinical and pathological findings. They occur less often during the perinatal period than later in life. Their biologic behavior, response to therapy, and histologic types are not the same.

METHODS

The study consisted of 221 fetuses and neonates collected from the literature and from personal files.

RESULTS

Langerhans' cell histiocytosis (LCH), the hemophagocytic lymphohistiocytoses (HLH), and juvenile xanthogranuloma (JXG), in order of rank, were the main histiocytoses occurring in the perinatal period. HLH accounted for the highest mortality (74%) followed by disseminated LCH (52%) and JXG (11%). All neonates with LCH and JXG limited to the skin and/or subcutaneous tissue survived with or without treatment.

CONCLUSIONS

This study suggests that there is an increased incidence of spontaneous regression of certain histiocytic lesions in neonates as compared to older individuals. Cutaneous forms JXG and LCH had the highest incidence of regression followed by infection associated HLH.

Les tumeurs osseuses rachidiennes chez l'enfant et l'adolescent

The occurrence of back pain in children and adolescents varies from 30 to 51% in the literature. Bone tumors can be responsible for back pain. This paper presents the more common spinal bone tumors in children and adolescents, and specifies their etiology, their natural history, and their treatment as well.

Allogeneic bone marrow transplantation for children with histiocytic disorders: use of TBI and omission of etoposide in the conditioning regimen

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.

Effect of chemotherapy and stem cell transplantation on T lymphocyte clones in familial haemophagocytic lymphohistiocytosis

Familial haemophagocytic lymphohistiocytosis (FHL) is a rare disorder in infancy, curative only by an allogeneic stem cell transplantation (SCT). We recently confirmed the clonal evidence of T cells in FHL. To confirm the effect of chemotherapy and SCT in FHL, the change of T-cell clones was analysed in two patients using inverse reverse transcription-polymerase chain reaction (RT-PCR) of the T-cell receptor variable region (TCR V) gene, followed by PCR for the junctional region (Jbeta-PCR), a single-strand conformation polymorphism (SSCP) and sequencing analysis at diagnosis, after chemotherapy and after SCT. A high frequency (> 15%) of alphabeta T-cell clones and a predominant bias (Jbeta1:Jbeta2, 85:15) for the Jbeta1 subgroup were observed in the two patients at diagnosis. In one patient, however, an inverted predominant bias (Jbeta1:Jbeta2, 9:91) for the Jbeta2 subgroup and oligoclonal expansion were observed at relapse after chemotherapy. In the other patient, correction of both restricted Jbeta cluster usage and variation of TCR were observed after chemotherapy and SCT. Using sequence analysis, the clonal T cells detected at diagnosis were found to be substituted at low frequency (< 0.75%) by several new clones after chemotherapy and SCT. These results indicate that any genetic defect could influence the regulation of the T-cell network, and normalization of both the variation in each Vbeta repertoire and the Jbeta1/Jbeta2 ratio is needed to achieve remission, and might support the rationale that the only acceptable curative therapy of FHL is allogeneic SCT.

Stem-cell transplantation for inherited immunodeficiency disorders

For patients with well-characterized, rapidly fatal, nonmalignant immunodeficiency disorders, such as SCID, the decision to proceed with allogeneic SCT is clear-cut. For patients with many other disorders, this decision can be extremely difficult. Disorders such as LAD or CGD have a variable natural history. Each patient must be considered individually, with the risk for SCT-related morbidity and mortality carefully weighed against that of the underlying disease. Significant advances during the past 10 years have made SCT a much safer procedure. Use of nonmyeloablative conditioning regimens as a means of reducing toxicity of high-dose chemotherapy and irradiation hold great promise. Highly immunosuppressive, nonchemotherapeutic agents that inhibit graft rejection or GVHD by blocking the critical costimulatory component of the T-cell receptor-antigen interaction are beginning to emerge and may be ideal for SCT of nonmalignant diseases. Therefore, the risk-benefit equation must be reassessed each year as the severity of patients' disorders is better defined and techniques of SCT improve.

Hemophagocytic syndrome: A misleading complication of visceral leishmaniasis in children--a series of 12 cases

OBJECTIVE

To describe the difficulties in diagnosing visceral leishmaniasis (VL) when revealed by hemophagocytic syndrome (HS) in young children.

DESIGN

Retrospective study of patients identified over a 17-year period in French pediatric units.

RESULTS

This series comprises 12 cases of VL that were either revealed (n = 11) or complicated (on starting treatment with antimony salts [n = 1]) by HS. Clinical manifestations were those of severe VL with sustained high fever and hepatosplenomegaly in children in very poor condition. Biological manifestations always included pancytopenia, marked hypofibrinogenemia and hypertriglyceridemia, hepatic cytolysis, and prominent hemophagocytosis on the bone marrow smear. These features led to transfer to a hematology unit. Ten children were very young (<38 months) at onset (and consequently at infection). Signs of autoimmunity (Coombs' test-positive erythrocytes, antinuclear factors, and various autoantibodies) were found in 4 cases and were probably secondary to polyclonal B cell activation. Serologic tests for Leishmania were negative at onset in 6 children, and no amastigotes were found on the first marrow smear in 8 of 12 cases despite extensive search. Seven patients had not visited foreign countries. All these factors explain the initial diagnostic confusion. Three cases were initially misdiagnosed as familial erythrophagocytic lymphohistiocytosis or infection-associated HS, and these patients were treated with etoposide (once for 5 months) to control the HS after failure of steroids. The diagnostic delay in these cases was 50, 74, and 134 days. When VL was finally diagnosed, amphotericin B monotherapy was effective in 4 cases. Eight patients were treated with antimony salts; 4 were cured, 3 required adjunctive treatment, and 1 worsened (HS) and was cured with steroids and liposomal amphotericin. Regardless of the type of therapy, all 12 children are presumed cured with a mean follow-up of 7 years (range: 6 months-16 years).

CONCLUSIONS

A diagnosis of VL should, therefore, be seriously considered in all young patients with HS exposed to visceralizing Leishmania sp in Southern Europe. Clinicians and cytopathologists must be aware of the association. Early diagnosis of VL will minimize unnecessary hospitalization and potentially harmful investigations and treatments.

[Reactive hemophagocytic syndrome in children]

Reactive haemophagocytic syndrome is characterized by activation and uncontrolled non-malignant proliferation of T lymphocytes and macrophages, leading to a cytokine overproduction, which accounts for the main biological signs. Children usually present with an acute febrile illness, fulminant pancytopenia and hepatosplenomegaly, posing a problem of differential diagnosis with severe sepsis. Hemopoietic cells are actively ingested by monocytes/macrophages in various organs, including lymph nodes, bone marrow, liver and spleen. This exarcerbation of the histiocytic system is currently classified among the reactional histiocytoses. It reflects an inappropriate host immune response. Most patients have a known underlying disease (hemopathy, lupus, systemic juvenile arthritis, HIV infection). In the few cases that occur in the apparent absence of any risk factors, investigations should be made to look for predisposing inherited diseases, such as familial lymphohistiocytosis or Purtilo's disease in boys. The treatment rests on immunosuppressive agents, followed by bone marrow transplantation, which can provide a definitive cure in genetic forms.

[Basedow's disease in an adolescent with histiocytosis X]

BACKGROUND

Immunological dysfunction is known to be present in Langerhans cell histiocytosis; some autoimmune diseases with autoantibodies associated with this condition have already been described. This immunological dysfunction could play a role in the Langerhans cell histiocytosis pathogenesis.

CASE REPORT

A 13 year-old boy presented a multifocal bone Langerhans cell histiocytosis associated with Graves' syndrome. This last condition was successfully treated with carbimazole while the focal lesions of histiocytosis did not require any treatment.

CONCLUSION

This unique association could be explained by the immunological dysfunction seen in Langerhans cell histiocytosis with secondary appearance of thyreo-stimulating antibodies.