epiglucan and Granulomatous-Disease--Chronic

Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by genetic defects in leukocyte NADPH oxidase, which has both microbicidal and immunomodulatory roles. Hence, CGD is characterized by recurrent bacterial and fungal infections as well as aberrant inflammation. Fungal cell walls induce neutrophilic inflammation in CGD; yet, underlying mechanisms are incompletely understood. This study investigated the receptors and signaling pathways driving aberrant proinflammatory cytokine production in CGD neutrophils activated by fungal cell walls. Although cytokine responses to β-glucan particles were similar in NADPH oxidase-competent and NADPH oxidase-deficient mouse and human neutrophils, stimulation with zymosan, a more complex fungal particle, induced elevated cytokine production in NADPH oxidase-deficient neutrophils. The dectin-1 C-type lectin receptor, which recognizes β-glucans (1-3), and TLRs mediated cytokine responses by wild-type murine neutrophils. In the absence of NADPH oxidase, fungal pathogen-associated molecular patterns engaged additional collaborative signaling with Mac-1 and TLRs to markedly increase cytokine production. Mechanistically, this cytokine overproduction is mediated by enhanced proximal activation of tyrosine phosphatase SHP2-Syk and downstream Card9-dependent NF-κB and Card9-independent JNK-c-Jun. This activation and amplified cytokine production were significantly decreased by exogenous H

Topics: Animals; Antigens, Fungal; Aspergillus fumigatus; beta-Glucans; Cells, Cultured; Cytokines; Granulomatous Disease, Chronic; Lectins, C-Type; Macrophage-1 Antigen; Mice; Mice, Inbred C57BL; Mice, Knockout; NADPH Oxidase 2; Neutrophil Activation; Neutrophils; NF-kappa B; Pathogen-Associated Molecular Pattern Molecules; Receptor Cross-Talk; Receptors, Pattern Recognition; Signal Transduction

Chronic granulomatous disease (CGD) is a primary immunodeficiency characterized by recurrent infections and a dysregulated inflammatory response. Infection-triggered hemophagocytic lymphohistiocytosis (HLH), which manifests itself as pathologic hyperactive inflammation, has been observed in subjects with CGD. However, there have been no reports of HLH as the initial presentation with subsequent diagnosis of CGD. Furthermore, the primary therapeutic strategy for HLH focuses on immunosuppressive therapies, which limits immune-mediated tissue damage. With immunodeficiency, this therapeutic strategy may worsen the outcome. This article discusses an 8-week-old Hispanic male who presented with fever of unknown origin. The initial diagnostic evaluation demonstrated pathologic hyperactive inflammation, meeting the HLH-2004 diagnostic criteria without an identified infectious etiology. Immunosuppressive therapy was initiated, with subsequent disseminated candida septic shock and sepsis-induced multisystem organ failure. Additional evaluations ultimately established the diagnosis of CGD. We transitioned to an immune-enhancing strategy with granulocyte and immunoglobulin infusions, and intensified antifungal therapies. These interventions ultimately led to the clearance of the fungal infection and the resolution of the hyperactive inflammatory state. This case represents the first reported case of HLH as the presenting finding leading to the subsequent diagnosis of CGD. It serves as a reminder that both immunodeficiency and inflammatory disorders may share features of pathologic hyperactive inflammation and highlights the conundrum that clinicians face when treating HLH in the setting of an unresolved infection. In this case report, we demonstrate that immune-enhancing therapies may aid in the control and the clearance of the infection, thus paradoxically decreasing the pathologic hyperactive inflammatory response.

Topics: beta-Glucans; Combined Modality Therapy; Diagnosis, Differential; Disease Progression; DNA Mutational Analysis; Fever of Unknown Origin; Fungemia; Granulocytes; Granulomatous Disease, Chronic; Humans; Immunization, Passive; Immunosuppressive Agents; Infant; Interferon-gamma; Lymphohistiocytosis, Hemophagocytic; Male; Membrane Glycoproteins; NADPH Oxidase 2; NADPH Oxidases; Opportunistic Infections; Proteoglycans

Chronic granulomatous disease (CGD), a genetic disorder characterized by the absence of a functional phagocyte NADPH oxidase, is a severe immune deficiency. However, non-infectious hyperinflammation is a second hallmark of the disease. In CGD mouse models, sterile hyperinflammation can be induced by A. fumigatus cell wall preparations. In this study, we used subcutaneous injection of microbial cell walls and cell wall components to identify causes of CGD hyperinflammation and to characterize its histological features. Sterile cell wall preparations from fungi (A. fumigatus, C. albicans, S. cerevisiae), but not from bacteria (S. aureus, P. aeruginosa, E. coli), caused prolonged and severe skin inflammation in CGD mice. To identify fungal cell wall elements responsible for this process, we investigated microbial cell wall-derived monosubstances. Injection of beta(1-3)(1-6)-glucan induced severe hyperinflammation in CGD mice, while other fungal cell components [mannan, (1-3) beta-glucan] or bacterial cell wall components (lipopolysaccharide, lipoteichoic acid) caused no or only moderate inflammation. beta-glucan-induced hyperinflammation was predominantly due to a defect in termination of inflammation, as in the initial stage (2 days), the severity of inflammation and the extent of cell death were comparable in wild-type and CGD mice. At later stages (7 days), beta(1-3)(1-6)-glucan-induced inflammation had subsided in wild-type mice. In contrast, CGD mice showed persistent severe inflammation with central necrosis, containing abundant apoptotic and necrotic cells. In summary, branched fungal beta-glucan induces a severe inflammatory reaction in the absence of phagocyte NADPH oxidase. As opposed to the commonly perceived notion that reactive oxygen species are the cause of cell death, our results demonstrate that tissue necrosis can be caused by the absence of a superoxide-producing enzyme.

Topics: Animals; Bacteria; beta-Glucans; Cell Death; Cell Wall; Dermatitis; Disease Models, Animal; Fungi; Granulomatous Disease, Chronic; Injections, Intradermal; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; NADPH Oxidases; Necrosis; Phagocytes; Skin