Invasive aspergillosis in two patients with Pearson syndrome

The Reciprocal Interplay between Infections and Inherited Metabolic Disorders

Infections represent the main cause of acute metabolic derangements and/or the worsening of the clinical course of many inherited metabolic disorders (IMDs). The basic molecular mechanisms behind the role of infections in these conditions have not been completely clarified. This review points out the different mechanisms behind the relationship between IMDs and infections, providing an overview of this still-under-investigated area. Classically, infections have been considered as the consequence of a compromised immune system due to a biochemical defect of energy production. An adjunctive pathogenetic mechanism is related to a genetically altered protein-attached glycans composition, due to congenital glycosilation defects. In addition, a dietary regimen with a reduced intake of both micro- and macronutrients can potentially compromise the ability of the immune system to deal with an infection. There is recent pre-clinical evidence showing that during infections there may be a disruption of substrates of various metabolic pathways, leading to further cellular metabolic alteration. Therefore, infective agents may affect cellular metabolic pathways, by mediation or not of an altered immune system. The data reviewed here strongly suggest that the role of infections in many types of IMDs deserves greater attention for a better management of these disorders and a more focused therapeutic approach.

The molecular immunology of human susceptibility to fungal diseases: lessons from single gene defects of immunity

INTRODUCTION

Fungal diseases are a threat to human health. Therapies targeting the fungus continue to lead to disappointing results. Strategies targeting the host response represent unexplored opportunities for innovative treatments. To do so rationally requires the identification and neat delineation of critical mechanistic pathways that underpin human antifungal immunity. The study of humans with single-gene defects of the immune system, i.e. inborn errors of immunity (IEIs), provides a foundation for these paradigms. Areas covered: A systematic literature search in PubMed, Scopus, and abstracts of international congresses was performed to review the history of genetic resistance/susceptibility to fungi and identify IEIs associated with fungal diseases. Immunologic mechanisms from relevant IEIs were integrated with current definitions and understandings of mycoses to establish a framework to map out critical immunobiological pathways of human antifungal immunity. Expert opinion: Specific immune responses non-redundantly govern susceptibility to their corresponding mycoses. Defining these molecular pathways will guide the development of host-directed immunotherapies that precisely target distinct fungal diseases. These findings will pave the way for novel strategies in the treatment of these devastating infections.

Bone marrow features in Pearson syndrome with neonatal onset: A case report and review of the literature

Pearson syndrome (PS) is a rare mitochondrial disorder that usually presents with transfusion-dependent macrocytic anemia, exocrine pancreatic dysfunction, and lactic acidosis. Typical bone marrow (BM) features are vacuolization in hematopoietic progenitors, hypocellularity, and ringed sideroblasts. At the neonatal age, PS may have a variable clinical onset. Moreover, there is little information about BM features at this age and the timing of their presentation. We report a neonatal case of PS that presented with refractory anemia and atypical BM features. We reviewed the BM findings in neonatal-onset PS cases to stress the importance and limitations of BM evaluation at this age.

The emerging role of immune dysfunction in mitochondrial diseases as a paradigm for understanding immunometabolism

Immunometabolism aims to define the role of intermediary metabolism in immune cell function, with bioenergetics and the mitochondria recently taking center stage. To date, the medical literature on mitochondria and immune function extols the virtues of mouse models in exploring this biologic intersection. While the laboratory mouse has become a standard for studying mammalian biology, this model comprises part of a comprehensive approach. Humans, with their broad array of inherited phenotypes, serve as a starting point for studying immunometabolism; specifically, patients with mitochondrial disease. Using this top-down approach, the mouse as a model organism facilitates further exploration of the consequences of mutations involved in mitochondrial maintenance and function. In this review, we will discuss the emerging phenotype of immune dysfunction in mitochondrial disease as a model for understanding the role of the mitochondria in immune function in available mouse models.

Clinical manifestations and enzymatic activities of mitochondrial respiratory chain complexes in Pearson marrow-pancreas syndrome with 3-methylglutaconic aciduria: a case report and literature review

Pearson marrow-pancreas syndrome (PS) is a rare mitochondrial disorder. Impaired mitochondrial respiratory chain complexes (MRCC) differ among individuals and organs, which accounts for variable clinical pictures. A subset of PS patients develop 3-methylglutaconic aciduria (3-MGA-uria), but the characteristic symptoms and impaired MRCC remain unknown. Our patient, a girl, developed pancytopenia, hyperlactatemia, steatorrhea, insulin-dependent diabetes mellitus, liver dysfunction, Fanconi syndrome, and 3-MGA-uria. She died from cerebral hemorrhage at 3 years of age. We identified a novel 5.4-kbp deletion of mitochondrial DNA. The enzymatic activities of MRCC I and IV were markedly reduced in the liver and muscle and mildly reduced in skin fibroblasts and the heart. To date, urine organic acid analysis has been performed on 29 PS patients, including our case. Eight patients had 3-MGA-uria, while only one patient did not. The remaining 20 patients were not reported to have 3-MGA-uria. In this paper, we included these 20 patients as PS patients without 3-MGA-uria. PS patients with and without 3-MGA-uria have similar manifestations. Only a few studies have examined the enzymatic activities of MRCC.

CONCLUSION

No clinical characteristics distinguish between PS patients with and without 3-MGA-uria. The correlation between 3-MGA-uria and the enzymatic activities of MRCC remains to be elucidated.

WHAT IS KNOWN

• The clinical characteristics of patients with Pearson marrow-pancreas syndrome and 3-methylglutaconic aciduria remain unknown.

WHAT IS NEW

• No clinical characteristics distinguish between Pearson marrow-pancreas syndrome patients with and without 3-methylglutaconic aciduria.

Pearson syndrome in the neonatal period: two case reports and review of the literature

Pearson syndrome is a multiorgan mitochondrial cytopathy that results from defective oxidative phosphorylation owing to mitochondrial DNA deletions. Prognosis is severe and death occurs in infancy or early childhood. This article describes 2 cases with a severe neonatal onset of the disease. A review of the literature reveals the atypical presentation of the disease in the neonatal period, which is often overlooked and underdiagnosed.

The neurological evolution of Pearson syndrome: case report and literature review

BACKGROUND

Pearson syndrome (PS) is an uncommon specific syndrome among mitochondrial diseases. It has unique clinical presentations.

AIMS

The purpose of this article is to clarify the neurological evolution, neuroimage findings, molecular genetic analysis and outcomes in PS cases with neurologic manifestations.

METHODS

We described the clinical progress of a female patient who was diagnosed as PS with a novel 6.0 kbp mitochondrial DNA deletion. She had typical clinical features of PS in early infancy followed by multiple organs involvement after the age of 1 year. At age 3, Kearns-Sayre syndrome (KSS) and Leigh syndrome (LS) developed. We also reviewed PS cases reported in the literature and analyzed the neurological evolution.

RESULTS

Total 55 PS cases, including our index case, had been reported. Among them, 11 cases had detailed clinical descriptions in terms of hypotonia, developmental delay, ataxia or tremor. In whom, PS might evolve into KSS and/or LS: three cases evolving into KSS; one case on the transition of KSS; three cases evolve into LS; our index case has both presentations. The neuroimage findings of PS were quite different which might be from normal to specific abnormal findings over the cerebral white matter, cerebellum, basal ganglion and brainstem. Among those cases, the molecular analysis revealed large-scale mitochondrial deletion around 3.1-6.0kbp. The outcome of PS was opposite: either early death before age 4 or survived beyond age 7.

CONCLUSIONS

The neurological features of PS have potential evolution changes that are from normal, mild neurological deficits to special mitochondrial syndromes: KSS and LS. Closely monitoring neurological symptoms, arranging eye fundus examinations and neuroimaging studies in cases with changes of neurological signs are crucial.

Invasive aspergillosis in primary immunodeficiencies

Primary immunodeficiencies are rare and usually first manifest during childhood. Invasive aspergillosis is the leading cause of mortality in chronic granulomatous disease (CGD), reflecting the key role of the phagocyte NADPH oxidase in host defense against opportunistic fungi. Despite interferon-gamma prophylaxis, invasive filamentous fungal infections are a persistent problem in CGD. Key principles of management of fungal infections involve early recognition and aggressive treatment and appropriate surgical debridement of localized disease. Because CGD is a disorder of phagocyte stem cells in which the gene defects are well defined, it is a model disease to evaluate immune reconstitution through stem cell transplantation and gene therapy. Patients with the hyper-IgE syndrome with recurrent infections (Job syndrome) are prone to colonization of lung cavities (pneumatoceles) by Aspergillus species leading to local invasion and rarely disseminated infection. Other primary phagocytic disorders, T-cell disorders, and mitochondrial disorders are uncommonly associated with invasive aspergillosis. Taken together, these rare primary immunodeficiencies highlight the complex coordination of both innate and acquired pathways mediating host defense against Aspergillus infection.