Tuberculous brain abscess in a patient with hyper IgE syndrome

Cytokines and their role as immunotherapeutics and vaccine Adjuvants: The emerging concepts

Cytokines are a protein family comprising interleukins, lymphokines, chemokines, monokines and interferons. They are significant constituents of the immune system, and they act in accordance with specific cytokine inhibiting compounds and receptors for the regulation of immune responses. Cytokine studies have resulted in the establishment of newer therapies which are being utilized for the treatment of several malignant diseases. The advancement of these therapies has occurred from two distinct strategies. The first strategy involves administrating the recombinant and purified cytokines, and the second strategy involves administrating the therapeutics which inhibits harmful effects of endogenous and overexpressed cytokines. Colony stimulating factors and interferons are two exemplary therapeutics of cytokines. An important effect of cytokine receptor antagonist is that they can serve as anti-inflammatory agents by altering the treatments of inflammation disorder, therefore inhibiting the effects of tumour necrosis factor. In this article, we have highlighted the research behind the establishment of cytokines as therapeutics and vaccine adjuvants, their role of immunotolerance, and their limitations.

FUNGAL NEUROLOGICAL SEQUELAE IN A HYPER IMMUNOGLOBULIN E SYNDROME FROM PESHAWAR, PAKISTAN: AN UNUSUAL PRESENTATION

Hyper IGE syndrome is one of the primary immunodeficiency syndromes characterized by the presence of abnormally raised serum IGE levels (2000 IU/ml) with defective humoral and cell mediated immunity presenting in infancy or early childhood. It is a rare disease with only about 200 cases reported in literature. Usually, it is diagnosed clinically and by raised serum IGE levels. Mostly, it presents with recurrent staphylococcal skin abscesses, sinopulmonary infections, and opportunistic mycotic infections due to the immunodeficient state. Rarely, the central nervous system is involved by this condition.This case study deals with an 11-year-old girl who was diagnosed as a case of hyper IGE syndrome. She presented with low GCS and focal neurological deficits which were attributed to aspergillus fumigatus infection spreading to the brain resulting in multiple abscesses and eventually to death of the patient despite treatment interventions. This case emphasizes the likelihood of dissemination of fungal infections to multiple organs including the brain and the potential role of early neuroimaging to detect such lesions. Moreover, it shows significance of serial imaging in admitted patients particularly with the onset of new and unusual neurological symptoms. With more extensive studies, we may be able to diagnose and treat such infections and their complications on time with better outcomes.

STAT3 Hyper-IgE Syndrome-an Update and Unanswered Questions

The hyper-IgE syndromes (HIES) are a heterogeneous group of inborn errors of immunity sharing manifestations including increased infection susceptibility, eczema, and raised serum IgE. Since the prototypical HIES description 55 years ago, areas of significant progress have included description of key disease-causing genes and differentiation into clinically distinct entities. The first two patients reported had what is now understood to be HIES from dominant-negative mutations in signal transduction and activator of transcription 3 (STAT3-HIES), conferring a broad immune defect across both innate and acquired arms, as well as defects in skeletal, connective tissue, and vascular function, causing a clinical phenotype including eczema, staphylococcal and fungal skin and pulmonary infection, scoliosis and minimal trauma fractures, and vascular tortuosity and aneurysm. Due to the constitutionally expressed nature of STAT3, initial reports at treatment with allogeneic stem cell transplantation were not positive and treatment has hinged on aggressive antimicrobial prophylaxis and treatment to prevent the development of end-organ disease such as pneumatocele. Research into the pathophysiology of STAT3-HIES has driven understanding of the interface of several signaling pathways, including the JAK-STAT pathways, interleukins 6 and 17, and the role of Th17 lymphocytes, and has been expanded by identification of phenocopies such as mutations in IL6ST and ZNF341. In this review we summarize the published literature on STAT3-HIES, present the diverse clinical manifestations of this syndrome with current management strategies, and update on the uncertain role of stem cell transplantation for this disease. We outline key unanswered questions for further study.

Human STAT3 variants underlie autosomal dominant hyper-IgE syndrome by negative dominance

Most patients with autosomal dominant hyper-IgE syndrome (AD-HIES) carry rare heterozygous STAT3 variants. Only six of the 135 in-frame variants reported have been experimentally shown to be dominant negative (DN), and it has been recently suggested that eight out-of-frame variants operate by haploinsufficiency. We experimentally tested these 143 variants, 7 novel out-of-frame variants found in HIES patients, and other STAT3 variants from the general population. Strikingly, all 15 out-of-frame variants were DN via their encoded (1) truncated proteins, (2) neoproteins generated from a translation reinitiation codon, and (3) isoforms from alternative transcripts or a combination thereof. Moreover, 128 of the 135 in-frame variants (95%) were also DN. The patients carrying the seven non-DN STAT3 in-frame variants have not been studied for other genetic etiologies. Finally, none of the variants from the general population tested, including an out-of-frame variant, were DN. Overall, our findings show that heterozygous STAT3 variants, whether in or out of frame, underlie AD-HIES through negative dominance rather than haploinsufficiency.

Hyperimmunoglobulin E syndrome: Genetics, immunopathogenesis, clinical findings, and treatment modalities

The hyperimmunoglobulin E syndromes (HIESs) are very rare immunodeficiency syndromes with multisystem involvement, including immune system, skeleton, connective tissue, and dentition. HIES are characterized by the classic triad of high serum levels of immunoglobulin E (IgE), recurrent staphylococcal cold skin abscess, and recurrent pneumonia with pneumatocele formation. Most cases of HIES are sporadic although can be inherited as autosomal dominant and autosomal recessive traits. A fundamental immunologic defect in HIES is not clearly elucidated but abnormal neutrophil chemotaxis due to decreased production or secretion of interferon γ has main role in the immunopathogenesis of syndrome, also distorted Th1/Th2 cytokine profile toward a Th2 bias contributes to the impaired cellular immunity and a specific pattern of infection susceptibility as well as atopic-allergic constitution of syndrome. The ophthalmic manifestations of this disorder include conjunctivitis, keratitis, spontaneous corneal perforation, recurrent giant chalazia, extensive xanthelasma, tumors of the eyelid, strabismus, and bilateral keratoconus. The diagnosis of HIES is inconclusive, dependent on the evolution of a constellation of complex multisystemic symptoms and signs which develop over the years. Until time, no treatment modality is curative for basic defect in HIES, in terms of cytokines/chemokines derangement. Of note, bone marrow transplant and a monoclonal anti-IgE (omalizumab) are hoped to be successful treatment in future.

Brain Abscess and Keratoacanthoma Suggestive of Hyper IgE Syndrome

Hyper immunoglobulin-E (IgE) syndrome is an autosomal immune deficiency disease. It is characterized by an increase in IgE and eosinophil count with both T-cell and B-cell malfunction. Here, we report an 8-year-old boy whose disease started with an unusual skin manifestation. When 6 months old he developed generalized red, nontender nodules and pathologic report of the skin lesion was unremarkable (inflammatory). Then he developed a painless, cold abscess. At the age of 4 years, he developed a seronegative polyarticular arthritis. Another skin biopsy was taken which was in favor of Keratoacanthoma. Laboratory workup for immune deficiency showed high eosinophil count and high level of immunoglobulin-E, due to some diagnostic criteria (NIH sores: 41 in 9-year-olds), he was suggestive of hyper IgE syndrome. At the age of 8, the patient developed an abscess in the left inguinal region. While in hospital, the patient developed generalized tonic colonic convulsion and fever. Brain computed tomography scan revealed an abscess in the right frontal lobe. Subsequently magnetic resonance imaging (MRI) of the brain indicated expansion of the existing abscess to contralateral frontal lobe (left side). After evacuating the abscesses and administrating intravenous antibiotic, the patient's condition improved dramatically and fever stopped.

Cytokine immunomodulation for the treatment of infectious diseases: lessons from primary immunodeficiencies

Traditionally, management of infectious diseases focuses on identification of the causative microbe and the use of pathogen-targeted therapy. With increasing antimicrobial resistance, novel approaches are required. One strategy is to modulate those natural host immune responses that critically mediate resistance to specific microbes. Clinically, this host-directed tactic could be used either alone or in combination with antimicrobial therapy. While conceptually attractive, there is potential concern that the pathways governing host resistance to pathogens in animal models may not extrapolate linearly to humans. Targeting these immune processes clinically may precipitate damaging, epiphenomenal responses. The field of Primary Immunodeficiencies focuses on the characterization of humans with inborn errors of immunity. These rare conditions permit the identification of those molecular and cellular processes that are central to human susceptibility to microbes. In efforts to compensate for defective host responses, this field has also provided a wealth of clinical experience in the effective use of cytokines to treat various active infections, while demonstrating their safety. In this review, we provide a historical perspective of the treatment of infectious diseases, evolving from a focus on the microbe, to an understanding of human immunity; we then outline the growing contribution of Primary Immunodeficiencies to the rational use of adjunctive cytokine immunotherapy in the management of infections.

Hyper IgE syndrome

Hyper IgE syndrome (HIES) is a rare disorder characterized by eczema, recurrent infections of the skin and lungs, typically with Staphylococcus aureus, Candida albicans and certain viruses, and elevated levels of serum IgE. Other clinical manifestations include characteristic facies (prominent forehead, broad nasal bridge and facial asymmetry), chronic eczematous dermatitis, retained primary dentition, recurrent pathological fractures, hyper-extensibility and scoliosis. The central nervous system (CNS) involvement in HIES has been rarely reported. Here we presented a case of HIES with rare associations of epilepsy in a young patient to raise awareness for this disorder.

Tuberculous brain abscesses in immunocompetent patients: management and outcome

BACKGROUND

Tuberculosis (TB) remains an important public health problem in developing countries.

OBJECTIVE

To evaluate the clinical presentation, management, and long-term outcome in 6 patients with tuberculous brain abscesses (TBA), an uncommon form of central nervous system (CNS) TB.

METHODS

A search of medical records of a single referral neurological center in Mexico City from 2002 to 2007 retrieved 149 patients with CNS TB; 6 of them (4%) met Whitener's criteria for TBA and were included in this review.

RESULTS

Five of six patients had a previous history of TB. Three patients were referred to our center under antituberculous treatment (ATT) for pulmonary and lymph node TB, and two patients were receiving ATT for TB meningitis at diagnosis of TBA. All presented with symptoms of intracranial hypertension and hemiparesis. On imaging studies, 3 patients had a single, deep multiloculated lesion and another three had separated lesions, all patients underwent surgery and received long courses of ATT. One patient died after surgery and the rest recovered with moderate to severe neurological sequelae. The residual lesions in 5 patients resolved in follow-up CT or MRI studies at a mean time of 10 months.

CONCLUSIONS

Early surgery confirms the diagnosis of TBA. Some patients may require additional surgical procedures if enlargement or recurrence of the lesion occurs. No evidence of drug resistance was found in our cases, and we found only two reports of TBA with primary resistance to ATT in a selective literature review. TBA does not seem to be a consequence of drug resistance. Sequelae are common, and long-term ATT with close clinical and imaging follow-up is mandatory.

Novel primary immunodeficiencies revealed by the investigation of paediatric infectious diseases

Human primary immunodeficiencies impairing myeloid and/or lymphoid cellular responses to activating receptors other than antigen receptors have recently been described in children with various infectious diseases. Germline mutations in NEMO and IKBA impair NF-kappaB-mediated signalling, at least in response to the stimulation of TLRs, IL-1Rs and TNFRs, and confer a broad predisposition to infections. Mutations in IRAK4 selectively impair TLRs other than TLR3 and most IL-1R responses, and confer a predisposition to pyogenic bacterial diseases, including invasive pneumococcal disease in particular. Mutations in TLR3 and UNC93B1 impair TLR3 responses and confer a predisposition to herpes simplex encephalitis. Mutations in STAT1 impair IFN-gamma and/or IFN-alpha/beta responses and predispose subjects to mycobacterial and viral diseases, respectively. Mutations in IFNGR1 and IFNGR2 impair IFN-gamma responses and confer a predisposition to mycobacterial diseases. Mutations in IL12B and IL12RB1 impair IL-12 and IL-23 responses and predispose subjects to infections caused by mycobacteria and Salmonella. Finally, mutations in TYK2 and STAT3 mostly impair IL-6R responses, conferring a predisposition to staphylococcal disease in particular. The infectious phenotypes associated with these novel leukocyte activation deficiencies are therefore collectively diverse, tightly dependent on the morbid gene and affected pathway, and individually narrow, often restricted to one or a few infectious diseases.

Hyperimmunoglobulin E syndrome and tyrosine kinase 2 deficiency

PURPOSE OF REVIEW

The purpose of the review is to provide recent insight into the pathogenesis and pathophysiology of hyperimmunoglobulin E syndrome.

RECENT FINDINGS

We recently identified a homozygous four base-pair deletion in the coding region of the tyrosine kinase 2 gene in a hyperimmunoglobulin E syndrome patient who exhibited susceptibility to intracellular bacteria.

SUMMARY

Hyperimmunoglobulin E syndrome is a primary immunodeficiency characterized by recurrent staphylococcal skin abscesses and pneumonia, and elevated serum immunoglobulin E. This syndrome is subdivided into types 1 and 2. Type 1 displays abnormalities in multiple systems, including the skeletal/dental and immune systems, whereas type 2 abnormalities are confined to the immune system. We recently identified a homozygous mutation in the tyrosine kinase 2 gene in a type 2 patient. Analyses of cytokine responses in the patient's cells revealed that the tyrosine kinase 2 deficiency had resulted in severe impairment of the signal transduction for multiple cytokines, including interleukin-6, -10, -12 and -23, and interferon-alpha/beta. The cytokine signals were successfully restored by transducing the intact tyrosine kinase 2 gene. Thus, tyrosine kinase 2 plays obligatory roles in human immunity. Based on this finding, we propose that hyperimmunoglobulin E syndrome is a primary immunodeficiency caused by genetic alterations leading to the defect in multiple cytokine signals.

Brain abnormalities in patients with hyperimmunoglobulin E syndrome

OBJECTIVES

Hyperimmunoglobulin E syndrome is a multisystem disorder with abnormalities of the immunologic, connective tissue, and skeletal tissue systems. Central nervous system abnormalities have not been considered a feature of hyperimmunoglobulin E syndrome. We aimed to determine whether central nervous system abnormalities detected on brain MRI exist in hyperimmunoglobulin E syndrome and to characterize any identified abnormalities.

PATIENTS AND METHODS

Fifty patients aged from 3 to 52 years (mean: 24 years) with established diagnoses of hyperimmunoglobulin E syndrome had MRI of the brain as part of an hyperimmunoglobulin E syndrome natural history protocol. Abnormalities were described, measured, counted, and mapped. Patient charts were reviewed for neurologic findings and blood pressure measurements.

RESULTS

Focal brain lesions exhibiting high signal intensities on flow-attenuated inversion recovery and on T2-weighted techniques were found in 35 of the 50 patients. The focal hyperintensities were predominantly in the white matter of the cerebral hemispheres, and the number ranged from 2 to >50. The hyperintensities occurred more frequently in adults than in children, and no association with elevated blood pressure was found. Five patients had lacunar infarctions. Chiari type 1 malformations were found in 9 of 50 patients. Two patients had infectious complications presenting on MRI as cerebritis in 1 patient and as a hemorrhagic infarct in the other; both were found on autopsy to be fungal. Neurologic abnormalities were present in 1 patient with a lacunar infarction, the 2 patients with infectious complications, and in 1 patient with a subarachnoid hemorrhage secondary to a berry aneurysm.

CONCLUSIONS

Central nervous system abnormalities are common in hyperimmunoglobulin E syndrome. Focal T2 hyperintensities, not appreciated previously, represent a prominent feature of this rare disease that may assist in diagnosis. The etiology and clinical implications of these abnormalities remain to be investigated.

Human tyrosine kinase 2 deficiency reveals its requisite roles in multiple cytokine signals involved in innate and acquired immunity

Tyrosine kinase 2 (Tyk2) is a nonreceptor tyrosine kinase that belongs to the Janus kinase (Jak) family. Here we identified a homozygous Tyk2 mutation in a patient who had been clinically diagnosed with hyper-IgE syndrome. This patient showed unusual susceptibility to various microorganisms including virus, fungi, and mycobacteria and suffered from atopic dermatitis with elevated serum IgE. The patient's cells displayed defects in multiple cytokine signaling pathways including those for type I interferon (IFN), interleukin (IL)-6, IL-10, IL-12, and IL-23. The cytokine signals were successfully restored by transducing the intact Tyk2 gene. Thus, the Tyk2 deficiency is likely to account for the patient's complex clinical manifestations, including the phenotype of impaired T helper 1 (Th1) differentiation and accelerated Th2 differentiation. This study identifies human Tyk2 deficiency and demonstrates that Tyk2 plays obligatory roles in multiple cytokine signals involved in innate and acquired immunity of humans, which differs substantially from Tyk2 function in mice.

Host genetic factors and mycobacterial infections: lessons from single gene disorders affecting innate and adaptive immunity

This review summarizes the association of increased susceptibility to mycobacterial disease in patients with genetic defects affecting innate and adaptive immunity. The optimum function of CD4 T-cell and macrophage function is critically important for immunity against mycobacteria. Antibody, complement and neutrophil function is not required for effective anti-mycobacterial immunity.