Targeted next-generation sequencing: a novel diagnostic tool for primary immunodeficiencies

BACKGROUND

Primary immunodeficiency (PID) disorders are a heterogeneous group of inherited disorders caused by a variety of monogenetic immune defects. Thus far, mutations in more than 170 different genes causing PIDs have been described. A clear genotype-phenotype correlation is often not available, which makes a genetic diagnosis in patients with PIDs complex and laborious.

OBJECTIVE

We sought to develop a robust, time-effective, and cost-effective diagnostic method to facilitate a genetic diagnosis in any of 170 known PID-related genes by using next-generation sequencing (NGS).

METHODS

We used both targeted array-based and in-solution enrichment combined with a SOLiD sequencing platform and a bioinformatic pipeline developed in house to analyze genetic changes in the DNA of 41 patients with PIDs with known mutations and 26 patients with undiagnosed PIDs.

RESULTS

This novel NGS-based method accurately detected point mutations (sensitivity and specificity >99% in covered regions) and exonic deletions (100% sensitivity and specificity). For the 170 genes of interest, the DNA coverage was greater than 20× in 90% to 95%. Nine PID-related genes proved not eligible for evaluation by using this NGS-based method because of inadequate coverage. The NGS method allowed us to make a genetic diagnosis in 4 of 26 patients who lacked a genetic diagnosis despite routine functional and genetic testing. Three of these patients proved to have an atypical presentation of previously described PIDs.

CONCLUSION

This novel NGS tool facilitates accurate simultaneous detection of mutations in 161 of 170 known PID-related genes. In addition, these analyses will generate more insight into genotype-phenotype correlations for the different PID disorders.

Spectrum of imaging appearances in Australian children with central nervous system hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare multisystem disorder characterised by the proliferation and infiltration of lymphocytes and histiocytes. Central nervous system (CNS) infiltration is particularly devastating. Neuroradiological findings have been reported predominantly as individual case reports due to the rarity of the condition. To our knowledge there have been no published studies of imaging in Australian patients. This study aimed to retrospectively describe and illustrate the MRI appearances of CNS involvement by HLH in a cohort of seven Australian children from two paediatric centres between 2000 and 2011. MRI appearances demonstrate intersubject and intrasubject variability over time, likely reflecting the severity of CNS infiltration and associated demyelination. Familiarity with MRI patterns is important for assessing and monitoring disease activity.

An ironic case of liver infections: Yersinia enterocolitis in the setting of thalassemia

A 49 years old Vietnamese male with a history of thalassemia, presented with gastrointestinal symptoms and signs of hemolysis. He was diagnosed with yersinia enterocolitis. Yersinia is a gram-negative rod that most frequently occurs in children especially during the winter months. In the current case, the bone marrow biopsy showed hemophagocytosis along with positive cultures for Yersinia. The microorganism likely triggered hemophagocytosis. This syndrome, also known as, hemophagocytic lymphohistiocytosis, is defined by fever for more than 7 d, cytopenia of two or more cell lines, hemophagocytosis, hepatitis, serum ferritin greater than 500, jaundice, lymphadenopathy, and hepatosplenomegaly. This disorder can be either familial or secondary to a strong immunologic activation. Both have an overwhelming activation of T-cells and macrophages.

Macrophage activation syndrome secondary to human monocytic ehrlichiosis

OBJECTIVES

To present a case of human monocytic ehrlichiosis (HME) that was complicated by macrophage activation syndrome (MAS), also known as secondary hemophagocytic lymphohistiocytosis (sHLH).

METHODS

Data was collected from patient's electronic medical records at the University of Alabama at Birmingham. The patient is a part of a larger cohort of patients with all-cause MAS treated at our center.

CASE

A 63 year old renal transplant recipient male on maintenance immunosuppressive therapy presented with high grade fever, leukopenia, thrombocytopenia and elevated transaminases and initially met clinical criteria for severe sepsis. On further investigation, clinical and laboratory criteria for MAS were met. He was treated with a combination of doxycycline for HME and a novel combination of anakinra (interleukin-1 receptor antagonist), and high dose corticosteroids. The discussion focuses on clinical presentation, pathogenesis and treatment of MAS with an emphasis on MAS secondary to HME.

CONCLUSION

Macrophage activation syndrome or sHLH is a dysfunctional, hyperactive and potentially fatal immune system response that results in multi-organ dysfunction. With increasing incidence of Ehrlichia chaffeensis as an emerging pathogen, clinicians should be aware of this fulminant and potentially fatal complication of HME.

An intermediate alemtuzumab schedule reduces the incidence of mixed chimerism following reduced-intensity conditioning hematopoietic cell transplantation for hemophagocytic lymphohistiocytosis

Reduced-intensity conditioning (RIC) improves the outcomes of hematopoietic cell transplantation (HCT) in patients with hemophagocytic lymphohistiocytosis (HLH). Proximal (ie, close to graft infusion) dosing of alemtuzumab is associated with a high incidence of mixed chimerism, whereas distal (ie, distant from graft infusion) dosing is associated with less mixed chimerism but more acute graft-versus-host disease (GVHD). The alemtuzumab dose per kilogram of body weight also influences these outcomes. We hypothesized that an intermediate alemtuzumab dosing schedule would reduce mixed chimerism and maintain a low incidence of acute GVHD. In this study, 24 consecutive HCTs were performed in patients with HLH or a related disorder using a novel intermediate alemtuzumab schedule of 1 mg/kg starting on day -14. The cumulative incidences (CIs) of mixed chimerism, upfront acute GVHD grades II-IV, and receipt of additional hematopoietic cell products after HCT were compared in patients treated with a distal alemtuzumab schedule (n = 15) and those treated with a proximal alemtuzumab schedule (n = 33). All patients received fludarabine and melphalan. The CI of mixed chimerism was 31% in the intermediate group, 72% in the proximal group (P < .01), and 75% in the distal group patients who received ≥2 mg/kg alemtuzumab (P = .03). The CI of acute GVHD grades II-IV before the development of mixed chimerism was 4% in the intermediate group, 0% in the proximal group, and 13% in the distal group (P = .04, proximal versus distal). The 1-year CI of administration of additional hematopoietic cell products for mixed chimerism (donor lymphocyte infusion ± hematopoietic stem cell boost ± repeat HCT) was 14% in the intermediate group, 53% in the proximal group (P = .01), and 38% in the distal ≥2 mg/kg alemtuzumab group (P = .02). Our findings indicate that intermediate RIC reduces the incidence of mixed chimerism, is associated with a low incidence of upfront acute GVHD, and decreases the need for additional hematopoietic cell products after HCT.

Hemophagocytic lymphohistiocytosis masking the diagnosis of lymphoma in an adolescent male

Hemophagocytic lymphohistiocytosis (HLH) association with an underlying lymphoma is an uncommon entity in paediatrics. It may precede lymphoma diagnosis by several years or may occur at the time of remission or relapse of lymphoma. Simultaneous occurrence of HLH & lymphoma is rare. We here with report a case where HLH was the initial presentation which masked the diagnosis of lymphoma, however tissue biopsy revealed the underlying non-Hodgkin's lymphoma.

X-linked inhibitor of apoptosis (XIAP) deficiency: the spectrum of presenting manifestations beyond hemophagocytic lymphohistiocytosis

X-linked inhibitor of apoptosis (XIAP) deficiency caused by mutations in BIRC4 was initially described in patients with X-linked lymphoproliferative syndrome (XLP) who had no mutations in SH2D1A. In the initial reports, EBV-associated hemophagocytic lymphohistiocytosis (HLH) was the predominant clinical phenotype. Among 25 symptomatic patients diagnosed with XIAP deficiency, we identified 17 patients who initially presented with manifestations other than HLH. These included Crohn-like bowel disease (n=6), severe infectious mononucleosis (n=4), isolated splenomegaly (n=3), uveitis (n=1), periodic fever (n=1), fistulating skin abscesses (n=1) and severe Giardia enteritis (n=1). Subsequent manifestations included celiac-like disease, antibody deficiency, splenomegaly and partial HLH. Screening by flow cytometry identified 14 of 17 patients in our cohort. However, neither genotype nor protein expression nor results from cell death studies were clearly associated with the clinical phenotype. Only mutation analysis can reliably identify affected patients. XIAP deficiency must be considered in a wide range of clinical presentations.

Hemophagocytic lymphohistiocytosis mimicking surgical symptoms and complications: lessons learned from four cases

OBJECTIVE

Hemophagocytic lymphohistiocytosis (HLH) is a severe immunological disorder that leads to a massive inflammatory reaction that may prove rapidly fatal. We show that HLH may present by masquerading as surgical disease or as a postoperative complication leading to delays in diagnosis and treatment.

STUDY DESIGN

A case series of four children with acute surgical presentation and prolonged unexplained postoperative sepsis, who were diagnosed with HLH.

RESULTS

Four children with different clinical presentations (1. neonatal abdominal distension, 2. ileostomy closure and Hirschsprung's disease, 3. iatrogenic sigmoid perforation and Crohn's disease, and 4. streptococcal toxic shock syndrome with primary peritonitis) were diagnosed with HLH at our regional pediatric surgical centre in the last two years. All developed signs of prolonged postoperative sepsis with hepatosplenomegaly and pancytopenia, requiring intensive care support. In the absence of explanation for their symptoms and deteriorating clinical condition, a total of six 'negative' exploratory laparotomies were performed. Eventually, HLH was diagnosed with bone marrow aspiration after an average of 23 days (range 17-40), following the finding of significantly elevated ferritin (up to 293150 ng/ml) and triglyceride levels. All children improved with initiation of high-dose steroid treatment followed by etoposide and cyclosporin.

CONCLUSION

HLH may rarely present with symptoms and signs of surgical disease or complicate post-operative recovery. This diagnosis should be considered in children with unexplained prolonged fever, hepatosplenomegaly and pancytopenia, especially if associated with high ferritin levels. HLH can prove rapidly fatal without appropriate treatment.

Hemophagocytic lymphohistiocytosis: an update on diagnosis and pathogenesis

Hemophagocytic lymphohistiocytosis (HLH) is a frequently fatal and likely underdiagnosed disease involving a final common pathway of hypercytokinemia, which can result in end-organ damage and death. Although an early diagnosis is crucial to decrease mortality, the definitive diagnosis is often challenging because of the lack of specificity of currently accepted diagnostic criteria and the absence of confirmatory gold standards. Because of the wide range of laboratory assays involved in the diagnosis of HLH, practicing pathologists from a broad spectrum of clinical specialties need to be aware of the disease so that they may appropriately flag results and convey them to their clinical counterparts. Our article summarizes these new advances in the diagnosis of HLH and includes a review of clinical findings, updated understanding of the pathogenesis, and promising new testing methods.

Hemophagocytic syndrome in severe dengue Fever: a rare presentation

We describe a 2-year old boy developing virus-associated hemophagocytic syndrome in severe dengue fever. The condition was diagnosed according to the established criteria of the International Histiocyte Society. There was uneventful recovery with corticosteroid therapy. Secondary hemophagocytosis in children can mimic severe sepsis, systemic inflammatory response syndrome, or multi organ dysfunction syndrome and lead to diagnostic difficulties. This report adds to the limited pediatric cases of dengue related hemophagocytic syndrome reported in literature; and underlines the importance of prompt diagnosis and appropriate treatment of this rare but serious complication.

Severe hemophagocytic lymphohistiocytosis in adults-experience from an intensive care unit from North India

Background:

Hemophagocytic lymphohistiocytosis (HLH) has been reported to complicate fulminant tropical infections but data on severe HLH with multi-organ dysfunction (MODS) are scant.

Materials and Methods:

Retrospective review of medical electronic records of our intensive care unit (ICU) over a 2-year period.

Results:

We describe 10 adult patients with HLH and MODS. Patients had short symptom duration prior to presentation and had rapid deterioration during their hospitalization course. Fever, organomegaly, neurologic abnormalities, hepatic abnormalities, and cutaneous signs were very common. No patient had diagnosed HLH at ICU admission (median 4 criteria [Inter Quartile Range 2-4.25]). All patients required mechanical ventilation and 80% required vasopressors. Infection-associated HLH (IAHS) was the most common etiology (80%). Seventy percent (7/10) of patients were treated with steroids and 20% received intravenous immunoglobulin. Etoposide and/or cyclosporine were administered in 20% (2/10). Nosocomial infections occurred in 40% and the ICU mortality was 70%.

Conclusions:

Severe HLH with MODS has a very high mortality. Data on adult cohorts with IAHS in the tropics with defined treatment protocols are urgently needed.

Very high serum ferritin levels in three newborns with Kawasaki-like illness

Kawasaki disease (KD) is an inflammatory condition of unknown etiology that affects children, with a peak incidence in the second year of life. KD is uncommon in the first year of life and is rare in the newborn period. The present report describes three newborn infants who were admitted to hospital with fever and nearly identical clinical features of generalized inflammation. The presentations did not meet the criteria for KD; however, all three patients responded promptly and completely to intravenous immunoglobulin treatment. Specifically, the association of these presentations with very high levels of serum ferritin is reported. The authors propose that this clinical syndrome represents a variant of KD, and that serum ferritin level may be a useful marker in diagnosing KD and its variants. Additionally, the association of this clinical picture with very high serum ferritin levels raises the possibility of a link with hemophagocytic lymphohistiocytosis.

Epstein-barr virus-induced hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is one of the complications of Epstein-Barr virus (EBV) infection. Although the patients who have developed HLH following EBV have normal immune system, there are a few patients with EBV-induced immune deficiency who develop HLH as well. Here, we describe the case of a 10-year-old girl with neurological complications caused by EBV-induced HLH. The patient received rituximab, leading to weakening inflammation associated with EBV infection and suppression of disease through quick treatment.

Central nervous system (CNS) involvement is a critical prognostic factor for hemophagocytic lymphohistiocytosis

Background

Hemophagocytic lymphohistiocytosis (HLH) is a rare multisystem disorder that frequently involves the central nervous system (CNS). We compared the clinical characteristics, treatment, and prognosis of patients with HLH according to the degree of CNS involvement.

Methods

The clinical manifestations, initial laboratory data, treatment, and outcomes for 50 patients diagnosed with HLH and treated at Asan Medical Center between January 1995 and August 2011 were retrospectively reviewed and analyzed. CNS involvement was defined as the presence of neurological symptoms or an elevated white blood cell (WBC) count in the cerebrospinal fluid (CSF).

Results

Among these 50 patients, 23 (46%) developed CNS disease. Among patients with CNS disease, 19 had neurological symptoms, including seizures, altered consciousness, facial palsy, dysarthria, and dysphagia. Four patients had elevated CSF WBC counts without neurological symptoms. Twelve patients had abnormal brain imaging results, including high signal intensity lesions on T2-weighted magnetic resonance imaging (MRI) findings, ventriculomegaly, hemorrhage, atrophy, and leptomeningeal enhancement. Patients with CNS disease had lower ferritin, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels as well as reduced 5-year survival as compared to those without CNS disease.

Conclusion

CNS involvement is common among patients with HLH. Overall, patients with CNS disease achieve poorer outcomes than patients without CNS involvement. To improve outcomes, physicians must carefully monitor the neurological manifestations in patients with HLH and administer the appropriate course of intensified chemotherapy to patients with CNS disease.

An unusual presentation of galactosemia: hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening condition. Uncontrolled proliferation of activated lymphocytes secreting high amounts of inflammatory cytokines seems to be the main pathogenesis. The diagnosis of HLH can often be difficult. It may presents in many forms such as fever of unknown origin, hepatitis, acute liver failure, and sepsis-like illness. Here we present a newborn galactosemia case presented with HLH. Close monitoring of the diagnostic criteria of HLH during the course of galactosemia-associated hemophagocytosis, both before and after dietary treatment, should be performed in order to fully determine if the triggering mechanism is infection or accumulation of metabolites.

Conflict of interest:None declared.

Epstein-barr virus infection masquerading as acute leukemia: a report of two cases and review of literature

Epstein-Barr virus (EBV) is the first herpes virus to be completely sequenced. It is implicated in diseases from the benign infectious mononucleosis to malignant nasopharyngeal carcinoma, Burkitt's lymphoma and primary CNS lymphoma in AIDS patients. It has also been found to be associated with some miscellaneous diseases like chronic fatigue syndrome, multiple sclerosis etc. however causality still remains an issue of debate. As the virus mainly targets the lymphomonuclear cells and the reticuloendothelial system of the body, it's various manifestations are often mistaken as leukemic malignancies. We report two such cases of young adults who had been diagnosed as having acute leukemia on the basis of atypical cells in the peripheral blood. One patient later turned out to be a classical infectious mononucleosis and second patient had EBV associated hemophagocytic lymphohistiocytosis syndrome.

Drug associated vanishing bile duct syndrome combined with hemophagocytic lymphohistiocytosis

A 28-year-old woman with untreated autoimmune disorder, demonstrated skin rash and fever after taking Amoxicillin-clavulanate and developed progressive jaundice. A bone marrow aspiration indicated an increased number of macrophages with hemophagocytosis and liver biopsy showed pure centrilobular cholestasis with necrosis and some absence of portal bile ducts. Furthermore, a serological test for Epstein-Barr virus was positive. Under treatment by liver dialysis and administration of steroids led to rapidly defervescence and clinical improvement. However, liver enzymes were still markedly elevated with persistent anemia, even after immunosuppressive treatment. The patient is currently waiting for liver transplantation. This is the first description of vanishing bile duct syndrome combined with hemophagocytic lymphohistiocytosis, with underlying causes including infection, drug-induced factors and untreated autoimmune disorder.

Hemophagocytic lymphohistiocytosis of indeterminate cause: a fatal adult case

Hemophagocytic lymphohistiocytosis (HLH) is an uncommon life-threatening disorder characterized by wide spread non-neoplastic proliferation and inappropriate activation of mature macrophages resulting in hypercytokinemia. This uncontrollable and ineffective systemic immune response causes fever, hepatosplenomegaly, cytopenias and subsequently multiorgan failure. The authors report a case of a 41-year-old male patient with a 30-day history of weight loss, fever, icterus, hepatomegaly, and cytopenias. The diagnostic workup disclosed hypertriglyceridemia, hypofibrinogenemia, and elevated ferritin. Bone marrow examination and clinical course raised the suspicion of HLH and treatment was started with high-dose corticosteroids and immune globulin. The patient underwent multi-organ failure and expired after 58 days of hospitalization. The autopsy finding included massive bone marrow infiltration by non-neoplastic histiocytes, many of them showing hemophagocytosis, which immunohistochemical study revealed diffuse CD68-positive histiocytes, which were negative for S100 protein. Hemophagocytosis was also observed in the lungs, lymph nodes and liver. The immediate cause of death was attributed to a massive intestinal bleeding due to extensive ischemic necrosis at the duodenum/jejunal transition area.

Hemophagocytic Lymphohistiocytosis (HLH) Associated with Plasmodium vivax Infection: Case Report and Review of the Literature

Hemophagocytic lymphohistiocytosis (HLH) is an unusual syndrome characterized by fever, hepatosplenomegaly, cytopenias, hypertriglyceridemia, hypofibrinogenemia, and pathologic findings of hemophagocytosis in the bone marrow and other tissues. HLH may be familial or associated with different types of infections, autoimmune disorders, or malignancies. Infection-associated HLH has been reported in various viral, bacterial, fungal, and parasitic infections, and case reports of parasitic infections implicated in HLH include rare cases from Plasmodium vivax infection, which occasionally affects both military personnel and civilians in Korea. We describe an unusual case of HLH resulting from Plasmodium vivax infection and review the literature. This case suggests that clinical suspicion of HLH is important when P. vivax infection is accompanied by cytopenias. Administration of antimalarial drugs may prevent irreversible end organ damage resulting from P. vivax-associated HLH.

Hemophagocytic Lymphohistiocytosis in Association With Clostridium difficile Infection and Cutaneous T-Cell Lymphoma

Hemophagocytic lymphohistiocytosis (HLH) or Macrophage Activation Syndrome (MAS) is a potentially life threatening disorder that presents with fever, suppressed blood cell counts, hepatosplenomegaly and multi-organ failure. HLH has been reported in association with genetic mutations, infections, autoimmune disorders, and various malignancies. However to the best of our knowledge, HLH in association with Clostridium difficile infection has never been reported. We present a case of HLH in a patient with Epstein-Barr virus (EBV) positive natural killer T (NKT) cell cutaneous lymphoma and active Clostridium difficile infection. A 35-year-old male with recently diagnosed EBV positive NKT cell lymphoma was admitted for Clostridium difficile associated diarrhea. During the course of hospitalization he gradually developed pancytopenia and multi-organ failure leading to death. Post-mortem examination confirmed the diagnosis of hemophagocytic lymphohistiocytosis.