Hematopoietic stem cell transplantation in severe congenital neutropenia

BACKGROUND

Severe congenital neutropenia (SCN) is an immunodeficiency characterized by disturbed myelopoiesis and an absolute neutrophil count (ANC) <0.5 × 10(9)/L. SCN is also a premalignant condition; a significant proportion of patients develop myelodysplastic syndrome or leukemia (MDS/L). Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment for SCN.

PROCEDURE

Since 2004, eight HSCT have been performed in seven patients at our center. The indications were transformation to MDS/L (n = 2), granulocyte colony-stimulating factor receptor (CSF3R) mutation(s) (n = 2), granulocyte colony-stimulating factor (G-CSF) resistance (n = 2), and at the patient's own request (n = 1).

RESULTS

The mean age at transplantation was 13 years (2.8-28 years) (mean follow-up 32 months, range 21-60). Three patients harbored ELANE mutations, three HAX1 mutations, and in one patient no causative mutation was identified. Two of the ELANE mutations were novel mutations. Three patients initially received myeloablative conditioning and four had reduced intensity conditioning (RIC). Three grafts were from HLA-identical siblings, three from matched unrelated donors and two were cord blood units. Engraftment occurred in all patients. Two of seven (29%) patients died; both had MDS/L and both were among the three that underwent myeloablative conditioning. One patient has chronic GVHD 2 years post-transplant.

CONCLUSIONS

The role of HSCT should be explored further in patients with SCN. In particular, the influence of the conditioning regime needs to be evaluated in a larger cohort of patients.

Central nervous system involvement in severe congenital neutropenia: neurological and neuropsychological abnormalities associated with specific HAX1 mutations

OBJECTIVES

Homozygous mutations in the HAX1 gene were recently identified in severe congenital neutropenia patients belonging to the original Kostmann family in northern Sweden. Our observations suggested that these patients also develop neurological and neuropsychological symptoms.

METHODS

Detailed clinical studies and mutation analyses were performed in the surviving patients belonging to the Kostmann kindred and in two patients not related to this family, along with studies of HAX1 splice variant expression in normal human tissues.

RESULTS

Five of six Kostmann family patients and one other patient from northern Sweden harboured homozygous HAX1 mutations (568C-->T, Q190X) and one carried a heterozygous ELA2 gene mutation. One Swedish patient of Kurdish extraction carried alternative homozygous HAX1 mutations (131G-->A, W44X). All the three patients with Q190X mutations who were alive and available for evaluation developed neurological disease with decreased cognitive function, and three of four patients who reached 10 years developed epilepsy. In contrast, the patients with the ELA2 and W44X HAX1 mutations, respectively, showed no obvious neurological abnormalities. Moreover, two alternative HAX1 splice variants were identified in normal human tissues, including the brain. Both transcripts contained exon 5, harbouring the Q190X mutation, whereas the 5' end of exon 2 containing the W44X mutation was spliced out from the second transcript.

CONCLUSIONS

We describe neurological and neuropsychological abnormalities for the first time in Kostmann disease patients. These central nervous system symptoms appear to be associated with specific HAX1 mutations.

Spectrum, and clinical and functional implications of UNC13D mutations in familial haemophagocytic lymphohistiocytosis

OBJECTIVE

Familial haemophagocytic lymphohistiocytosis (FHL) is a fatal disorder of immune dysregulation with defective cytotoxic lymphocyte function. Disease-causing mutations have been identified in the genes encoding perforin (PRF1), syntaxin-11 (STX11), and Munc13-4 (UNC13D). We screened for UNC13D mutations and studied clinical and functional implications of such mutations in a well defined patient cohort.

METHODS

Sequencing of UNC13D was performed in 38 FHL patients from 34 FHL families in which PRF1 and STX11 mutations had been excluded.

RESULTS

We identified six different mutations affecting altogether 9/38 individuals (24%) in 6/34 (18%) unrelated PRF1/STX11-negative families. Four novel mutations were revealed; two homozygous nonsense mutations (R83X and W382X), one splice mutation (exon 28), and one missense mutation (R928P). In addition, two known mutations were identified (R214X and a deletion resulting in a frame-shift starting at codon 782). There was considerable variation in the age at diagnosis, ranging from time of birth to 14 years (median 69 days). Three of nine patients (33%) developed central nervous system (CNS) symptoms. Natural killer (NK) cell activity was impaired in all four patients studied. Defective cytotoxic lymphocyte degranulation was evident in the two patients investigated, more pronounced in the patient with onset during infancy than in the patient with adolescent onset.

CONCLUSIONS

Biallelic UNC13D mutations were found in 18% of the PRF1/STX11-negative FHL families. Impairment of NK cell degranulation was less pronounced in a patient with adolescent onset. FHL should be considered not only in infants but also in adolescents, and possibly young adults, presenting with fever, splenomegaly, cytopenia, hyperferritinaemia, and/or CNS symptoms.

Genotype-phenotype study of familial haemophagocytic lymphohistiocytosis due to perforin mutations

BACKGROUND

PRF1 gene mutations are associated with familial haemophagocytic lymphohistiocytosis type 2 (FHL2). Genotype-phenotype analysis, previously hampered by limited numbers of patients, was for the first time performed by data pooling from five large centres worldwide.

PATIENTS AND METHODS

Members of the Histiocyte Society were asked to report cases of FHL2 on specific forms. Data were pooled in a common database and analysed.

RESULTS

The 124 patients had 63 different mutations (including 15 novel mutations): 11 nonsense, 10 frameshift, 38 missense and 4 in-frame deletions. Some mutations were found more commonly: 1122 G-->A (W374X), associated with Turkish origin, in 32 patients; 50delT (L17fsX22) associated with African/African American origin, in 21 patients; and 1090-91delCT (L364fsX), in 7 Japanese patients. Flow cytometry showed that perforin expression was absent in 40, reduced in 6 and normal in 4 patients. Patients presented at a median age of 3 months (quartiles: 2, 3 and 13 months), always with fever, splenomegaly and thrombocytopenia. NK activity was absent in 36 (51%), <or=2% in 18 (26%), 3-<or=5% in 10 (14%), >5% in 4 (6%), "reduced" in 2 (3%) (not reported, n = 54). Nonsense mutations were significantly associated with younger age at onset (p<0.001) and absent natural killer activity (p = 0.008).

CONCLUSION

PRF1 mutations are spread over the functional domains. Specific mutations are strongly associated with Turkish, African American and Japanese ethnic groups. Later onset and residual cytotoxic function are observed in patients with at least one missense mutation.

Assignment of the gene locus for severe congenital neutropenia to chromosome 1q22 in the original Kostmann family from Northern Sweden

Autosomal recessive severe congenital neutropenia (SCN) or Kostmann syndrome is characterised by reduced neutrophil counts and subsequent recurrent bacterial infections. The disease was originally described in a large consanguineous pedigree from Northern Sweden. A genome-wide autozygosity scan was initiated on samples from four individuals in the original pedigree using high density single nucleotide polymorphism (SNP) genotyping arrays in order to map the disease locus. Thirty candidate regions were identified and the ascertainment of samples from two additional patients confirmed a single haplotype with significant association to the disorder (p<0.01) on chromosome 1q22. One affected individual from the original Kostmann pedigree was confirmed as a phenocopy. The minimal haplotype shared by affected individuals spans a candidate region of 1.2 Mb, containing several potential candidate genes.

A journey of hope: lessons learned from studies on rare diseases and orphan drugs

Rare diseases are frequently life-threatening or chronically debilitating and the impact on the quality of life of affected patients and their family members is thus significant. However, drug development for these conditions has been limited by a lack of understanding of the underlying mechanisms of disease and the relative unavailability of subjects for clinical trials, as well as the prohibitive cost of investing in a novel pharmaceutical agent with poor market potential. Nevertheless, the introduction of Orphan Drug legislations has provided important incentives for the development of orphan drugs (i.e. drugs that have been abandoned or 'orphaned' by major drug companies). Moreover, recent studies on rare diseases, including inherited immunodeficiencies and metabolic disorders, have served not only to alleviate the plight of patients with rare diseases, but also yielded valuable information on biological processes of relevance for other, more common conditions. These lessons, along with the crucial importance of cooperation between academic institutions, pharmaceutical companies, patient advocacy groups and society in the elucidation of rare diseases, are highlighted in the present review.

Spectrum and clinical implications of syntaxin 11 gene mutations in familial haemophagocytic lymphohistiocytosis: association with disease-free remissions and haematopoietic malignancies

OBJECTIVE

To determine the frequency and spectrum of mutations in the gene encoding syntaxin 11 (STX11) in familial haemophagocytic lymphohistiocytosis (FHL), a rare autosomal recessive disorder of immune dysregulation characterised by a defect in natural killer cell function.

METHODS

Mutational analysis of STX11 by direct sequencing was done in 28 FHL families that did not harbour perforin mutations, previously identified in some FHL patients. A detailed investigation of clinical features of these patients was also undertaken.

RESULTS

Two different STX11 mutations were identified, one nonsense mutation and one deletion, affecting six of 34 children in four of 28 unrelated PRF1 negative families. Both mutations have been reported before. Three patients experienced long periods (> or = 1 year) in remission without specific treatment, which is very uncommon in this disease. Despite the milder phenotype, some children with STX11 mutations developed severe psychomotor retardation. Two of the six patients harbouring STX11 gene defects developed myelodysplastic syndrome (MDS) or acute myelogenous leukaemia (AML).

CONCLUSIONS

STX11 gene mutations were found in 14% of the PRF1 negative FHL families included in the present cohort. These results suggest that STX11 gene mutations may be associated with secondary malignancies (MDS/AML), and that there is segregation of specific clinical features in FHL patients with an underlying genotype.

Risk factors for diabetes insipidus in langerhans cell histiocytosis

BACKGROUND

Diabetes insipidus (DI) is the most frequent central nervous system (CNS)-related permanent consequence in Langerhans cell histiocytosis (LCH), which mostly requires life-long hormone replacement therapy. In an attempt to define the population at risk for DI, 1,741 patients with LCH registered on the trials DALHX 83 and DALHX 90, LCH I and LCH II were studied.

RESULTS

Overall 212 of 1,741 patients (12%) was reported to have DI. In 102 of 1,741 patients (6%) DI was present at diagnosis of LCH. One thousand one hundred eighty three of 1,539 patients without DI at diagnosis had follow up information. One hundred ten of these (9%) later developed DI. The risk of developing DI was 20% at 15 years after diagnosis. Multisystem disease patients at diagnosis carried a 4.6-fold risk for DI compared to single system patients. Craniofacial lesions, in particular in the "ear," "eye," and oral region were associated with a significantly increased risk for DI (relative hazard rate, RHR 1.7), independent of the extent of disease. No influence of the duration of therapy could be determined, but the duration of initial disease activity (RHR 1.5) and the occurrence of reactivations (RHR 3.5) significantly increased the risk for DI.

CONCLUSIONS

Patients with multisystem disease and craniofacial involvement at diagnosis, in particular of the "ear," "eye," and the oral region carry a significantly increased risk to develop DI during their course. This risk is augmented when the disease remains active for a longer period or reactivates.

Findings in familial haemophagocytic lymphohistiocytosis prior to symptomatic presentation

Familial haemophagocytic lymphohistiocytosis (FHL) is a rare, autosomal recessive disease of infancy and early childhood clinically characterized by fever, hepatosplenomegaly, lymphadenopathy, rash, neurological symptoms and icterus. Common laboratory findings include cytopenia, elevated liver enzymes, hyperbiliriubinaemia, hypofibrinogenaemia and hypertriglyceridaemia. The natural killer cell function is frequently decreased or absent. A diffuse lymphohistiocytic infiltration is seen in the reticuloendothelial system, often with haemophagocytosis. Molecular diagnosis is available in a minority of FHL families. Without adequate treatment and bone-marrow transplantation, the disease is fatal. A 6-wk-old child with FHL is presented. Shortly before the clinical onset of the disease, blood testing and bone-marrow examination had been carried out. All results were considered normal at that time.

CONCLUSION

Blood tests and bone-marrow examination may be normal shortly before the clinical presentation and therefore do not exclude the diagnosis of FHL. There is a need for extended molecular diagnostic possibilities.

Familial hemophagocytic lymphohistiocytosis: too little cell death can seriously damage your health

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare and fatal disease of early childhood characterized by a non-malignant accumulation of activated T lymphocytes and histiocytes in the reticuloendothelial system. Moreover, immune system derangement, with prominent hypercytokinemia and low or absent cytotoxic T and natural killer (NK) cell activity, is a consistent feature of this autosomal recessive disorder. Recent work has demonstrated that the degree of spontaneous caspase activation in FHL lymphocytes is attenuated in vitro whereas Fas-mediated caspase activation and apoptosis induction remains unmitigated, and FHL can thus be distinguished from the related chronic disorder of immune regulation termed autoimmune lymphoproliferative syndrome or ALPS. However, subsequent studies have identified mutations in the gene encoding perforin, a cytotoxic granule constituent required for apoptotic killing of target cells, in a number of FHL patients. Hence, the underlying defect in FHL may be conceived of as a lack of apoptosis triggering within the immune system, rather than apoptosis resistance per se. These observations represent an important step in our understanding of the pathogenesis of FHL and also serve to emphasize the pivotal role of cellular (perforin-based) cytotoxicity in the regulation of immune homeostasis.

Pulmonary abnormalities at long-term follow-up of patients with Langerhans cell histiocytosis

BACKGROUND

In Langerhans cell histiocytosis (LCH) pulmonary involvement, which is often initially asymptomatic, may contribute to significant morbidity and mortality. To determine the long-term prognosis, a cross-sectional study was undertaken.

PROCEDURE

Forty-one patients with > or = 5 years follow-up after the diagnosis of LCH were interviewed and underwent physical examination, blood tests, a chest X-ray and a high-resolution CT (HRCT) of the lungs. All patients included had been referred to the Department of Pediatrics at the Karolinska Hospital in Stockholm between July 1962 and February 1990 (median follow-up 16 years). Biopsies from all patients were reviewed and confirmed to be consistent with LCH. Information on previous clinical features including treatment and the results of chest X-rays were also collected for risk factor analysis.

RESULTS

Radiographic abnormalities of the lungs (cysts and/or emphysema), found in 10/41 (24%) at follow-up, were classified into five groups according to the extent of the cysts. These patients had more often suffered from multisystem than from single-system disease (P = 0.01), were significantly older at diagnosis (P < 0.001), and had been more heavily treated with chemotherapy and/or radiotherapy. They were also more frequently smokers (P < 0.0001) and 7/10 (70%) had suffered lung involvement at diagnosis. At the time of diagnosis of the pulmonary involvement, 4/10 (40%) patients had respiratory symptoms, but only 2/10 (20%) had symptoms at follow-up.

CONCLUSIONS

Ten (24%) of the 41 patients had abnormal findings on radiological examination of the lungs at long-term follow-up and seven are or had been smokers. It is of great importance that patients with LCH be informed about smoking-related pulmonary morbidity. Prolonged monitoring of the lungs for smokers and patients with known pulmonary involvement is recommended.

Detection of Langerhans cell histiocytosis lesions with somatostatin analogue scintigraphy--a preliminary report

BACKGROUND

Langerhans cell histiocytosis (LCH) is a disease where granulomatous lesions occur in various organs of the body. The etiology and pathogenesis remain unknown. Inflammatory destructive activity give rise to a wide range of clinical symptoms, including fractures, skin lesions, pulmonary fibrosis, endocrinopathies, and central nervous system deterioration. Since disease activity may ultimately lead to fibrosis and organ damage, it is important to have diagnostic tools to detect disease activity early.

PROCEDURE

The present study was undertaken in order to evaluate whether somatostatin analogue scintigraphy ((111)In-pentetreotide or OctreoScan could be used in detecting LCH granulomas and to compare this method with the radiologic methods used today in LCH diagnosis and follow-up. The somatostatin analogue octreotide used here binds to the cell membrane of activated lymphocytes expressing somatostatin receptors.

RESULTS

In five out of six children studied, LCH lesions detected by other means were also detected with (111)In-pentetreotide. It can be speculated that the lesion in the remaining patient was not active at the time of investigation. In addition, in two of the patients signs of disease activity not previously known were revealed.

CONCLUSION

(111)In-pentetreotide can be used to detect active LCH lesions. Since the biologically active somatostatin analogue decreases inflammatory activity, this may also be of therapeutic value in selected patients with LCH. More studies are needed to evaluate the diagnostic and potential therapeutic usefulness of this radionuclide.

Smoking preceded pulmonary involvement in adults with Langerhans cell histiocytosis diagnosed in childhood

Two patients with childhood Langerhans cell histiocytosis (LCH) (aged 2 and 6 y at diagnosis) in whom pulmonary involvement was diagnosed in adulthood, 23 and 12 y later, respectively, are presented. In each patient, smoking preceded the diagnosis of pulmonary involvement by 3 y, providing further evidence that smoking is a risk factor in the development of pulmonary LCH.

[Familial hemophagocytic lymphohistiocytosis: diagnosis, treatment and pathophysiological mechanisms]

Familial hemophagocytic lymphohistiocytosis (FHL) is an invariably fatal disease typically seen in infancy and early childhood, with a median survival without therapy of two months. It is characterized by prolonged fever, hepatosplenomegaly, cytopenia, and deficient NK-cell activity and T-cell cytotoxic capacity. Severe neurological symptoms as well as coagulation disorders and abnormalities in liver function and lipid status may also develop. Since the mid 1980's there has been a remarkable increase in our understanding of this disease. In a large-scale international collaborative effort mediated through the Histiocyte Society, diagnostic criteria and an international treatment protocol (HLH-94) based on immunochemotherapy and BMT have been developed. A large proportion of affected children can now be cured and, moreover, successful chemotherapy in utero of FHL has been achieved. It has been shown that the symptoms and signs are mediated through a pronounced hypercytokinemia. Previous suggestions that FHL may be caused by a deficiency in apoptosis were recently confirmed when perforin gene defects were described, which may well explain the disastrous lymphohistiocytic accumulation and subsequent T-cell activation.

[Apoptosis required for maintenance of homeostasis: familial hemophagocytic lymphohistiocytosis caused by too little cell death]

Apoptosis or programmed cell death is essential for the maintenance of tissue homeostasis. Recent studies have implicated the dysregulation of apoptosis in a plethora of human diseases. Hence, perturbation of the death program intrinsic to every cell may result in essentially too little or too much apoptosis, which may in turn lead to proliferative or degenerative diseases respectively. In the present review, we discuss our current molecular understanding of the apoptotic process and its possible role in human disease, with particular emphasis on the rare and invariably fatal disease of early childhood, termed familial hemophagocytic lymphohistiocytosis, in which mutations in the perforin gene were recently identified.

[Parvovirus B19 infection--an incidious chameleon]

Parvovirus B19 is a common source of infection with a seroprevalence of 60-70 per cent in the adult population. The most common manifestation is erythema infectiosum ("fifth disease"), with exanthem, fever and upper airway symptoms in children. The infection can give rise to a multifaceted clinical picture and is probably underdiagnosed, particularly in risk groups (individuals with haemolytic anaemia or immunosuppression, and fetuses). Serological diagnosis can now be complemented with the demonstration of viral DNA using the PCR (polymerase chain reaction) test in various body fluids, or tissue biopsy. Recent years have witnessed manifest increase in clinical knowledge of parvovirus B19-associated complications, and their diagnosis and treatment.

Phosphatidylserine exposure during apoptosis is a cell-type-specific event and does not correlate with plasma membrane phospholipid scramblase expression

Phosphatidylserine (PS) exposure on the surface of cells has been considered a characteristic feature of apoptosis. However, we demonstrate herein that externalization of PS occurs in a cell-type-specific, albeit caspase-dependent, manner. Moreover, we could find no correlation in six different cell lines between the level of expression of the phospholipid (PL) scramblase and the capacity of these cells to externalize PS during apoptosis. Overexpression of PL scramblase in Raji cells, which exhibit low constitutive expression of this enzyme, by retroviral transduction of PL scramblase or treatment of the cells with interferon-alpha, failed to confer the capacity to expose PS in response to apoptotic stimuli. However, the lack of PS exposure in some cell types was not due to their inability to translocate PS molecules to the cell surface, since incubation with thiol reactive agents, such as N-ethylmaleimide, disulfiram and diamide, yielded rapid and pronounced PS exposure in all cell lines. These data suggest that plasma membrane PS exposure is not an obligatory component of the apoptotic phenotype, and that PL scramblase is not the sole determinant of PS externalization in apoptotic cells when this occurs.

Perforin gene defects in familial hemophagocytic lymphohistiocytosis

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare, rapidly fatal, autosomal recessive immune disorder characterized by uncontrolled activation of T cells and macrophages and overproduction of inflammatory cytokines. Linkage analyses indicate that FHL is genetically heterogeneous and linked to 9q21.3-22, 10q21-22, or another as yet undefined locus. Sequencing of the coding regions of the perforin gene of eight unrelated 10q21-22-linked FHL patients revealed homozygous nonsense mutations in four patients and missense mutations in the other four patients. Cultured lymphocytes from patients had defective cytotoxic activity, and immunostaining revealed little or no perforin in the granules. Thus, defects in perforin are responsible for 10q21-22-linked FHL. Perforin-based effector systems are, therefore, involved not only in the lysis of abnormal cells but also in the down-regulation of cellular immune activation.

[Parvovirus B19 infection--an insidious chameleon]

Parvovirus B19 is a common source of infection with a seroprevalence of 60-70 per cent in the adult population. The most common manifestation is erythema infectiosum ('fifth disease'), with exanthem, fever and upper airway symptoms in children. The infection can give rise to a multifacetted clinical picture and is probably underdiagnosed, particularly in risk groups (individuals with haemolytic anaemia or immunosuppression, and fetuses). Serological diagnosis can now be complemented with the demonstration of viral DNA using the PCR (polymerase chain reaction) test in various body fluids, or tissue biopsy. Recent years have witnessed manifest increase in clinical knowledge of parvovirus B19-associated complications, and their diagnosis and treatment.

Induction of apoptosis and caspase activation in cells obtained from familial haemophagocytic lymphohistiocytosis patients

Familial haemophagocytic lymphohistiocytosis (FHL) is a rare and uniformly fatal disorder of early childhood characterized by fever, hepatosplenomegaly, cytopenia and widespread infiltration of vital organs by activated lymphocytes and macrophages. In order to test whether the massive accumulation of immune cells in these patients is associated with a perturbation of apoptosis, lymphocytes were isolated from eight patients and subjected to the chemotherapeutic agent etoposide or agonistic anti-Fas monoclonal antibodies in vitro. These stimuli elicited a normal apoptotic response in FHL patient cells when compared to healthy controls, as determined by phosphatidylserine exposure, DNA fragmentation, in vitro cleavage of the caspase-3-like substrate aspartate-glutamate-valine-aspartate-7-amino-4-methyl-coumarin (DEVD-AMC) and proteolysis of the anti-apoptotic protein Bcl-2. In addition, the degree of constitutive and Fas-triggered apoptosis in freshly isolated neutrophils was monitored in three children, with similar results. These studies indicate that immune cells derived from FHL patients are not inherently resistant to apoptosis induction. Specifically, etoposide-induced and Fas-triggered activation of intracellular caspases appears to remain intact in these individuals. However, the degree of spontaneous activation of caspase-3-like enzymes in activated lymphocytes was attenuated in three of the four patients tested prior to initiation of therapy, suggesting a possible biological deficiency in these individuals.

Cleavage of Bcl-2 is an early event in chemotherapy-induced apoptosis of human myeloid leukemia cells

The proto-oncogene product Bcl-2 protects a wide variety of cell types from apoptosis via a hitherto unknown mechanism. Bcl-2 has been shown to function upstream of the death proteases (caspases) in some, but not all, occurrences of apoptotic cell death. Using the myeloid leukemic cell line P39 we report the chemotherapy-induced caspase-dependent cleavage of endogenous Bcl-2. Etoposide treatment of these cells triggered a time-dependent activation of type II and type III caspases and cleavage of Bcl-2 yielding a 23 kDa cleavage fragment. The emergence of this cleavage product was blocked by the general caspase inhibitor zVAD-fmk, as well as the type III caspase inhibitor IETD-fmk and the caspase-9-selective inhibitor LEHD-fmk, while the type II caspase inhibitor DEVD-fmk proved considerably less efficient. Bcl-2 cleavage preceded cleavage of the known caspase-3 substrate, poly(ADP-ribose) polymerase (PARP), as well as that of the caspase-6 substrate, lamin B, indicating that Bcl-2 cleavage is a relatively early event in the apoptosis cascade in this experimental model. While evidence for cleavage of Bcl-2 in several subcellular compartments of etoposide-treated cells was obtained, this cleavage was detected predominantly in the mitochondrial fraction, thus providing further support for the central role of mitochondria in apoptosis. Caspase-mediated cleavage following etoposide treatment of these myeloid leukemic cells may represent a means for the attenuation of Bcl-2 function upon apoptosis induction.

Effective control of Epstein-Barr virus-related hemophagocytic lymphohistiocytosis with immunochemotherapy. Histiocyte Society

The familial form of hemophagocytic lymphohistiocytosis (HLH) is a lethal disorder. Although the prognosis for Epstein-Barr virus-associated HLH (EBV-HLH) remains uncertain, numerous reports indicate that it can also be fatal in a substantial proportion of cases. We therefore assessed the potential of immunochemotherapy with a core combination of steroids and etoposide to control EBV-HLH in 17 infants and children who met stringent diagnostic criteria for this reactive disorder of the mononuclear phagocyte system. Treatment of life-threatening emergencies was left to the discretion of participating investigators and typically included either intravenous Ig or cyclosporin A (CSA). Five patients (29%) entered complete remission during the induction phase (1 to 2 months), whereas 10 others (57%) required additional treatment to achieve this status. In 2 cases, immunochemotherapy was ineffective, prompting allogeneic bone marrow transplantation. Severe but reversible myelosuppression was a common finding; adverse late sequelae were limited to epileptic activity in one child and chronic EBV infection in 2 others. Fourteen of the 17 patients treated with immunochemotherapy have maintained their complete responses for 4+ to 39+ months (median, 15+ months), suggesting a low probability of disease recurrence. These results provide a new perspective on EBV-HLH, showing effective control (and perhaps cure) of the majority of EBV-HLH cases without bone marrow transplantation, using steroids and etoposide, with or without immunomodulatory agents.

Successful extracorporeal membrane oxygenation in four children with malignant disease and severe Pneumocystis carinii pneumonia

BACKGROUND

Toxic deaths due to intensified treatment are of increasing concern in view of the generally improved prognosis for children with malignancies. Pneumocystis carinii pneumonia (PCP) during immunosuppressive treatment in children with malignancies is a severe complication with a poor prognosis if mechanical ventilation is required. Extracorporeal membrane oxygenation (ECMO) is a recognized technique that provides temporary respiratory support for patients with intractable respiratory failure.

PROCEDURE

We here report successful ECMO support in four children with PCP, secondary to chemotherapy-induced immunosuppression, in whom the respiratory situation deteriorated despite pharmacological treatment and mechanical ventilation. The duration of ECMO was 7-43 days.

RESULTS

Three children with acute lymphoblastic leukemia recovered from their PCP to continue chemotherapy and are now in complete continuous remission. Their pulmonary function normalized completely during 6-12 months after ECMO therapy. One child with a primitive neuroectodermal tumor survived the PCP and was off ECMO for 11 days before succumbing to unrelated complications.

CONCLUSIONS

We conclude that ECMO offers an important means of respiratory support in children with severe PCP that can also be adopted during treatment for malignant disease.

Involvement of caspases in neutrophil apoptosis: regulation by reactive oxygen species

Human neutrophils have a short half-life and are believed to die by apoptosis or programmed cell death both in vivo and in vitro. We found that caspases are activated in a time-dependent manner in neutrophils undergoing spontaneous apoptosis, concomitant with other characteristic features of apoptotic cell death such as morphologic changes, phosphatidylserine (PS) exposure, and DNA fragmentation. The treatment of neutrophils with agonistic anti-Fas monoclonal antibodies (MoAbs) significantly accelerated this process. However, in cells treated with the potent neutrophil activator phorbol 12-myristate 13-acetate (PMA), caspase activity was only evident after pharmacologic inhibition of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Similarily, inhibition of the NADPH oxidase in constitutive and Fas/APO-1-triggered apoptosis resulted in increased rather than suppressed levels of caspase activity, suggesting that reactive oxygen species may prevent caspases from functioning optimally in these cells. Moreover, oxidants generated via the NADPH oxidase were essential for PS exposure during PMA-induced cell death, but not for neutrophils undergoing spontaneous apoptosis. We conclude that caspases are an important component of constitutive and Fas/APO-1-triggered neutrophil apoptosis. However, these redox sensitive enzymes are suppressed in activated neutrophils, and an alternate oxidant-dependent pathway is used to mediate PS exposure and neutrophil clearance under these conditions.

Elevated erythrocyte sedimentation rate and thrombocytosis as possible indicators of active disease in Langerhans' cell histiocytosis

Langerhans' cell histiocytosis (LCH) is a disease with an unpredictable course and unpredictable reactivations. Since active disease may cause life-long sequelae, early detection of reactivation is important. The usefulness of erythrocyte sedimentation rate (ESR) and thrombocytosis as indicators of disease activity in patients with LCH were examined. The mean values for ESR and platelet count for each quarter of a year were compiled. The means of all the ESR estimates (n = 76) during each quarter of a year with active disease was 21 mm h(-1), with intermediate disease activity 11 mm h(-1) and with resolution 7 mm h(-1). The corresponding platelet count estimates (n = 139) were 433 x 10(9) l(-1), 365 x 10(9) l(-1) and 304 x 10(9) l(-1), respectively. In conclusion, elevated ESR and platelet count may be clinically valuable indicators of disease activity in LCH.

Persistent B19 parvovirus infection in pediatric malignancies

BACKGROUND AND PROCEDURE

The frequency and clinical importance of parvovirus B19 infection were studied in children investigated or treated for various malignancies and cytopenias.

RESULTS

B19 infection was thus demonstrated in six out of 53 unselected children with malignancies by bone marrow examination, using the B19, DNA-specific, polymerase chain reaction (PCR). Examinations using the PCR in serum samples were equally or less sensitive than in bone marrow samples. One of the children had a persistent B19 infection during maintenance therapy for acute lymphoblastic leukemia. She developed a prolonged and severe cytopenia, and the clinical signs included facial rash, chills, high undulating fever, and pharyngitis. She also seroconverted and became B19 IgM-antibody positive during the study period.

CONCLUSIONS

Parvovirus B19 infection was detected in 10% of the children and was either asymptomatic or was associated with severe and prolonged cytopenia. Bone marrow examinations are recommended for the detection of B19 DNA in immunosuppressed children.

Infection- and malignancy-associated hemophagocytic syndromes. Secondary hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases in which a T-cell induced, uncontrolled activation of phagocytosing macrophages may lead to fever, organomegaly, and pancytopenia. The underlying immunologic disturbance can either be genetically transmitted, like in FHL, or acquired, as in IAHS or MAHS. Triggering infections can be found in all these diseases and do not allow a reliable differentiation. An international treatment protocol has been developed for FHL. IAHS and MAHS also have a high fatality rate, justifying immunomodulatory treatment if the disease is progressive.

Familial hemophagocytic lymphohistiocytosis. Primary hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases including the rapidly fatal autosomal recessive disease of familial hemophagocytic lymphohistiocytosis (FHL). The onset is usually during the first years of life with fever, cytopenia, and hepatosplenomegaly. Neurologic symptoms may supervene. Similar symptoms may occur in the infection-(virus-)associated or malignancy-associated hemophagocytic syndromes (IAHS/MAHS). Triggering infections can be found in all these diseases and do not allow for reliable differentiation. An international treatment protocol (HLH-94) has been developed for FHL, but immunomodulatory treatment may be justified in IAHS and MAHS as well, since they also have a high fatality rate.

Autopsy findings in 27 children with haemophagocytic lymphohistiocytosis

AIMS

Primary haemophagocytic lymphohistiocytosis (HLH) is a fatal childhood disorder. The diagnosis is difficult to establish, clinically as well as histopathologically, and it is markedly underdiagnosed. Because of these difficulties, we wanted to elucidate the histopathological findings in population-based patient material.

METHODS AND RESULTS

The post-mortem findings in 27 children with primary HLH diagnosed in Sweden between 1971 and 1986 was reviewed. Twelve of these patients had an affected sibling and three additional children had parental consanguinity. Some of the children showed generalized disease, whereas in others only one or a few organs were affected. The major histological alteration was an accumulation of primarily lymphocytes, but also of histiocytes, some of which exhibited evidence of haemophagocytosis. The haemophagocytic activity may be difficult to detect if there are pronounced post-mortem changes, particularly in the spleen, and it is therefore preferable to perform the autopsy as soon as possible after death in order to minimize autolysis. Haemophagocytosis was most commonly observed in the spleen (17/24), the lymph nodes (17/23) and the bone marrow (9/23), indicating that a negative bone marrow examination does not rule out this diagnosis. Three additional patients had discrete signs of haemophagocytosis in the bone marrow. In the spleen, the lymph nodes and the bone marrow, lymphocytic depletion, pronounced in some cases, could be observed, even without prior treatment with steroids or cytostatics. In the liver, most of the patients demonstrated an infiltration of lymphocytes into the portal tracts similar to that seen in chronic persistent hepatitis (22/27), a finding which is uncommon in infancy and therefore suggestive of the diagnosis HLH. Other organs involved included the thymus, lungs intestine, pancreas, kidney, heart and striated muscle.

CONCLUSIONS

The diagnosis of HLH must be based on clinical, histological and additional laboratory findings. A negative bone marrow examination is common. Previous treatment with steroids and/or cytostatic drugs may attenuate or even eliminate the typical histological findings. Liver findings similar to those in chronic persistent hepatitis are common.

Down-regulation of lymphokine synthesis by intravenous gammaglobulin is dependent upon accessory cells

We have investigated one mechanism by which pooled human IgG preparations for intravenous use (i.v.Ig) selectively down-regulates lymphokine synthesis. Effects of i.v.Ig on cytokine production were quantified at a cellular level by using an immunocytochemical staining technique. Pure T-lymphocyte preparations (from the peripheral blood of healthy adults) were separated by the use of magnetic beads and were then used in parallel experiments with unfractionated mononuclear cells (MNC). Cell activation was induced either by a combination of the protein kinase C activator, phorbol 12-myristate 13-acetate (PMA), and the calcium ionophore, ionomycin, or by direct ligation of the T-cell receptor, using immobilized anti-CD3 monoclonal antibody (MoAb). Cells were cultured in the presence or absence of i.v.Ig and subsequently harvested and stained for the following cytokines: interleukin-2 (IL-2), interferon-gamma (IFN-gamma), tumour necrosis factor-beta (TNF-beta) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Assessment of the frequencies of positively stained cells was performed by manual microscopy and by computerized image analysis. Activation by PMA/ionomycin or by immobilized anti-CD3 MoAb induced substantial lymphokine production in both MNC and in purified T cells. Addition of i.v.Ig led to a diminished synthesis of all of the T-cell products studied in unfractionated MNC preparations, whereas production was maintained or occasionally increased in the purified T-cell preparations. These findings indicate that the immunomodulatory effect by i.v.Ig on T-cell activation and lymphokine production was dependent on accessory cells.

Transient red cell aplasia in siblings: a common environmental or a common hereditary factor?

During the years 1987-89, transient erythroblastopenia of childhood was diagnosed in 52 previously healthy Swedish children aged less than 4 y. Among these children there were four pairs of siblings, including one pair of identical female twins. This is a much higher familial occurrence than expected. The probability of finding 4 pairs of siblings with this disease in 50 families was estimated to be considerably less than 10-6. In the retrospectively analysed material, no environmental factor was implicated and no association with human leucocyte antigen could be proven. The twins demonstrated the disease simultaneously. Their anaemia was transient and did not recur, but showed certain features usually seen in congenital hypoplastic anaemia. The other pairs of siblings fulfilled the criteria for transient erythroblastopenia of childhood and several years elapsed between the development of the disease in siblings. Two of the fathers were reported to have had transient anaemia during their childhood. Our findings indicate that transient erythroblastopenia of childhood may involve hereditary factors, eventually demonstrating an autosomal dominant inheritance.

Contemporary classification of histiocytic disorders. The WHO Committee On Histiocytic/Reticulum Cell Proliferations. Reclassification Working Group of the Histiocyte Society

Pathologists and pediatric hematologist/ oncologists of the World Health Organization's Committee on Histiocytic/Reticulum Cell Proliferations and the Reclassification Working Group of the Histiocyte Society present a classification of the histiocytic disorders that primarily affect children. Nosology, based on the lineage of lesional cells and biological behavior, is related to the ontogeny of histiocytes (macrophages and dendritic cells of the immune system). Dendritic cell-related disorders of varied biological behavior are dominated by Langerhans cell histiocytosis, but separate secondary proliferations of dendritic cells must be differentiated. Juvenile xanthogranuloma represents a disorder of dermal dendrocytes, another dendritic cell of skin. The hemophagocytic syndromes are the most common of the macrophage-related disorders of varied biological behavior. Guidelines for distinguishing the exceedingly rare malignant diseases of histiocytes from large cell lymphomas through the use of a battery of special studies are provided.

Diamond-Blackfan anaemia: genetic homogeneity for a gene on chromosome 19q13 restricted to 1.8 Mb

Diamond-Blackfan anaemia (DBA; MIM#205900) is a rare disorder manifested as a pure red-cell aplasia in the neonatal period or in infancy. The clinical hallmark of DBA is a selective decrease in erythroid precursors and anaemia. Other lineages are usually normal and the peripheral white blood cell count is normal. In approximately one-third of cases, the disease is associated with a wide variety of congenital anomalies and malformations. Most cases are sporadic, but 10-20% of them follow a recessive or a dominant inheritance pattern. A female with DBA and a chromosomal translocation involving chromosome 19q was recently identified. We undertook a linkage analysis with chromosome 19 markers in multiplex DBA families of Swedish, French, Dutch, Arabic and Italian origin. Significant linkage to chromosome 19q13 was established for dominant and recessive inherited DBA with a peak lod score at D19S197 (Zmax = 7.08, theta = 0.00). Within this region, a submicroscopic de novo deletion of 3.3 Mb was identified in a patient with DBA. The deletion coincides with the translocation break-point and, together with key recombinations, restricts the DBA gene to a 1.8-Mb region. The results suggest that, despite its clinical heterogeneity, DBA is genetically homogeneous for a gene in 19q13.

Contemporary classification of histiocytic disorders. The WHO Committee On Histiocytic/Reticulum Cell Proliferations. Reclassification Working Group of the Histiocyte Society

Pathologists and pediatric hematologist/ oncologists of the World Health Organization's Committee on Histiocytic/Reticulum Cell Proliferations and the Reclassification Working Group of the Histiocyte Society present a classification of the histiocytic disorders that primarily affect children. Nosology, based on the lineage of lesional cells and biological behavior, is related to the ontogeny of histiocytes (macrophages and dendritic cells of the immune system). Dendritic cell-related disorders of varied biological behavior are dominated by Langerhans cell histiocytosis, but separate secondary proliferations of dendritic cells must be differentiated. Juvenile xanthogranuloma represents a disorder of dermal dendrocytes, another dendritic cell of skin. The hemophagocytic syndromes are the most common of the macrophage-related disorders of varied biological behavior. Guidelines for distinguishing the exceedingly rare malignant diseases of histiocytes from large cell lymphomas through the use of a battery of special studies are provided.

Neuropathologic findings and neurologic symptoms in twenty-three children with hemophagocytic lymphohistiocytosis

BACKGROUND

Primary hemophagocytic lymphohistiocytosis (HLH) is an autosomal recessive disorder with very high mortality rates, mainly affecting infants and young children, which is characterized by fever, hepatosplenomegaly, and cytopenias. Of great clinical importance are the neurologic symptoms, which are common and may even dominate the clinical picture and precede the systemic presentation. These symptoms are extremely variable, ranging from irritability, bulging fontanelle, and neck stiffness, to convulsions, cranial nerve palsies, ataxia, hemiplegia/tetraplegia, and unconsciousness.

METHODS

To elucidate this neurologic involvement further, we reviewed the neuropathologic postmortem findings from 23 children and their neurologic symptoms.

RESULTS

Macroscopically, edema was present in many cases, and in some with advanced disease, softening and destruction of the tissue were conspicuous. The microscopic picture was exceedingly variable, ranging from almost normal to very advanced changes. In the mildest form of HLH, only the meninges were involved with infiltration of lymphocytes and macrophages (stage I), whereas more advanced cases in addition also showed perivascular infiltrates (stage II). In even more advanced disease there was also a diffuse infiltration in the tissue (stage III), as well as a multifocal necrosis. A prominent astrogliosis was present in such cases. Hemophagocytosis was seen in most patients, most commonly in the leptomeninges.

CONCLUSIONS

HLH affecting the central nervous system imitates several neurologic disorders and may be misdiagnosed. A staging system for the neuropathologic findings is presented. In children with obscure central nervous systems symptoms and a progressive encephalopathy, the diagnosis of HLH may be considered, in particular because treatments are available.

Prevalence and treatment of chronic idiopathic thrombocytopenic purpura of childhood in Sweden

The frequency and treatment of children with chronic idiopathic thrombocytopenic purpura in Sweden were characterized using a national enquiry based on a questionnaire. Seventy-five children diagnosed as having chronic idiopathic thrombocytopenic purpura on 1 September 1993 were identified. The prevalence in children between 0.5 and 15.5 years of age was calculated to be 4.6/100,000. The median age at the time of diagnosis was 5 years and the male/female ratio was 1:1.2. Almost half of the patients (43%) were not treated at all during the disease. Steroids (43%) and intravenous immunoglobulin (25%) were most commonly used. Only two children were splenectomized.

Transient hypertriglyceridemia of infancy

A premature boy who had suffered from IRDS, bronchopulmonary dysplasia and retinopathy of prematurity developed massive hypertriglyceridemia (48.1 mmol/L) together with moderate hypercholesterolemia (12.6 mmol/L) at 5 months of age. Lipoprotein electrophoresis revealed a marked elevation of the level of the very low density lipoprotein fraction. There was a moderate decrease in the activity of a lipolytic enzyme, lipoprotein lipase (LPL). The child had neither liver or renal disorder nor any inflammatory disease. The hyperlipidemia disappeared spontaneously at the age of 3 years. The cause of the decreased LPL activity could not be established. A partial genetic deficiency in lipoprotein lipase appears the most likely explanation, since no signs of secondary lowering of LPL activity could be found.

Elevated circulating levels of interleukin-1 receptor antagonist but not IL-1 agonists in hemophagocytic lymphohistiocytosis

The familial form of hemophagocytic lymphohistiocytosis (HLH) is an inherited disease with disturbed immunomodulation and characterized by fever, hepatosplenomegaly, cytopenia, hypertriglyceridemia, and coagulopathy, i.e., findings which are similar to many of the reported biological effects of the inflammatory cytokines. Due to the previously shown hypercytokinemia in active HLH with elevated levels of interleukin (IL)-6, tumor necrosis factor-alpha, and interferon-gamma, it has been suggested that cytokine dysregulation may be of pathophysiological importance. Here we have assayed the serum levels of the members of the IL-1 ligand family, the two agonists IL-1 alpha and IL-1 beta and the antagonist IL-1 receptor antagonist (IL-1ra), in nine children with HLH and cerebrospinal fluid (CSF) specimens from four children. Serum IL-1ra was elevated in all patients with active disease to a degree which correlated well with disease activity. Furthermore, the levels decreased day by day during treatment of a patient who suffered a relapse. Moreover, high levels of IL-1ra were also detected in CSF during active disease. However, IL-1 beta levels were all within normal limits and circulating IL-1 alpha levels were normal in all but two patients.

Intralesional steroids in Langerhans cell histiocytosis of bone

Langerhans cell histiocytosis may involve single or multiple organ systems. Bone involvement is the most common feature. We have examined retrospectively the effects of 20 intralesional injections of steroids into bone in seven patients seen at our department from 1988 to 1993. Most of these injections (75%) relieved the symptoms, and no side-effects were observed. However, injections into the jaw were seldom effective. Our results suggest that the dose of the steroids administered is of importance.

Hemophagocytic lymphohistiocytosis. Report of 122 children from the International Registry. FHL Study Group of the Histiocyte Society

Hemophagocytic lymphohistiocytosis (HLH) is a rare, often fatal, disease of early infancy. The diagnosis of HLH is frequently delayed or made at autopsy because no genetic or biologic marker has been identified. To improve the classification and treatment of HLH, the Histiocyte Society has established an 'International Registry for HLH'. Data collected included family history, clinical and laboratory features at the onset of illness, and treatment outcome. Stringent diagnostic criteria (ie fever, splenomegaly, cytopenia, hypertriglyceridemia, and/or hypofibrinogenemia, and hemophagocytosis without evidence of malignancy) were used for patient selection. One hundred and twenty-two patients (61 males, 61 females) were enrolled from 17 centers in 11 countries. The rate of parental consanguinity was 24%. A positive family history was reported in 49% of cases including two pairs of affected male twins. The median age at disease onset was 2.9 months, with no difference between familial and sporadic cases. Age at onset was similar in affected sibs from 10 of 14 families, but in four up to 3-year differences were observed. Hemophagocytosis was present at diagnosis in 75%. An associated infection (usually by common viral pathogens) was reported in 50 of the 122 (41%) cases, of which 25 had familial disease. Natural killer activity was impaired in 36 of 37 patients studied. Chromosome analysis was normal in all tested patients. A decreased frequency of HLA-B7 and B8 alleles and increased frequency of HLA-B21 and DQ3 were observed. The estimated 5-year survival (SE) was 21% (18.7) for all patients. It was 66% (37.8) for patients who received allogeneic bone marrow transplant and 10.1% (9.6) for patients treated with chemotherapy alone (P=0.0001). None of the previously proposed prognostic indicators (age, associated infection, cerebrospinal fluid pleocytosis, family history) correlated with treatment outcome.

Bone marrow transplantation in two children with congenital amegakaryocytic thrombocytopenia

Two thrombocytopenic infants with essentially normal initial bone marrow morphology were believed to have idiopathic thrombocytopenic purpura. However, they failed to respond to steroids and intravenous immunoglobulins and had a normal platelet recovery after transfusions. The diagnosis was revised to congenital amegakaryocytic thrombocytopenia after bone marrow biopsies, which revealed a marked paucity of megakaryocytes. Repeated biopsies disclosed gradually decreasing numbers of megakaryocytes and increasing marrow hypoplasia. At the ages of 42 and 22 months the children underwent allogeneic bone marrow transplants, one of them with an unrelated marrow donor. Both patients are well with good engraftment of donor marrow and normal peripheral blood counts, 31 and 12 months after BMT, respectively.

Allogeneic bone marrow transplantation for hemophagocytic lymphohistiocytosis in Sweden

Six children (aged 9 months to 10 and 5/12 years) with hemophagocytic lymphohistiocytosis (HLH) have undergone allogeneic BMT in Sweden. In two of the children unrelated donors were used. Parents were available as donors in two of the cases and siblings in the other two. Conditioning before BMT consisted of etoposide, busulfan and cyclophosphamide with the addition of ATG in two cases and OKT 3 in one case. For post-transplant immunosuppression, i.v. methotrexate and cyclosporin A (CsA) were used in five cases, and in one child CsA was combined with methylprednisolone. Of the six children, four are alive and well 2 and 3/12 to 3 and 1/12 years after BMT. One child, who had an unrelated donor with one DR-antigen mismatch, died 30 days after BMT of fulminant grade IV GVHD. Another patients, seropositive for CMV, received marrow from an unrelated HLA-A, -B, -DR and -DP identical donor. After an initially uneventful course, CMV was isolated from her leukocytes. Seven months after BMT she developed a progressive obstructive chronic bronchiolitis and succumbed to respiratory insufficiency 14 months after the transplant. This study supports the view that BMT is the treatment of choice in HLH, particularly if an HLA-identical related donor is available.

Kala-azar in a one-year-old Swedish child. Diagnostic difficulties because of active hemophagocytosis

A one-year-old Swedish boy developed kala-azar six months after a holiday in Spain. Upon visiting the hospital after one week of illness he demonstrated clinical and laboratory findings of fever, splenomegaly and cytopenia. A fine-needle aspiration biopsy of the spleen revealed hemophagocytosis and he had increased serum levels of the cytokines tumor necrosis factor-alpha and interferon-gamma. Initially, a diagnosis of hemophagocytic lymphohistiocytosis was made. Re-evaluation of the spleen smears and of the bone marrow aspiration revealed Leishmania parasites and subsequent therapy with sodium stibogluconate was successful. This patient illustrates the interesting similarities between these two disorders involving the mononuclear phagocyte system as well as the problems involved in differential diagnosis. This case also reminds us of the possibility of contracting visceral leishmaniasis in Mediterranean countries.