Reactive histiocytic hyperplasia with hemophagocytosis in hematopoietic organs: a reevaluation of the benign hemophagocytic proliferations

Predicting Secondary Hemophagocytic Lymphohistiocytosis in Adult Patients with Scrub Typhus and Its Prognostic Significance

Objective

Secondary hemophagocytic lymphohistiocytosis (sHLH) is an increasingly recognized complication in patients with scrub typhus, potentially contributing to substantial mortality despite appropriate antibiotic treatment. This study aims to determine the prevalence and prognosis of sHLH and identify diagnostic factors in adult patients with scrub typhus in North India.

Methods

This prospective cohort study was conducted at PGIMER, Chandigarh, from August 2021 to November 2023. sHLH was defined as an HScore of 200 or above. The diagnostic performance of biomarkers such as ferritin, fibrinogen, triglycerides, and C-reactive protein was assessed through receiver operating characteristic curve analysis, evaluating area under the curve (AUC), sensitivity, and specificity.

Results

Out of 150 patients (mean age 39 years, 54% female), 28 (18.7%) were diagnosed with sHLH. Those presenting with high-grade fever, seizures, high pulse rate, hepatomegaly, splenomegaly, cytopenia, and significant hepatic dysfunction were more likely to have sHLH. Ferritin demonstrated the highest diagnostic utility (AUC 0.83), compared to fibrinogen (AUC 0.72), triglyceride (AUC 0.67), and C-reactive protein (AUC 0.69). The optimal cutoff for ferritin was 2000 ng/mL, with a sensitivity of 90% and a specificity of 66%. Higher ferritin thresholds (6000 ng/mL and 10000 ng/mL) increased specificity to 88% and 95%, respectively. Patients with sHLH often presented with multi-organ failure, necessitating mechanical ventilation and vasopressor support. In-hospital mortality was significantly higher in sHLH patients than in those without (21.4% vs 6.6%, p = 0.025).

Conclusion

Early detection of sHLH using the HScore and ferritin significantly influences the management of scrub typhus, underscoring the necessity for tailored therapeutic strategies to improve patient outcomes.

How to cite this article

Selvam S, Tuli A, Yuvasai KP, Saini S, Erla SR, Kaur J, et al. Predicting Secondary Hemophagocytic Lymphohistiocytosis in Adult Patients with Scrub Typhus and Its Prognostic Significance. Indian J Crit Care Med 2024;28(9):823-831.

Cytokine Storm and Sepsis-Induced Multiple Organ Dysfunction Syndrome

There is extensive overlap of clinical features among familial or primary HLH (pHLH), reactive or secondary hemophagocytic lymphohistiocytosis (sHLH) [including macrophage activation syndrome (MAS) related to rheumatic diseases], and hyperferritinemic sepsis-induced multiple organ dysfunction syndrome (MODS); however, the distinctive pathobiology that causes hyperinflammatory process in each condition requires careful considerations for therapeutic decision-making. pHLH is defined by five or more of eight HLH-2004 criteria [1], where genetic impairment of natural killer (NK) cells or CD8+ cytolytic T cells results in interferon gamma (IFN-γ)-induced hyperinflammation regardless of triggering factors. Cytolytic treatments (e.g., etoposide) or anti-IFN-γ monoclonal antibody (emapalumab) has been effectively used to bridge the affected patients to hematopoietic stem cell transplant. Secondary forms of HLH also have normal NK cell number with decreased cytolytic function of varying degrees depending on the underlying and triggering factors. Although etoposide was uniformly used in sHLH/MAS in the past, the treatment strategy in different types of sHLH/MAS is increasingly streamlined to reflect the triggering/predisposing conditions, severity/progression, and comorbidities. Accordingly, in hyperferritinemic sepsis, the combination of hepatobiliary dysfunction (HBD) and disseminated intravascular coagulation (DIC) reflects reticuloendothelial system dysfunction and defines sepsis-associated MAS. It is demonstrated that as the innate immune response to infectious organism prolongs, it results in reduction in T cells and NK cells with subsequent lymphopenia even though normal cytolytic activity continues (Figs. 30.1, 30.2, 30.3, and 30.4). These changes allow free hemoglobin and pathogens to stimulate inflammasome activation in the absence of interferon-γ (IFN-γ) production that often responds to source control, intravenous immunoglobulin (IVIg), plasma exchange, and interleukin 1 receptor antagonist (IL-1Ra), similar to non-EBV, infection-induced HLH.

Hyperferritinemic sepsis, macrophage activation syndrome, and mortality in a pediatric research network: a causal inference analysis

BACKGROUND

One of five global deaths are attributable to sepsis. Hyperferritinemic sepsis (> 500 ng/mL) is associated with increased mortality in single-center studies. Our pediatric research network's objective was to obtain rationale for designing anti-inflammatory clinical trials targeting hyperferritinemic sepsis.

METHODS

We assessed differences in 32 cytokines, immune depression (low whole blood ex vivo TNF response to endotoxin) and thrombotic microangiopathy (low ADAMTS13 activity) biomarkers, seven viral DNAemias, and macrophage activation syndrome (MAS) defined by combined hepatobiliary dysfunction and disseminated intravascular coagulation, and mortality in 117 children with hyperferritinemic sepsis (ferritin level > 500 ng/mL) compared to 280 children with sepsis without hyperferritinemia. Causal inference analysis of these 41 variables, MAS, and mortality was performed.

RESULTS

Mortality was increased in children with hyperferritinemic sepsis (27/117, 23% vs 16/280, 5.7%; Odds Ratio = 4.85, 95% CI [2.55-9.60]; z = 4.728; P-value < 0.0001). Hyperferritinemic sepsis had higher C-reactive protein, sCD163, IL-22, IL-18, IL-18 binding protein, MIG/CXCL9, IL-1β, IL-6, IL-8, IL-10, IL-17a, IFN-γ, IP10/CXCL10, MCP-1/CCL2, MIP-1α, MIP-1β, TNF, MCP-3, IL-2RA (sCD25), IL-16, M-CSF, and SCF levels; lower ADAMTS13 activity, sFasL, whole blood ex vivo TNF response to endotoxin, and TRAIL levels; more Adenovirus, BK virus, and multiple virus DNAemias; and more MAS (P-value < 0.05). Among these variables, only MCP-1/CCL2 (the monocyte chemoattractant protein), MAS, and ferritin levels were directly causally associated with mortality. MCP-1/CCL2 and hyperferritinemia showed direct causal association with depressed ex vivo whole blood TNF response to endotoxin. MCP-1/CCL2 was a mediator of MAS. MCP-1/CCL2 and MAS were mediators of hyperferritinemia.

CONCLUSIONS

These findings establish hyperferritinemic sepsis as a high-risk condition characterized by increased cytokinemia, viral DNAemia, thrombotic microangiopathy, immune depression, macrophage activation syndrome, and death. The causal analysis provides rationale for designing anti-inflammatory trials that reduce macrophage activation to improve survival and enhance infection clearance in pediatric hyperferritinemic sepsis.

Random Skin Biopsy Is a Useful Procedure in the Evaluation of Hemophagocytic Lymphohistiocytosis: A Case Report and Review of Literature

ABSTRACT

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening syndrome, characterized by aberrant activation of T lymphocytes and macrophages leading to hypercytokinemia. HLH can be familial or a result of various secondary etiologies. We present a case of a 46-year-old woman with a past medical history of multiple sclerosis on rituximab who presented as a transfer from an outside hospital with numerous clinical abnormalities including recurrent episodes of fever of unknown origin for 3 weeks, persistent leukocytosis, hypertriglyceridemia, and steatohepatitis. Given the uncertain nature of her illness, she underwent a random skin biopsy from the abdominal region to exclude hematolymphoid malignancy. Histopathology revealed a brisk histiocytic rich dermal infiltrate accompanied by perivascular lymphocytic infiltrate. The histiocytes were enlarged and positive for muraminadase and CD68 stains exhibiting hemophagocytosis focally. As per the HLH-2004 protocol, our patient met the diagnostic criteria of HLH. Concurrent bone marrow biopsy revealed similar rare hemophagocytosis. Cytogenetics and molecular studies were negative, supporting secondary HLH.

Diagnosing Hemophagocytic Lymphohistiocytosis with Machine Learning: A Proof of Concept

Hemophagocytic lymphohistiocytosis is a hyperinflammatory syndrome characterized by uncontrolled activation of immune cells and mediators. Two diagnostic tools are widely used in clinical practice: the HLH-2004 criteria and the Hscore. Despite their good diagnostic performance, these scores were constructed after a selection of variables based on expert consensus. We propose here a machine learning approach to build a classification model for HLH in a cohort of patients selected by glycosylated ferritin dosage in our tertiary center in Lyon, France. On a dataset of 207 adult patients with 26 variables, our model showed good overall diagnostic performances with a sensitivity of 71.4% and high specificity, and positive and negative predictive values which were 100%, 100%, and 96.9%, respectively. Although generalization is difficult on a selected population, this is the first study to date to provide a machine-learning model for HLH detection. Further studies will be required to improve the machine learning model performances with a large number of HLH cases and with appropriate controls.

Secondary haemophagocytic lymphohistiocytosis in COVID-19: correlation of the autopsy findings of bone marrow haemophagocytosis with HScore

BACKGROUND

Secondary haemophagocytic lymphohistiocytosis (sHLH) is characterised by a hyper activation of immune system that leads to multiorgan failure. It is suggested that excessive immune response in patients with COVID-19 could mimic this syndrome. Some COVID-19 autopsy studies have revealed the presence of haemophagocytosis images in bone marrow, raising the possibility, along with HScore parameters, of sHLH.

AIM

Our objective is to ascertain the existence of sHLH in some patients with severe COVID-19.

METHODS

We report the autopsy histological findings of 16 patients with COVID-19, focusing on the presence of haemophagocytosis in bone marrow, obtained from rib squeeze and integrating these findings with HScore parameters. CD68 immunohistochemical stains were used to highlight histiocytes and haemophagocytic cells. Clinical evolution and laboratory parameters of patients were collected from electronic clinical records.

RESULTS

Eleven patients (68.7%) displayed moderate histiocytic hyperplasia with haemophagocytosis (HHH) in bone marrow, three patients (18.7%) displayed severe HHH and the remainder were mild. All HScore parameters were collected in 10 patients (62.5%). Among the patients in which all parameters were evaluable, eight patients (80%) had an HScore >169. sHLH was not clinically suspected in any case.

CONCLUSIONS

Our results support the recommendation of some authors to use the HScore in patients with severe COVID-19 in order to identify those who could benefit from immunosuppressive therapies. The presence of haemophagocytosis in bone marrow tissue, despite not being a specific finding, has proved to be a very useful tool in our study to identify these patients.

Correlation of haemophagocytosis with clinical criteria of haemophagocytic lymphohistiocytosis and recommendations for bone marrow reporting

Haemophagocytic lymphohistiocytosis (HLH) is a rare condition resulting from a dysregulated inflammatory response. Currently there are no guidelines on the reporting of haemophagocytosis on bone marrow biopsy (BM) and lack of evidence on correlation between haemophagocytosis with the clinical diagnostic criteria for HLH. We aimed to assess if the amount of haemophagocytosis identified in the BM correlates with HLH-2004 criteria. Secondary aims were to evaluate inter-observer variability in reporting haemophagocytosis, and to formulate recommendations for screening in bone marrow specimens. A retrospective review of bone marrow biopsies from adult patients under investigation for HLH was undertaken independently by two haematopathologists who were blinded to the original biopsy report. The average number of actively haemophagocytic cells in each slide were quantified. Cases with discordance pertaining to the degree of haemophagocytosis were reviewed by both assessors to reach a consensus. Sixty-two specimens from 59 patients were available for assessment. An underlying haematological condition was identified in 34 cases (58%). There was a significant association between the amount of haemophagocytosis identified on the aspirate samples and the number of HLH-2004 criteria met (p<0.0001). In patients where haemophagocytosis was present (n=31), there was a correlation between the amount of haemophagocytosis and ferritin (p=0.041). Based on our review, we have made recommendations for the reporting of BM haemophagocytosis. Our findings indicate that the amount of haemophagocytosis present on BM samples correlates with the number of HLH-2004 criteria. We found marked interobserver variability which we anticipate can be rectified with our recommendations for reporting.

Secondary Hemophagocytic Lymphohistiocytosis in Post-COVID-19 Patients: A Report of Two Cases

Hemophagocytic lymphohistiocytosis (HLH) is a disease that can affect both children and adults. HLH can be categorized as primary or secondary. Secondary HLH (sHLH) may be secondary to various viral infections. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus infection is a pandemic with multi-system involvement. HLH in COVID-19 positive patients is a recognized entity. However, in post-COVID-19 patients who have recovered and are negative by serological tests and reverse transcription-polymerase chain reaction test may present with sHLH due to dysregulation of the immune system. We highlight this unusual finding of post-COVID-19 sHLH in two cases, who were diagnosed by the new revised H-score.

Bone marrow haemophagocytosis indicates severe infection with severe acute respiratory syndrome coronavirus 2

AIMS

Haemophagocytosis in the bone marrow of patients who have succumbed to coronavirus disease 19 (COVID-19) has not been widely studied. The aims of the present study were to perform morphological analyses and morphometry of haemophagocytosis in the bone marrow of patients with severe COVID-19, and to correlate the findings with the clinical course of the disease.

METHODS AND RESULTS

In this single-centre study performed at the University Hospital Jena, bone marrow specimens of 15 deceased patients who had experienced a severe course of COVID-19 were sampled from the vertebral column during autopsy. Slides of the bone marrow were stained with routine stains or immunohistochemically, and further examined for haemophagocytosis by the use of light microscopy. To substantiate the morphological findings, additional slides were stained for CD163 and morphometry was performed. In all bone marrow samples, an increase in cellularity was found. Haemophagocytes with erythrophagocytosis were detected in 67% of the deceased patients. In tissues with low numbers of haemophagocytes or ill-defined haemophagocytes, an increase in iron deposits was frequently seen. Morphological findings were then correlated with several important clinical data, and the HScore (probability of having a reactive hemophagocytic syndrome) was calculated to posthumously confirm the diagnosis of secondary haemophagocytic lymphohistiocytosis. The median duration of disease and the hospitalisation time were lower in patients with haemophagocytosis (n = 10) than in patients without haemophagocytosis (n = 5). In addition, patients with haemophagocytes showed increased inflammatory parameters 2-5 days prior to death, in contrast to patients without haemophagocytes.

CONCLUSIONS

Haemophagocytosis is a common finding in the bone marrow of deceased individuals with severe COVID-19, and may indicate fatal severe acute respiratory syndrome coronavirus 2 infections.

Can we truly diagnose adult secondary hemophagocytic lymphohistiocytosis (HLH)? A critical review of current paradigms

The HLH-2004 criteria were initially conceived as inclusion criteria for a clinical trial investigating therapy for (largely primary) pediatric hemophagocytic lymphohistiocytosis (HLH). These criteria have since been extrapolated to diagnose adult secondary HLH despite their questionable generalizability. It remains unclear whether these diagnostic criteria are truly applicable among adult secondary cases, and rigorous evidence for their use among such patients is lacking. This review critically examines the utility of the HLH-2004 criteria for the diagnosis of adult secondary HLH. It is framed as a reappraisal of each of the criteria's individual components, with an assessment of the relevance of, and/or evidence regarding, each. There are clear limitations to these criteria as they apply to adult secondary HLH, however they may help guide our understanding of the disease to some extent. Some new paradigms are emerging for the diagnosis of adult secondary HLH, however these too are limited by the difficulties inherent in formulating specific criteria for a very non-specific syndrome, which lacks any single gold-standard diagnostic test.

Post-Transfusion Hemophagocytosis Without Hemophagocytic Lymphohistiocytosis

Hemophagocytosis refers to ingestion of hematopoietic elements or mature blood cells by another cell, typically by cells conventionally associated with phagocytic capacity. Although the finding of hemophagocytosis as a prominent feature in a patient’s bone marrow might prompt consideration of a hemophagocytic syndrome (HPS) such as hemophagocytic lymphohistiocytosis (HLH) in a clinician’s or pathologist’s differential diagnosis, this morphologic feature can be nonspecific in the absence of other clinical and laboratory features of pathologic immune activation, which is the sine qua non of HPS/HLH. We describe three patients whose clinical presentations included transfusion-dependent anemia and whose bone marrow aspirates showed unexpectedly brisk hemophagocytosis of mature red blood cells. Despite striking morphologic hemophagocytosis, no patient met criteria for diagnosis of an HPS. Transfusion-associated hemophagocytosis and hyperferritinemia must be carefully distinguished from HLH through clinical and laboratory assessment. Biomarkers of pathologic immune activation are important diagnostic aids.

Secondary Hemophagocytic Lymphohistiocytosis, Macrophage Activation Syndrome, and Hyperferritinemic Sepsis-Induced Multiple-Organ Dysfunction Syndrome in the Pediatric ICU

Children with secondary hemophagocytic lymphohistiocytosis present diagnostic and therapeutic challenges to the intensivist. Management of this condition can be facilitated with a collaborative approach among a team of intensivists, immunologists, rheumatologists, hematologists, and infectious disease specialists. Controversy over management approach commonly centers on incomplete understanding at the time of clinical presentation regarding individual patient differences in inflammation pathobiology that require different therapies. This review provides the clinician with the rationale for personalizing care for these critically ill children.

Contribution to diagnosis and treatment of bone marrow aspirate results in critically ill patients undergoing bone marrow aspiration: a retrospective study of 193 consecutive patients

Background

The purpose of the work was to assess the contribution to diagnosis and/or treatment (CDT) of bone marrow aspiration (BMA) in the critically ill patient.

Methods

The retrospective study included 193 patients. On the basis of BMA findings, contribution to diagnosis was defined by one of four previously unestablished diagnoses (maturation arrest of granulocyte precursors, hemophagocytic lymphohistiocytosis, hematological malignancy, marrow infiltration with cancer cells) and to treatment as the initiation or withdrawal of a specific treatment including the decision to forgo life-sustaining treatment (DFLST).

Results

A CDT of BMA was observed in 40/193 patients (20.7%). BMA contributed to diagnosis in 37 cases (granulocyte precursor maturation arrest, N = 10; hemophagocytic lymphohistiocytosis, N = 12; hematological malignancy, N = 15) and to treatment in 14, including three DFLSTs. In multivariate analysis, the factors associated with a CDT were hematological malignancy, cancer or non-malignant hematological abnormality known on admission, indication for BMA excluding isolated thrombocytopenia, higher pre-BMA HScore (calculated prior to BMA), and higher SOFA score with or without platelet-count SOFA subscore. In the 160 patients without hematological malignancy or cancer known on admission, non-malignant hematological abnormality known on admission, indication for BMA excluding isolated thrombocytopenia, higher pre-BMA HScore, and higher SOFA score calculated with or without platelet-count SOFA subscore were independently associated with a CDT of BMA.

Conclusion

BMA can have a significant CDT in ICU patients with or without a known hematological malignancy or cancer on admission. An HScore calculated before BMA can be a valuable tool for predicting a CDT of BMA.

Electronic supplementary material

The online version of this article (10.1186/s40560-017-0263-7) contains supplementary material, which is available to authorized users.

Newly recognized cerebral infarctions on postmortem imaging: a report of three cases with systemic infectious disease

BACKGROUND

Postmortem imaging (PMI) refers to the imaging of cadavers by computed tomography (CT) and/or magnetic resonance imaging (MRI). Three cases of cerebral infarctions that were not found during life but were newly recognized on PMI and were associated with severe systemic infections are presented.

CASE PRESENTATIONS

An 81-year-old woman with a pacemaker and slightly impaired liver function presented with fever. Imaging suggested interstitial pneumonia and an iliopsoas abscess, and blood tests showed liver dysfunction and disseminated intravascular coagulation (DIC). Despite three-agent combined therapy for tuberculosis, she died 32 days after hospitalization. PMI showed multiple fresh cerebral and cerebellar infarctions and diffuse ground-glass shadows in bilateral lungs. On autopsy, the diagnosis of miliary tuberculosis was made, and non-bacterial thrombotic endocarditis that involved the aortic valve may have caused the cerebral infarctions. A 74-year-old man on steroid therapy for systemic lupus erythematosus presented with severe anemia, melena with no obvious source, and DIC. Imaging suggested intestinal perforation. The patient was treated with antibiotics and drainage of ascites. However, he developed adult respiratory distress syndrome, worsening DIC, and renal dysfunction and died 2 months after admission. PMI showed infiltrative lung shadow, ascites, an abdominal aortic aneurysm, a wide infarction in the right parietal lobe, and multiple new cerebral infarctions. Autopsy examination showed purulent ascites, diffuse peritonitis, invasive bronchopulmonary aspergillosis, and non-bacterial thrombotic endocarditis that likely caused the cerebral infarctions. A 65-year-old man with an old pontine infarction presented with a fever and neutropenia. Despite appropriate treatment, his fever persisted. CT showed bilateral upper lobe pneumonia, pain appeared in both femoral regions, and intramuscular abscesses of both shoulders developed. His pneumonia worsened, his level of consciousness decreased, right hemiplegia developed, and he died. PMI showed a newly diagnosed cerebral infarction in the left parietal lobe. The autopsy revealed bilateral bronchopneumonia, right-sided pleuritis with effusion, an intramuscular abscess in the right thigh, and fresh multiple organ infarctions. Systemic fibrin thrombosis and DIC were also found. Postmortem cultures showed E. coli and Burkholderia cepacia.

CONCLUSION

Cerebral infarction that is newly recognized on PMI might suggest the presence of severe systemic infection.

Rapidly Fatal Hemophagocytic Lymphohistiocytosis Developing Within Six Days Following Deceased-Donor Renal Transplantation: Case Report

Hemophagocytic lymphohistiocytosis (HLH) is an often fatal hyperinflammatory syndrome that may complicate malignancy, infection, rheumatic disease, or immunosuppression. HLH after kidney transplantation is most often triggered by infection, usually Herpes viruses such as cytomegalovirus and Epstein-Barr virus (EBV). It usually occurs early after transplantation. We present a case of HLH triggered by reactivation of EBV that pursued a rapidly fatal course within 6 days of receiving a deceased-donor kidney transplant. This case serves to remind transplant clinicians to consider HLH when cytopenias and hyperinflammation are atypical for the usual post-transplantation course. We discuss pitfalls in diagnosis and suggestions for treatment in this setting.

Assessment of the HScore for reactive haemophagocytic syndrome in patients with rheumatic diseases

OBJECTIVES

Reactive haemophagocytic syndrome (RHS) is a hyperinflammatory disorder often occurring in the background of several disorders such as infections, malignancies, and rheumatic diseases. Recently, a score known as the HScore was developed for the diagnosis of RHS. In the original study, most of the patients had underlying haematological malignancy or infection and the best cut-off value for the HScore was 169 (sensitivity 93%; specificity 86%). In this study we aimed to analyse the performance of the HScore in rheumatic disease-related RHS.

METHOD

The patients with rheumatic disorders evaluated in the Departments of Rheumatology and Paediatric Rheumatology at Hacettepe University, Ankara, Turkey between 2002 and 2014 were reviewed retrospectively. The first group (n = 30) consisted of patients with RHS; the control group (n = 64) included patients with active rheumatic diseases without RHS.

RESULTS

In the RHS group, 14 (46.7%) had adult-onset Still's disease (AOSD), 10 (33.3%) systemic juvenile idiopathic arthritis (SJIA), and six (20%) systemic lupus erythematosus (SLE). The control group (n = 64) consisted of 32 (50%) AOSD, 13 (20.3%) SJIA, and 19 (29.7%) SLE patients. Applying the HScore to the RHS patients, the best cut-off value was 190.5 with a sensitivity of 96.7% and specificity of 98.4%. When we excluded the patients from the control group who had not had bone marrow aspiration (n = 23), the same cut-off (190.5) performed best (sensitivity 96.7%; specificity 97.6%). Applying the 2004 haemophagocytic lymphohistiocytosis (HLH-2004) criteria gave a sensitivity of 56.6% and a specificity of 100% in the whole study group.

CONCLUSIONS

In our study, a cut-off value for the HScore different from the original study performed better. Further studies are warranted to determine optimum cut-off values in different studies.

Postmortem CT is more accurate than clinical diagnosis for identifying the immediate cause of death in hospitalized patients: a prospective autopsy-based study

Despite 75 to 90 % physician accuracy in determining the underlying cause of death, precision of determination of the immediate cause of death is approximately 40 %. In contrast, two thirds of immediate causes of death in hospitalized patients are correctly diagnosed by postmortem computed tomography (CT). Postmortem CT might provide an alternative approach to verifying the immediate cause of death. To evaluate the effectiveness of postmortem CT as an alternative method to determine the immediate cause of death in hospitalized patients, an autopsy-based prospective study was performed. Of 563 deaths from September 2011 to August 2013, 50 consecutive cadavers undergoing hospital autopsies with consent for additional postmortem CT at the University of Fukui were enrolled. The accuracy of determination of the immediate cause of death by postmortem CT was evaluated in these patients. Diagnostic discrepancy was also compared between radiologists and attending physicians. The immediate cause of death was correctly diagnosed in 37 of 50 subjects using postmortem CT (74 %), concerning 29 cases of respiratory failure, 4 of hemorrhage, 3 of liver failure and 1 of septic shock. Six cases of organ failure involving 13 patients were not identified as the cause of death by postmortem CT. Regarding the immediate cause of death, accuracy of clinical diagnosis was significantly lower than that of postmortem CT (46 vs 74 %, P < 0.01). Postmortem CT may be more useful than clinical diagnosis for identifying the immediate cause of death in hospitalized patients not undergoing autopsy.

Reactive hemophagocytic syndrome in adults: a retrospective analysis of 162 patients

OBJECTIVES

Current knowledge in reactive hemophagocytic syndrome mainly relies on single-center case series including a relatively small number of patients. We aimed to identify a multicenter large cohort of adult patients with reactive hemophagocytic syndrome and to describe relevant clinical and laboratory features, underlying conditions, and outcome.

METHODS

We conducted a multicenter study in 3 tertiary care centers in France over a 6-year period. The medical files of 312 patients with suspected hemophagocytic syndrome were retrospectively reviewed. Patients were classified with a positive, negative, or undetermined diagnosis of hemophagocytic syndrome by experts' consensus.

RESULTS

Among the 312 patients fulfilling our inclusion criteria, 162 were classified with positive hemophagocytic syndrome (male, 67%; median age, 48 [35-62] years). Compared with patients without hemophagocytic syndrome, patients with hemophagocytic syndrome more frequently had an underlying immunodepression (45% vs 33%, P = .03) and exhibited higher temperature, ferritin, triglycerides, aspartate transaminase, bilirubin, lactate dehydrogenase, and C-reactive protein, and lower hemoglobin, leukocytes, platelets, and sodium levels. Only 70% of them had hemophagocytosis features on bone marrow aspiration. Hematologic malignancies, especially non-Hodgkin lymphomas, were the main trigger of hemophagocytic syndrome, accounting for 56% of cases. The early mortality rate (ie, within 1 month after diagnosis) was 20%. Patients with hematologic malignancies-associated hemophagocytic syndrome had a poorer early outcome than those with underlying infection.

CONCLUSIONS

In this large, multicenter study, hematologic malignancies are the main disease associated with hemophagocytic syndrome in adults. Early mortality is high, and outcome is influenced by the underlying disease.

Development and validation of the HScore, a score for the diagnosis of reactive hemophagocytic syndrome

OBJECTIVE

Because it has no unique clinical, biologic, or histologic features, reactive hemophagocytic syndrome may be difficult to distinguish from other diseases such as severe sepsis or hematologic malignancies. This study was undertaken to develop and validate a diagnostic score for reactive hemophagocytic syndrome.

METHODS

A multicenter retrospective cohort of 312 patients who were judged by experts to have reactive hemophagocytic syndrome (n = 162), were judged by experts to not have reactive hemophagocytic syndrome (n = 104), or in whom the diagnosis of reactive hemophagocytic syndrome was undetermined (n = 46) was used to construct and validate the reactive hemophagocytic syndrome diagnostic score, called the HScore. Ten explanatory variables were evaluated for their association with the diagnosis of hemophagocytic syndrome, and logistic regression was used to calculate the weight of each criterion included in the score. Performance of the score was assessed using developmental and validation data sets.

RESULTS

Nine variables (3 clinical [i.e., known underlying immunosuppression, high temperature, organomegaly], 5 biologic [i.e., triglyceride, ferritin, serum glutamic oxaloacetic transaminase, and fibrinogen levels, cytopenia], and 1 cytologic [i.e., hemophagocytosis features on bone marrow aspirate]) were retained in the HScore. The possible number of points assigned to each variable ranged from 0-18 for known underlying immunosuppression to 0-64 for triglyceride level. The median HScore was 230 (interquartile range [IQR] 203-257) for patients with a positive diagnosis of reactive hemophagocytic syndrome and 125 (IQR 91-150) for patients with a negative diagnosis. The probability of having hemophagocytic syndrome ranged from <1% with an HScore of ≤90 to >99% with an HScore of ≥250.

CONCLUSION

The HScore can be used to estimate an individual's risk of having reactive hemophagocytic syndrome. This scoring system is freely available online (http://saintantoine.aphp.fr/score/).

Risk factor analysis for bone marrow histiocytic hyperplasia with hemophagocytosis: an autopsy study

The excessive release of inflammatory cytokines occasionally induces life-threatening hemophagocytosis referred to as hemophagocytic syndrome (HPS). A similar condition, histiocytic hyperplasia with hemophagocytosis (HHH), is often seen in bone marrow collected during autopsy. Unlike HPS, the pathogenesis of HHH remains unclear. Therefore, we performed a clinicopathological analysis of HHH from 70 autopsy cases at the University of Fukui Hospital. HHH was detected in 29 of 70 autopsies (41.4 %) and was significantly complicated with hematological diseases (p < 0.05) and sepsis (p < 0.05). The percentage of macrophages in bone marrow (BM) nucleated cells was significantly increased in HHH (p < 0.001). Data from medical records indicated no significant changes, except for the minimum values of white blood cell counts (p < 0.05) and platelet counts (p < 0.05) in HHH patients as compared with non-HHH patients. Concentrations of inflammatory mediators including IL-1β, IL-6, and IL-8 were significantly increased in HHH patients. Multivariate risk factor analysis identified hematological diseases (odds ratio (OR), 11.71), ≥15 % BM macrophages (OR, 9.42), sepsis (OR, 7.77), and high serum IL-6 levels (OR, 1.00) as independent risk factors for HHH. HHH with hypocellular BM, the most aggressive form of HHH, was recognized in 8 of 29 HHH patients and was associated with ≥25 % BM macrophages (p < 0.001), leukocytopenia (p < 0.05), and high IL-8 levels (p < 0.05). None of the HHH patients fulfilled the diagnostic criteria of HPS. These findings suggest that HHH is a different entity from HPS and that it preferentially develops under conditions of excessive inflammation and its associated risks, such as hematological diseases and sepsis.

Marrow assessment for hemophagocytic lymphohistiocytosis demonstrates poor correlation with disease probability

OBJECTIVES

To evaluate the amount of hemophagocytosis in 64 marrow core biopsy specimens and aspirates from 58 patients with clinical suspicion for secondary hemophagocytic lymphohistiocytosis (HLH) or reported findings of hemophagocytosis.

METHODS

A review of medical records assigned patients to a low-risk (45 patients) or high-risk (13 patients) HLH group, and association with histologic findings was examined using the Fisher exact test.

RESULTS

The amount of hemophagocytosis in aspirate or the core biopsy specimen did not correlate with disease probability (P = .17 and P = .63, respectively). Of the clinical/laboratory criteria assessed, the most significant correlations with HLH were highly elevated ferritin (P = .01), cytopenias (P = .02), and fever (P = .009).

CONCLUSIONS

Our findings indicated that marrow histologic findings alone do not reliably predict the probability of HLH, and an isolated finding of hemophagocytosis, even when present in a high amount, lacks specificity for HLH.

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.

A case of rhesus hemolytic disease with hemophagocytosis and severe iron overload due to multiple transfusions

BACKGROUND

A newborn with cholestatic hepatic disease and hemophagocytic lymphohistiocytosis due to rhesus hemolytic disease (RHD) is reported.

OBSERVATION

A 34 weeks' gestation baby with RHD, who had received multiple intrauterine transfusions (IUT), developed cholestatic hepatic disease and secondary hemophagocytic lymphohistiocytosis (HLH). Her serum ferritin level increased to 5,527 ng/mL, and liver biopsy showed severe iron overload. Treatment with intravenous desferrioxamine resulted in a marked decrease in serum ferritin levels and normalization of liver function

CONCLUSION

We suggest that patients who have undergone IUT be evaluated for hyperferritinemia. If hyperferritinemia is noted, chelation therapy should be considered. As another rare finding, HLH can complicate the course of RHD.

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.

Liver involvement in the histiocytic disorders of childhood

The liver can be involved directly, by infiltration, and indirectly--by remote effects--in the histiocytoses of childhood. Langerhans cell disease, the most well recognized of these, infiltrates the liver directly but has a remarkable selectivity for the bile ducts. Early involvement is by Langerhans cell histiocytosis (LCH) infiltration leading to a sclerosing cholangitis and, eventually, biliary cirrhosis. Gamma glutamyl transpeptidase is a sensitive indicator of liver infiltration in a child with LCH. The indirect effects on the liver of LCH elsewhere in the body are mediated through an accompanying macrophage activation syndrome that is most likely responsible for hepatomegaly and hypoalbuminemia but without direct infiltration. These indirect effects are completely reversible. Juvenile xanthogranuloma/xanthoma disseminatum, a related dendritic cell disorder that can have systemic manifestations, has a strikingly different pattern, with a predominantly portal infiltrate spilling over into the adjacent lobule but sparing the biliary tree. The biology of the liver lesions is not clear but regression has been documented. Myeloproliferative disorders and myeloid leukemias can express CD1a and/or S100 protein, mimicking LCH but distinguished by their sinusoidal pattern. The primary macrophage histiocytoses such as the familial hemophagocytic syndromes can lead to severe liver damage. Although a portal lymphohistiocytic infiltrate is most characteristic, it is probably cytokine-mediated hepatocellular damage that can cause substantial functional impairment or even hepatic failure as a presenting feature. Liver involvement in other, more unusual histiocytic disorders, is also illustrated.

Cytology of the spleen

Fine-needle aspiration of the spleen is a useful method for evaluation of reactive, inflammatory, and neoplastic disorders, particularly those that involve the hematopoietic system. Interpretation of splenic aspirates is enhanced by concurrent evaluation of blood and other hemic tissues.

Thermophilic multidrug-resistant Campylobacter fetus infection with hypersplenism and histiocytic phagocytosis in a patient with acquired immunodeficiency syndrome

We present a case report of a patient who had acquired immunodeficiency syndrome (AIDS) and Campylobacter fetus infection with a number of unusual clinical and microbiological features. The patient had prominent gastrointestinal symptoms, splenic infarction, splenomegaly with hypersplenism, and hemophagocytic histiocytosis in the spleen and lymph nodes; the organism displayed growth on Campy-selective blood agar, thermotolerance, and resistance to quinolones, piperacillin/tazobactam, ceftazidime, and erythromycin.

Hemophagocytic syndrome presenting as acute hepatic failure in two infants: clinical overlap with neonatal hemochromatosis

Two patients with hemophagocytic lymphohistiocytosis who presented with acute liver failure are reported. Both presented with fever, hepatosplenomegaly, markedly elevated liver function tests, abnormal coagulation profiles, and an increase in serum ferritin. Both infants were diagnosed with neonatal hemochromatosis based on a clinical picture of hepatic insufficiency with hyperferritinemia and were referred for liver transplantation. The first patient died of liver failure and septicemia before transplantation. Review of autopsy material revealed a hepatitis-like pattern and extensive infiltration of liver and other organs including bone marrow by histiocytes, some of which were hemophagocytic. The second patient underwent liver transplantation but died 44 days thereafter from progressive hemophagocytic lymphohistiocytosis. Examination of the resected liver demonstrated a hepatitis-like pattern, proliferation of histiocytes, and hemophagocytosis, and the bone marrow revealed hemophagocytic histiocytosis. Hemophagocytosis recurred in the allograft. Hepatic manifestations are common in hemophagocytic lymphohistiocytosis and overt hepatic failure may occur, but initial presentation as fulminant hepatic failure is not well recognized. Elevated serum ferritin can make the distinction from neonatal hemochromatosis and other forms of neonatal liver failure difficult. Hemophagocytic lymphohistiocytosis should be considered in the differential diagnosis of neonatal liver disease, especially when it is accompanied by cytopenias.

Thrombocytopenia in a surgical ICU

STUDY OBJECTIVES

To assess the incidence of thrombocytopenia in surgical ICU patients, the factors associated with thrombocytopenia, the outcome of thrombocytopenic patients, and the possible mechanisms involved.

DESIGN

Prospective study.

SETTING

An 8-bed surgical ICU in an 885-bed teaching hospital.

PATIENTS

147 consecutive patients admitted to the surgical ICU during a 6-month period.

MAIN OUTCOME MEASURES

Incidence of thrombocytopenia (defined by a platelet count < 100,000/mm3), risk factors for thrombocytopenia, or death in thrombocytopenic patients identified by a stepwise logistic regression analysis, as well as the mechanisms involved.

RESULTS

Thrombocytopenia occurred in 52 patients (35%) with a mortality rate of 38%, compared with a 20% mortality rate in nonthrombocytopenic patients (p = 0.02). Sepsis, episodes of bleeding or transfusions, and an acute physiology and chronic health evaluation (APACHE) II score of > 15 were the independent risk factors identified for thrombocytopenia. The correction of thrombocytopenia was a protective factor reducing the risk of mortality in thrombocytopenic patients. Disseminated intravascular coagulation was found in 40% of thrombocytopenic patients, elevated platelet-associated IgG in 33%, and hemophagocytic histiocytes in 67%. Combinations of two of these mechanisms were demonstrated in one quarter of thrombocytopenic patients.

CONCLUSIONS

Sepsis was the major independent risk factor identified. Thrombocytopenic patients had a higher ICU mortality due to the severity of overall clinical status. Bone marrow examination could be diagnostic when no obvious causes are demonstrated. Thrombocytopenia probably reflects the severity and course of an underlying pathologic condition, as its correction appears to be a good prognostic factor.

Bone marrow cytological findings in 4 dogs and a cat with hemophagocytic syndrome

Hemophagocytic syndrome or hemophagic histiocytosis was diagnosed in 4 dogs and 1 cat by evaluation of bone marrow aspirate smears. One of the dogs had a suspected infection with canine parvovirus and a confirmed infection with Salmonella spp, 2 dogs had presumptive diagnoses of myeloproliferative and lymphoproliferative disease, respectively, and 1 dog died without a diagnosis. The cat had hepatic lipidosis and lesions compatible with feline calicivirus infection. All animals had cytopenias involving 2 or more cell lines, and fragmented erythrocytes in the blood, along with mild to moderate increases in the number of macrophages in the bone marrow. Numerous marrow macrophages contained phagocytized hematopoietic cells. Other cytological features of the bone marrow were variable in each patient, but the degree of response in the blood was inadequate, even in those with bone marrow hyperplasia. The phagocytosis of hematopoietic elements did not appear to be caused by a primary immune disorder, but rather by the inappropriate activation of normal macrophages secondary to infectious, neoplastic, or metabolic diseases. These findings suggest that hemophagocytic syndrome may be an important factor in the development of cytopenias; the data also support the cytological evaluation of bone marrow aspirates as an aid in the diagnosis of hemophagocytic syndrome.

Fatal vascular leak syndrome with extensive hemorrhage, peripheral neuropathy and reactive erythrophagocytosis: an unusual complication of recombinant IL-3 therapy

A 39-year-old patient with severe aplastic anemia (AA), resistant to therapy, received recombinant human IL-3 (rhIL-3) on a phase I/II trial. During treatment she developed disseminated skin lesions, suggestive of vasculitis, and severe progressive peripheral neuropathy culminating in complete paralysis. She died 25 days after beginning treatment from profuse bleeding. On autopsy, evidence of vascular leaks with widespread bleeding and extensive hemorrhagic involvement of peripheral nerves was found. An additional feature was massive reactive erythrophagocytosis in lymph nodes, spleen and bone marrow. The coincidence between rhIL-3 administration and the dramatic events suggest a causal relation. As a possible pathogenic mechanism, an rhIL-3 induced excessive stimulation of macrophages and production of secondary cytokines such as tumor necrosis factor (TNF) is suggested. TNF is considered as a major factor in the development of both a vascular leak and reactive erythrophagocytosis. This case report can be regarded as an example of the possible unusual pathologic phenomena we may expect to see in the near future with increasing use of growth factors.

Fetal lymphocyte subpopulations in red blood cell iso-immunised pregnancies

OBJECTIVE

To study the association between fetal anaemia and alterations in lymphocyte subpopulations.

DESIGN

Cross-sectional study.

SETTING

The Harris Birthright Research Centre for Fetal Medicine, King's College Hospital Medical School, London.

SUBJECTS

Forty-three red blood cell iso-immunised pregnancies undergoing cordocentesis at 19 to 38 weeks gestation.

MAIN OUTCOME MEASURES

Fetal blood haemoglobin concentration, erythroblast count and lymphocyte subpopulations.

RESULTS

The mean T (CD3+), B (CD19+), T-helper (CD4+), T-suppressor/cytotoxic (CD8+) and natural killer (NK: CD16+/CD56+) cell counts in the anaemic fetuses were significantly lower than the appropriate normal mean for gestation (CD3+: t = -3.25, P < 0.01; CD19+: t = -2.14, P < 0.05; CD4+: t -4.03, P < 0.001; CD8+: t = -3.39, P < 0.01 and CD16+/CD56+: t = -3.49, P < 0.01). Furthermore, there was a significant association between the decrease in T lymphocyte number and the degree of fetal anaemia (r = 0.342, P < 0.05).

CONCLUSIONS

Fetuses from red blood cell iso-immunised pregnancies exhibit nonselective lymphopenia that is proportional to the degree of anaemia.

Liver changes in reactive haemophagocytic syndrome

Hepatomegaly and deranged liver functions are common findings in reactive haemophagocytic syndrome (RHS). We report the findings of 12 fatal cases of RHS in which histological materials of the liver are available for study. The underlying diseases of these patients included lymphoma/leukaemia (6 cases), disseminated undifferentiated carcinoma of the ovary (1 case), disseminated nasopharyngeal carcinoma complicated by tuberculosis (1 case), adenovirus pneumonia (1 case), pneumococcal pneumonia (1 case), typhoid fever (1 case), and possible drug intoxication (1 case). Ten patients had involvement of the liver by the underlying disease process which contributed to the marked hepatic derangement. Non-specific reactive hepatitis, sinusoidal dilatation and steatosis resulting from systemic or local effects of the associated diseases and the haemophagocytosis also added to the high incidence of liver abnormalities. A diffuse Kupffer cell hyperplasia with haemophagocytosis is characteristic of the syndrome, as all the cases showed increased numbers of bland-looking histiocytes within the hepatic sinusoids and haemophagocytosis which was moderate to marked in 8 cases and mild in 4. Thus the finding of Kupffer cell hyperplasia with prominent haemophagocytosis in liver biopsy is indicative of an element of RHS and warrants clinical monitoring. Differential diagnoses of haemophagocytosis in liver are also discussed.

Proliferation of abnormal bone marrow histiocytes, an undesired effect of granulocyte macrophage-colony-stimulating factor therapy in a patient with Hurler's syndrome undergoing bone marrow transplantation

Granulocyte macrophage-colony-stimulating factor (GM-CSF) has shown promise as a means of alleviating leukopenia associated with a wide variety of disorders. It is currently undergoing evaluation as an adjunct to bone marrow transplantation but its use in patients with metabolic disorders, such as Hurler's syndrome (HS), has not been explored. We followed bone marrow morphology in a 2-year-old male with HS who received up to 8 micrograms/kg GM-CSF per day because of failure of allogeneic bone marrow engraftment. Both premortem and postmortem bone marrow sampling revealed almost complete replacement of the marrow space by sheets of histiocytes demonstrating metachromatic cytoplasmic granules. Such cells were present in far greater numbers than are usually seen in untreated patients with HS or patients with HS undergoing successful bone marrow transplantation without GM-CSF. Moreover, the in vitro culture of bone marrow from a second HS patient showed a GM-CSF dose-related increase in colony formation up to a dose of 250 units/ml. Microscopic examination of these colonies showed a high percentage of histiocytes identical to those seen in the patient's bone marrow. These observations suggest that caution should be exercised when considering administration of CSFs to patients with HS and similar metabolic storage diseases.

Reactive hemophagocytic syndrome--a clinicopathologic study of 40 patients in an Oriental population

PURPOSE

The purpose of this investigation was to assess the clinical spectrum and outcome of reactive hemophagocytic syndrome (RHS) in an Oriental population.

PATIENTS AND METHODS

The investigation was a retrospective study of 40 consecutive patients with RHS diagnosed over a 4-year period in Queen Elizabeth Hospital, a community-based hospital in Hong Kong.

RESULTS

The incidence of RHS in Hong Kong appeared to be comparable with that of Western countries. However, the spectrum of diseases associated with RHS was distinctly different. Forty percent of the cases were associated with malignant lymphoma. Another 40% of the cases were associated with infection, often due to bacteria, and infection due to the herpes group of viruses was uncommon, probably reflecting ethnic and geographic differences from the white population. Two patients had the acute lupus hemophagocytic syndrome, a distinctive form of RHS that occurs in patients with systemic lupus erythematosus. Treatment was basically supportive, with specific therapy also given for the underlying disease if present. Eighteen patients (45%) died of the acute disease, mostly as a result of complications of RHS or the underlying diseases. The development of disseminated intravascular coagulopathy was a poor prognostic factor.

CONCLUSIONS

RHS is an uncommon disorder in Hong Kong and is often associated with malignant lymphoma or bacterial infection. A rigorous search for an underlying malignancy or infection is thus warranted once this diagnosis is made.

Fetal leucocyte count in rhesus disease

The effect of fetal anaemia on the total and differential leucocyte counts was studied by examining blood samples obtained by cordocentesis from 177 previously untransfused rhesus affected fetuses at 17-36 weeks' gestation. The mean fetal total leucocyte, lymphocyte, and monocyte counts were significantly lower than the corresponding values in normal controls and there were significant associations between the decrease in these cells and the degree of fetal anaemia. Possible mechanisms for leucopenia include (i) stimulation of erythroid progenitor production at the expense of production of myeloid progenitors, (ii) non-specific haemophagocytosis, or (iii) general suppression of haemopoiesis. Further understanding of the underlying mechanism and the implications of leucopenia as well as the previously reported thrombocytopenia and anaemia may provide a basis for improved antenatal and/or postnatal treatment.

Sensorimotor neuropathy in hemophagocytosis syndrome

Hemophagocytosis syndromes are uncommon disorders marked by generalized proliferation of benign histiocytes and multiple organ failure. A 24-year-old woman presented with a fulminant illness consisting of fever, hepatic insufficiency and anemia, followed by respiratory compromise, cardiomyopathy, and uremia. She developed a sensorimotor polyneuropathy, with normal cerebrospinal fluid findings. Sural nerve biopsy demonstrated mild to moderate axonopathy, with regeneration and occasional segmental demyelination/remyelination. The recent and old hemorrhages present in the perineurium, and the marked infiltration by foamy histiocytes (macrophages) distributed mostly in the subperineural space, were presumably responsible for the Wallerian degeneration. Documentation of histiocytes in peripheral nerves in hemophagocytosis syndrome has not previously been shown.

The histiocytoses of childhood

The histiocytoses of childhood include Langerhans' cell histiocytosis, haemophagocytic syndrome (familial and reactive), sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease), juvenile xanthogranuloma and malignant histiocytosis. These disorders show wide variation in their clinical presentation, prognosis and genetic implications. All are characterized by localized or generalized proliferation of histiocytes, but they differ in their morphology, histochemical and immunochemical staining patterns and electronmicroscopical features. On the basis of a comprehensive clinical history and critical interpretation of morphology and immunocytochemistry using an appropriately selected panel of antibodies, a diagnosis can be reached in the majority of cases.