Lymphohistiocytosis: a multi-factorial syndrome of macrophagic activation clinico-pathological study of 38 cases

History of Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a severe cytokine storm syndrome (CSS), which until the turn of the century, was barely known but is now receiving increased attention. The history of HLH dates back to 1939 when it was first described in adults, to be followed in 1952 by the first description of its primary, familial form in children. Secondary forms of HLH are far more frequent and occur with infections, malignancies, metabolic diseases, iatrogenic immune suppression, and autoinflammatory/autoimmune diseases. Identification of the genetic defects leading to the defective function of natural killer (NK) cells and cytotoxic T cells as well as the corresponding mouse models have revolutionized our understanding of HLH and of immune function. Diagnosis relies on clinical and laboratory criteria; functional and genetic tests can help separate primary from secondary forms. Treatment with immunochemotherapy and hematopoietic stem cell transplantation has considerably improved survival in children with primary HLH, a formerly uniformly fatal disease.

Case Report: Hemophagocytic Lymphocytosis in a Patient With Glutaric Aciduria Type IIC

Hemophagocytic lymphocytosis (HLH) is a rare disease caused by inborn errors of immunity (IEI), secondary to infection, lymphoma or autoimmune disorders, but we often overlook the fact that HLH can be secondary to inborn errors of metabolism (IEM). Here, we describe a patient who was diagnosed with glutaric aciduria type IIC complicated by features suggestive of possible HLH. The diagnosis of glutaric aciduria type IIC, a IEM, was confirmed by whole exome sequencing. The patient was treated with coenzyme Q10 and riboflavin which effectively improved her liver function. During treatment, the patient developed severe anemia and thrombocytopenia. Persistent fever, splenomegaly, cytopenias, increased ferritin, hypertriglyceridemia, hypofibrinogenemia, and hemophagocytosis in the bone marrow pointed to the diagnosis of HLH; however, the patient eventually died of gastrointestinal bleeding. After other potential causes were ruled out, the patient was diagnosed with glutaric aciduria type IIC complicated by features suggestive of possible HLH. When cytopenias occurs in IEM patients, HLH is a possible complication that cannot be ignored. This case suggests a possible relationship between IEM and risk for immune dysregulation.

Challenges in the diagnosis of hemophagocytic lymphohistiocytosis: Recommendations from the North American Consortium for Histiocytosis (NACHO)

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of pathologic immune activation, often associated with genetic defects of lymphocyte cytotoxicity. Though a distinctive constellation of features has been described for HLH, diagnosis remains challenging as patients have diverse presentations associated with a variety of triggers. We propose two concepts to clarify how HLH is diagnosed and treated: within the broader syndrome of HLH, "HLH disease" should be distinguished from "HLH disease mimics" and HLH subtypes should be categorized by specific etiologic associations, not the ambiguous dichotomy of "primary" and "secondary." We provide expert-based advice regarding the diagnosis and initiation of treatment for patients with HLH, rooted in improved understanding of its pathophysiology.

Childhood central nervous system vasculitis

Inflammatory brain diseases in childhood are underrecognized and lead to devastating yet potentially reversible deficits. New-onset neurologic or psychiatric deficits in previously healthy children mandate an evaluation for an underlying inflammatory brain disease. Distinct disease entities, such as central nervous system (CNS) vasculitis, are now being increasingly reported in children. Clinical symptoms, initial laboratory test, and neuroimaging studies help to differentiate between different causes; however, more invasive tests, such as lumbar puncture, conventional angiography, and/or brain biopsy, are usually necessary before the start of treatment. This article focuses on childhood CNS vasculitis.

Familial hemophagocytic lymphohistiocytosis: clinical and neuroradiological findings and review of the literature

BACKGROUND

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare multisystem congenital disorder characterized by uncontrolled proliferation and infiltration of activated lymphocytes and histiocytes, secreting high amounts of inflammatory cytokines; this may affect multiple organs including liver, spleen, lymph nodes, bone marrow, and central nervous system (CNS; Janka, Eur J Pediatr 166:95-109, 1).

OBJECTIVE

The objective of this study is to describe the characteristics of the encephalopathy and to correlate the neuroradiological findings with the clinical symptoms and the treatment response in a child with FHL type 3 studied by total body computed tomography and by brain magnetic resonance (MR) and MR spectroscopy.

RESULTS

VF, a 14-month-old female, developed a full-blown FHL, with facial nerve palsy as the only CNS complication. Brain MR imaging showed several focal areas of pathological signal in the subcortical and periventricular white matter, left thalamus, cerebellum, and brain stem. Proton MR spectroscopy also demonstrated no elevated peak of Cho, no lactate peak, and elevated glutamine/glutamate complex. Moreover, an elevated N-acetyl aspartate (NAA) peak was detected. The follow-up MR study after hematopoietic stem cells transplantation showed a dramatic reduction of the lesions and normalization of the metabolic pattern at spectroscopy.

CONCLUSION

Brain lesions and metabolic alterations documented by MR and spectroscopy during active FHL reverted during disease control achieved by therapy.

Diagnostic challenges in a child with familial hemophagocytic lymphohistiocytosis type 3 (FHLH3) presenting with fulminant neurological disease

BACKGROUND

Familial hemophagocytic lymphohistiocytosis (FHLH) is an autosomal recessively inherited multisystem disease characterized by fever, rash, splenomegaly, cytopenias, and variable central nervous system (CNS) manifestations.

CASE HISTORY

We report the case of a 3-year-old boy who presented with splenomegaly and normocytic anemia 4 months after returning to the US from a region endemic for Leishmania infection. The child later developed progressive neurological impairment and had radiologic evidence of widespread demyelinating disease. Gene studies showed homozygosity for a mutation at Munc13-4, confirming FHLH type 3.

DISCUSSION

The diagnostic uncertainty that accompanies FHLH was compounded by our patient's travel history and CNS disease mimicking acute disseminated encephalomyelitis (ADEM). Diagnostic criteria for hemophagocytic lymphohistiocytosis were not consistently met, despite aggressive disease.

CONCLUSIONS

FHLH may present with fulminant demyelinating disease, mimicking ADEM, and without necessarily meeting previously defined clinical and laboratory criteria. We strongly recommend expeditious molecular testing and genetic counseling for FHLH mutations in cases of undiagnosed inflammatory CNS disease in the pediatric population.

The role of the initial bone marrow aspirate in the diagnosis of hemophagocytic lymphohistiocytosis

BACKGROUND

The identification of hemophagocytosis (HPC) in tissue or bone marrow (BM) represents only one of 5/8 criteria needed for the diagnosis of hemophagocytic lymphohistiocytosis (HLH). Yet, confirmation of HPC in bone marrow aspirates (BMA) is often relied upon to make therapeutic decisions. There is no standardized reporting criteria for the definition of "positive" BMA, and likely differs between institutions. The purpose of this study was to quantify the number of HPC in the initial BMA in patients diagnosed with HLH at our institution.

PROCEDURE

Patient charts were retrospectively reviewed. Numbers of HPC were counted per 500 nucleated cells in initial BMA.

RESULTS

Fifty-eight percent of patients had at least one HPC per 500 nucleated cells. Median number of HPC per 500 cells was 1 (0-12). Median time from initial BMA to HLH diagnosis was 0 days (-3 to 11), suggesting that HLH diagnosis was made regardless of the results of this initial BMA.

CONCLUSION

The number of HPC at initial BMA is often low and variable, confirming that a BMA lacking HPC does not rule out the diagnosis of HLH, and a negative initial BMA should not delay therapy. We recommend that the BMA report should document negative as well as any positive findings of HPC.

Familial and acquired hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition of severe hyperinflammation caused by the uncontrolled proliferation of activated lymphocytes and histiocytes secreting high amounts of inflammatory cytokines. Cardinal signs and symptoms are prolonged fever, hepatosplenomegaly and pancytopenia. Characteristic biochemical markers include elevated triglycerides, ferritin and low fibrinogen. HLH occurs on the basis of various inherited or acquired immune deficiencies. Impaired function of natural killer (NK) cells and cytotoxic T-cells (CTL) is shared by all forms of HLH. Genetic HLH occurs in familial forms (FHLH) in which HLH is the primary and only manifestation, and in association with the immune deficiencies Chédiak-Higashi syndrome 1 (CHS 1), Griscelli syndrome 2 (GS 2) and x-linked lymphoproliferative syndrome (XLP), in which HLH is a sporadic event. Most patients with acquired HLH have no known underlying immune deficiency. Both acquired and genetic forms are triggered by infections, mostly viral, or other stimuli. HLH also occurs as a complication of rheumatic diseases (macrophage activation syndrome) and of malignancies. Several genetic defects causing FHLH have recently been discovered and have elucidated the pathophysiology of HLH. The immediate aim of therapy in genetic and acquired HLH is suppression of the severe hyperinflammation, which can be achieved with immunosuppressive/immunomodulatary agents and cytostatic drugs. Patients with genetic forms have to undergo stem cell transplantation to exchange the defective immune system with normally functioning immune effector cells. In conclusion, awareness of the clinical symptoms and of the diagnostic criteria of HLH is crucial in order not to overlook HLH and to start life-saving therapy in time.

Macrophage activation syndrome: characteristic findings on liver biopsy illustrating the key role of activated, IFN-gamma-producing lymphocytes and IL-6- and TNF-alpha-producing macrophages

Macrophage activation syndrome (MAS) is a rare and potentially fatal disorder, thought to result from uncontrolled activation and proliferation of T cells and excessive activation of macrophages. The term MAS designates a clinicopathologic entity that occurs in different hemophagocytic syndromes (HSs). Primary hemophagocytic lymphohistiocytosis (HLH) is recognized to have an immunogenetic basis, but in the secondary HS (also referred to as secondary HLH), the cause is unknown. The pathogenesis of the accelerated disease phase typical of MAS remains incompletely understood. This report describes the immunohistochemical findings on liver tissues from 5 children, each of whom presented with MAS in the context of a different type of HS. The data provide direct evidence for the involvement of activated CD8(+) lymphocytes through the production of interferon-gamma and of macrophages through hemophagocytosis and production of interleukin 6 and tumor necrosis factor-alpha, and underscore the view that MAS in different HSs share a common effector pathway.

Identical twin brothers concordant for Langerhans' cell histiocytosis and discordant for Epstein-Barr virus-associated haemophagocytic syndrome

We report on identical twin brothers, one of whom presented at 14 months of age with fever and clinical, laboratory and histological evidence of Epstein-Barr virus-associated haemophagocytic syndrome (EBV-AHS) and 4 months later with typical signs and symptoms of Langerhans' cell histiocytosis (LCH). The other twin, without previous symptoms, also displayed at that time LCH associated with signs of recent EBV infection, but without symptoms of haemophagocytic syndrome. No mutation in the SH2D1A gene, as observed in X-linked lymphoproliferative disease, or in the perforin gene as observed in some cases of hereditary haemophagocytic syndrome, was found.

CONCLUSION

the occurrence of haemophagocytic syndrome and Langerhans' cell histiocytosis, although genetically based, can be triggered by environmental agents and viruses, in particular Epstein-Barr virus.

Multifactorial risk analysis of bone marrow histiocytic hyperplasia with hemophagocytosis in critically ill medical patients--a postmortem clinicopathologic analysis

OBJECTIVE

Systematic studies of the prevalence and risk factors of histiocytic hyperplasia with hemophagocytosis (HHH) in critically ill patients are lacking. The aim of our study was a) to determine the frequency and intensity of HHH in the bone marrow of patients who died on the medical intensive care unit; b) to analyze morphologic bone marrow changes; and c) to identify possible risk factors and their interactions in the pathogenesis of HHH.

DESIGN

A retrospective observational analysis of clinical data and autopsy findings including histologic and immunohistological analysis of bone marrow to characterize cellularity, siderosis, hemophagocytosis, and T-cell infiltrates.

SETTING

The medical intensive care unit of a university hospital.

PATIENTS

Patients were 107 consecutive patients who died and underwent autopsy.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

HHH was identified in 69 of the 107 patients (64.5%). Moderate to severe HHH was present in 35 of the 107 bone marrows. Univariate risk factor analysis showed that HHH was associated with various intrinsic and extrinsic factors. However, multivariate analysis identified the intensity of therapeutic interventions--represented by the Therapeutic Intervention Scoring System--as the only positive, and cardiovascular disease as the only significant negative, predictor of HHH (p <.05). Routine laboratory tests were of no value in predicting the presence of HHH. The intensity of HHH correlated significantly with siderosis and T-cell infiltrates (p <.05) but not with bone marrow cellularity.

CONCLUSIONS

HHH is common in medical intensive care unit nonsurvivors. Treatment intensity and a noncardiovascular cause of death are predictors of HHH. Sepsis and blood transfusion may have a synergistic effect on the triggering of HHH. HHH in bone marrow is associated with enhanced T-cell infiltrates, suggesting that T cells may play an important role in its mediation.

Hemophagocytic syndrome after living-related liver transplantation

Hemophagocytic syndrome (HPS) is a life-threatening hematological disorder in immunocompromised patients. Although the number of patients with HPS following liver transplantation is scarce the outcome is usually fatal. We report a patient who developed HPS following living-related liver transplantation (LRLT) and was treated successfully by a combination of intravenous (IV) immunoglobulin (Ig) and granulocyte colony-stimulating factor (GCSF).

EBV associated hemophagocytic syndrome accompanied by central pontine myelinolysis

The development of central pontine myelinolysis (CPM) has rarely been reported in association with hemophagocytic syndromes (HPS). Here we report a unique case of Epstein-Barr Virus (EBV)-related HPS which was accompanied with CPM. A 72-year-old man who had no significant medical history was admitted to our hospital due to high fever and progressing dysphasia and dysarthria. Physical examination revealed anisocoria of the right pupil, fixed reaction to light, and paralysis of the left vagus nerves. Magnetic resonance imaging revealed low signal intensity on T1-weighted images and high signal intensity T2-weighted images in the patient's central midpontine lesion. Initial work-up showed anemia and thrombocytopenia with elevated levels of serum ferritin, lactate dehydrogenase, and soluble IL-2 receptor. Bone marrow aspiration revealed hemophagocytosis. The EBV genome was detected in the peripheral blood using the polymerase chain reaction method. He was diagnosed as having EBV-related HPS and CPM. Despite intensive treatment with methylpredonisolone, immunoglobulin, and etoposide, he died due to progressive disease and fungal septicemia. The etiology and relation between CPM and HPS are discussed.

[Hemophagocytic syndrome associated with neutropenia after chemotherapy]

MATERIAL AND METHODS

This retrospective study reports 15 cases of hemophagocytic syndrome in children treated in our department during a eight-year period.

RESULTS

Underlying diseases were acute lymphoblastic leukemia (n = 8) acute myeloblastic leukemia (n = 6) and Burkitt lymphoma (n = 1). Hemophagocytic syndrome was suspected after chemotherapy, in case of an unusual prolonged febrile neutropenia (n = 14) or isolated thrombocytopenia (n = 1). That fever was associated with cutaneous, pulmonary, hematologic, digestive and cardiac signs. Biological disorders included hypoprotidemia, hyponatremia, increased liver enzymes and fibrinopenia. Thrombocytopenia was observed in all patients and was associated with neutropenia for 14 of them. Diagnosis of hemophagocytic syndrome was always confirmed by bone marrow aspiration (infiltration with activated macrophages). Infection was documented in eight children. The treatment of hemophagocytic syndrome relied on steroids and resolution of symptoms occurred within three days of therapy. No recurrence of hemophagocytic syndrome was observed with a median follow up of two years and a half.

CONCLUSION

Such complication should be suspected in cases of prolonged febrile neutropenia and/or thrombocytopenia, and confirmed by bone marrow aspiration. Indeed, steroid therapy is effective and chemotherapy can be then pursued.

Splenectomy in haemophagocytic lymphohistiocytosis: report of histopathological changes with CD19+ B-cell depletion and therapeutic results

The pathogenesis of haemophagocytic lymphohistiocytosis (HLH) in children without a known familial pattern of inheritance is often difficult to establish. Splenic enlargement, one of the main clinical findings in this disorder, has led to the use of splenectomy for uncontrollable coagulopathy, persistent cytopenia or both. This procedure is also thought to be a useful tool in making a differential diagnosis in cases of the immunochemotherapy-resistant HLH. We report here five cases of splenectomized childhood HLH, in which subsets of mononuclear spleen cells were analysed either by flow cytometry or immunohistochemistry, and the results were compared with those from cases of hereditary spherocytosis (controls). There was a statistically significant depletion of CD19+ B cells in the HLH cases (3.8 +/- 3.2% vs. 52.6 +/- 4.5%, P < 0. 0001) associated with an increase of T cells in three cases and of natural killer cells in another. The histopathological findings included atrophic white pulps, B-cell depletion with fibrosis and haemosiderosis in all five cases. Despite temporary therapeutic benefits, three of the HLH patients had a rapidly deteriorating post-splenectomy course and all three eventually died. These results demonstrate striking depletion of B cells in the enlarged spleens of children with HLH, which may be an intrinsic feature of HLH pathogenesis. Further study is needed to establish the therapeutic value of splenectomy in this disease.

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.

Malignant histiocytosis. Histologic, cytochemical, chromosomal, and molecular data with a nosologic discussion

Although myelomonoblastic leukemia is thought to originate from a malignant transformation of the stem cell of the mononuclear phagocyte system, malignant histiocytosis (MH) is classically assumed to represent a malignant change of the terminal and fixed elements of this system. Indeed, MH is characterized by the proliferation of large, clear, pleomorphic, "histiocytic-like" HLADR and CD30+ cells resulting in a nodal and extranodal disseminated neoplasm affecting preferentially and severely children and young adults. Although there is broad agreement on the clinicopathologic presentation of this condition, there is currently quite a controversy over the T-lymphoid or histiocytic origin of the proliferative cells that results in a nosologic discussion between the anaplastic large cell lymphoma (ALCL) advocates and the MH supporters. This article has dealt mainly with this nosologic discussion and with the contributions provided by the investigations performed on MH permanent cell lines. These in vitro studies have demonstrated that the proliferation is characterized by a unique chromosomal abnormality, the 5q35bp usually associated with a t(2;5) translocation generating a fusion gene NPM/ALK and the subsequent translation of p80 protein. Although it is known that no single chromosomal abnormality is strictly restricted to a cell lineage, this 5q35bp and associated translocations seem today to represent the hallmark for this condition. In view of these chromosomal aberrations, the CD30+ ALCLs represent a heterogeneous group because 15% to 50% express the NPM/ALK fusion gene. In addition, these in vitro investigations have shown that 5q35bp proliferative cells are glass-adherent, can develop an immunodependent phagocytosis, and are able to reduce NBT and produce TNF-alpha. More significantly, they express constitutively the c-fms (the receptor of the macrophage growth factor) and, under TPA stimulation, are able to modulate the expression of this receptor and its ligand, as well as TNF-alpha and IL-1. None of these cell lines express CD3, but several express CD68 and CD71. In contrast, genomic investigations have shown the underlying existence of monoallelic and even biallelic gene rearrangements for TCR beta and IgJH. In view of these discrepancies between the genomic and phenotypic features of these cells, the histogenetic debate should remain open but must take into account these new chromosomal and molecular data.

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.

Ocular involvement in familial erythrophagocytic lymphohistiocytosis

BACKGROUND

Familial erythrophagocytic lymphohistiocytosis (FEL), a rare, rapidly fatal childhood disorder, is characterized by intermittent fevers, hepatosplenomegaly, cytopenia, hypercytokinemia and lymphohistiocytic infiltration with erythrophagocytosis involving multiple organs. We report the clinical and histological features of two infants with FEL and emphasize the ocular findings.

METHODS

Microscopic examination of formalin-fixed, paraffin-embedded autopsy material was performed. Immunohistochemical studies were performed in case 1.

RESULTS

The first patient presented with clinical and laboratory features and a family history consistent with FEL, and a liver biopsy revealed a lymphohistiocytic infiltrate with erythrophagocytosis consistent with FEL. A deceased brother had been diagnosed with FEL. Autopsy showed widely disseminated lymphohistiocytic infiltrates affecting the liver, spleen, bone marrow, lungs, kidneys and brain. Histologic examination of both eyes disclosed a prominent lymphohistiocytic infiltrate of the optic nerve with destruction of nerve fiber bundles as well as milder infiltrates in the choroid, scleral canals, perineural areas in the orbit and the optic nerve head perivascularly. The second patient also had the typical clinical, laboratory and autopsy findings with similar involvement of most organs, including extensive infiltration of the spleen and bone marrow. Histologic examination of one eye revealed marked lymphohistiocytic infiltration of the entire choroid as well as milder infiltration in the trabecular meshwork, iris, ciliary body, optic nerve, meninges and around the central retinal vein in the optic nerve.

CONCLUSION

The findings of this study further define the ocular pathologic features of FEL, which are a part of a generalized, multiorgan disseminated disease.

Frequency and Severity of Central Nervous System Lesions in Hemophagocytic Lymphohistiocytosis

We have retrospectively assessed the neurological manifestations in 34 patients with hemophagocytic lymphohistiocytosis (HLH) in a single center. Clinical, radiological, and cerebrospinal fluid (CSF ) cytology data were analyzed according to treatment modalities. Twenty-five patients (73%) had evidence of central nervous system (CNS) disease at time of diagnosis, stressing the frequency of CNS involvement early in the time course of HLH. Four additional patients who did not have initial CNS disease, who did not die early from HLH complications, and who were not transplanted, also developed a specific CNS disease. Therefore, all surviving and nontransplanted patients had CNS involvement. Initially, CNS manifestations consisted of isolated lymphocytic meningitis in 20 patients and meningitis with clinical and radiological neurological symptoms in nine patients. For these nine patients, neurological symptoms consisted of seizures, coma, brain stem symptoms, or ataxia. The outcome of patients treated by systemic and intrathecal chemotherapy and/or immunosuppression exclusively (n = 16) was poor, as all died following occurrence of multiple relapses or CNS disease progression in most cases. Bone marrow transplantation (BMT) from either an HLA identical sibling (n = 6) or haplo identical parent (n = 3) was performed in nine patients, once first remission of CNS and systemic disease was achieved. Seven are long-term survivors including three who received an HLA partially identical marrow. All seven are off treatment with normal neurological function and cognitive development. In four other patients, BMT performed following CNS relapses was unsuccessful. Given the frequency and the poor outcome of CNS disease in HLH, BMT appears, therefore, to be the only available treatment procedure that is capable of preventing HLH CNS disease progression and that can result in cure when performed early enough after remission induction.

Histopathology of the liver in histiocytosis syndromes

Liver biopsies were studied in 47 cases representing various histiocytosis syndromes. These included 32 cases of hemophagocytic syndrome, 11 cases of Langerhans cell histiocysis (LCH), and 4 cases of other histiocytic disorders. All cases of hemophagocytic syndrome, except one with cytomegalovirus infection, displayed portal lymphohistiocytic infiltrates dominated by T lymphocytes. Activation of the hepatic mononuclear phagocytic system (MPS), evidenced by enlarged von Kupffer cells, some of which were hemophagocytic, was seen in 28 cases of hemophagocytic syndrome. Endothelial enlargement, minor degrees of hepatocellular degeneration, and steatosis were also noted. Ten of the 11 cases of LCH also showed activation of the MPS. It was the only lesion in two biopsies. Seven cases demonstrated nonspecific "triaditis." In three this was associated with cholangiocentric and random acinar histiocytic lesions. Evidence of activation of the MPS was also observed in both cases of Rosai-Dorfman disease and was accompanied by acinar histiocytic lesions in one and triaditis in the other. Likewise, both cases of juvenile xanthogranuloma showed activation of the MPS and focal granulomatous lesions. It is concluded that activation of the MPS is a common feature of liver disease in histiocytosis syndromes and that hepatic enlargement may be the result of this process instead of, or in addition to, the liver lesions known to be featured in these disorders. Hepatic lesions of the various histiocytosis syndromes resemble typical lesions in other sites and, in some instances, are accompanied by nonspecific changes. These nonspecific changes may occur in the absence of lesions that are diagnostic or typical of the particular histiocytosis syndrome. The location and character of hepatic lesions are important factors in the significance of liver involvement.

Infection-associated hemophagocytic syndrome complicated by infectious lymphoproliferation: a case report

The case of a 7-year-old boy with virus-associated hemophagocytic syndrome (VAHS) and serologically proven parvovirus B-19 infection is described. The patient with VAHS presented with fever, hepatosplenomegaly, pancytopenia, and hyperlipidemia type IV. After induction therapy with VP-16 and prednisone, partial remission was achieved. Despite maintenance therapy, reinductions, and the addition of cyclosporine A for 3 months, several relapses occurred. The therapy was stopped because of life-threatening complications (Klebsiella sepsis, neutropenic enterocolitis, and stercoral peritonitis). The complications were treated successfully. The patient status was stabilized after splenectomy. However, hepatomegaly progressed slowly and the hyperlipidemia endured. Ten months after the diagnosis leukocytosis with absolute T lymphocytosis appeared. Reactivation of VAHS was suspected and intravenous immunoglobin and then antilymphocyte immunoglobulin ALG therapy were started. The resultant decrease in leukocytosis was prompt, but lymphopenia did not occur. Virostatic treatment with foscarnet was introduced based on human herpesvirus-6 seroconversion. Twenty-six months after the diagnosis, the patient is well, without any sign of VAHS or lymphoproliferation.

Histiocytoses

Childhood histiocytoses are a rare and diverse group of histiocytic disorders. This review will focus on clinical, pathological and immunopathological features of these syndromes. The pathogenesis of Langerhans' cell histiocytosis or class I histiocytosis, a proliferative disorder of the Langerhans' cell, remains enigmatic. Approaches to treatment are as varied as the clinical presentations, ranging from a fatal leukaemia-like disorder to solitary lytic lesions of bone. Recent findings indicate that Langerhans' cell histiocytosis is a clonal histiocytic disease. The two major class II histiocytoses are familial erythrophagocytic lymphohistiocytosis and the reactive haemophagocytic syndromes. The clinicopathological similarities between these two entities suggest that they share a common immunological feature in which uncontrolled cytokine release from activated T-cells leads macrophages to a haemophagocytosing state.

Clonal and non-clonal karyotypically abnormal cells in haemophagocytic lymphohistiocytosis

We studied chromosomes in bone marrow (BM) or peripheral blood cells of nine patients with haemophagocytic lymphohistiocytosis (HLH); three of them had a family history of HLH and four others underwent concurrent Epstein-Barr virus (EBV) infection. In addition to a large population of normal mitotic cells, karyotypically abnormal clonal cells were found in two patients, abnormal clonal cells and a nonclonal (single) abnormal cell in one, and nonclonal abnormal cells in three. All the six patients with chromosome abnormalities died of progressive disease; one of them also had EBV infection and EBV-associated clonal proliferation. Two of three patients with EBV infection and only normal mitotic cells in BM completely recovered from the disease. Although HLH did not show histological and/or haematological evidence of a neoplastic disease, clonal chromosome abnormalities and the fatal clinical outcome found in some of the patients suggest that the disease may be heterogenous and include malignancy. HLH patients with karyotypically abnormal clonal cells in BM should warrant more intensive chemotherapy than that presently being applied to them and should be considered as candidates for BM transplantation.

Griscelli syndrome: report of three cases

The clinical features of three children with Griscelli syndrome and autopsy findings of two are presented. The patients were 5 years, 9 months, and 3 months old, respectively. Clinical features included partial albinism, hepatosplenomegaly, and various neurological symptoms. Light and electron microscopic studies of the skin were compatible with Griscelli syndrome. Postmortem examination of the viscera and central nervous system revealed lymphohistiocytic infiltration with erythrophagocytosis. Bilateral diffuse involvement of the central nervous system, cranial nerve, and spinal cord was detected in both cases.

Non-familial hemophagocytic lymphohistiocytosis

A case of non-familial hemophagocytic lymphohistiocytosis (HLH) is described. The patient had a chronic course being alive and doing relatively well 3 years since onset. The specific pathological features of this disorder are discussed with emphasis on the fact that a remarkable loss of lymph node structure is sustained by a mature lymphohistiocytic infiltrate. Erythrophagocytosis is assessed as an important but not specific finding. Lymphocyte depletion is an important feature of the lesion. The presence of overlapping features in HLH, infection-associated hemophagocytic syndrome (IAHS) and X-linked recessive lymphoproliferative syndrome (XLS) is emphasized.

Unusual immunophenotype displayed by histiocytes in haemophagocytic lymphohistiocystosis

Extensive immunophenotypic studies in a 2 1/2 month old girl with haemophagocytic lymphohistiocytosis were performed to characterise the proliferating histiocytes of the disease. The cells strongly expressed conventional macrophage antigens, but unexpectedly, there was a dissociated expression of the CD1a antigen (reacting with the monoclonal antibody NA1/34 but not with OKT6) and intracellular S-100 protein by the haemophagocytic lymphohistiocytosis histiocytes. These findings indicate that there is a "hybrid" phenotype between the two main arms of the mononuclear phagocyte system--namely, Langerhans' cells and phagocytic macrophages.