Benefit assessment of preventive medical check-ups in patients suffering from chronic granulomatous disease (CGD)

Neutrophils confer T cell resistance to myeloid-derived suppressor cell-mediated suppression to promote chronic inflammation

Low-grade chronic inflammation can persist in aging humans unnoticed for years or even decades, inflicting continuous damage that can culminate later in life as organ dysfunction, physical frailty, and some of the most prominent debilitating and deadly age-associated diseases, including rheumatoid arthritis, diabetes, heart disease, and cancer. Despite the near universal acceptance of these associations, the mechanisms underlying unresolved inflammation remain poorly understood. In this study, we describe a novel inducible method to examine systemic chronic inflammation using susceptible animal models. Induced inflammation results in unresolved innate cellular responses and persistence of the same serum proinflammatory molecules used as diagnostic biomarkers and therapeutic targets for chronic inflammation in humans. Surprisingly, we found long-term persistence of an inflammation-associated neutrophil cell population constitutively producing the proinflammatory IFN-γ cytokine, which until now has only been detected transiently in acute inflammatory responses. Interestingly, these cells appear to confer T cell resistance to the otherwise potent anti-inflammatory function of myeloid-derived suppressor cells, revealing a novel mechanism for the maintenance of chronic inflammatory responses over time. This discovery represents an attractive target to resolve inflammation and prevent the inflammation-induced pathologies that are of critical concern for the well-being of the aging population.

P67-phox (NCF2) lacking exons 11 and 12 is functionally active and leads to an extremely late diagnosis of chronic granulomatous disease (CGD)

Two brothers in their fifties presented with a medical history of suspected fungal allergy, allergic bronchopulmonary aspergillosis, alveolitis, and invasive aspergillosis and pulmonary fistula, respectively. Eventually, after a delay of 50 years, chronic granulomatous disease (CGD) was diagnosed in the index patient. We found a new splice mutation in the NCF2 (p67-phox) gene, c.1000+2T→G, that led to several splice products one of which lacked exons 11 and 12. This deletion was in frame and allowed for remarkable residual NADPH oxidase activity as determined by transduction experiments using a retroviral vector. We conclude that p67-phox which lacks the 34 amino acids encoded by the two exons can still exert considerable functional activity. This activity can partially explain the long-term survival of the patients without adequate diagnosis and treatment, but could not prevent progressing lung damage.

Doença granulomatosa crônica: diagnóstico no primeiro episódio infeccioso

OBJETIVO: Relatar caso ilustrativo de doença granulomatosa crônica cujo diagnóstico ocorreu durante o aparecimento do primeiro episódio infeccioso, colaborando com a iniciativa do Brazilian Group for Immunodeficiency para a sensibilização do pediatra geral em relação ao diagnóstico precoce das imunodeficiências primárias, o que está associado a melhor qualidade de vida e maior sobrevida desses indivíduos. DESCRIÇÃO DE CASO: Paciente do sexo masculino, 39 dias de vida, admitido em pronto-socorro pediátrico por febre alta há cinco dias e irritabilidade. No dia seguinte, observou-se abscesso cervical, isolando-se Staphylococcus aureus comunitário. Durante a internação, ocorreram outros abscessos superficiais e em cadeias ganglionares profundas, além de resposta lenta aos antimicrobianos. Solicitou-se investigação para imunodeficiências, que confirmou a hipótese de doença granulomatosa crônica por quantificação dos ânions superóxido e teste de redução do nitrobluetetrazolio. Paciente foi encaminhado a serviço especializado, no qual identificou-se doador de medula óssea compatível, realizando-se o transplante seis meses após o diagnóstico. Quatro meses após o transplante, ocorreu normalização do burst oxidativo, indicando sucesso. COMENTÁRIOS: O paciente mostrou apresentação típica da doença, o que permitiu seu diagnóstico por pediatras gerais já na primeira infecção, tendo como consequência o acompanhamento por especialistas em imunodeficiências primárias, a introdução da profilaxia antimicrobiana e a procura bem sucedida de doador de medula HLA-compatível.

Alu-repeat-induced deletions within the NCF2 gene causing p67-phox-deficient chronic granulomatous disease (CGD)

Mutations that impair expression or function of the components of the phagocyte NADPH oxidase complex cause chronic granulomatous disease (CGD), which is associated with life-threatening infections and dysregulated granulomatous inflammation. In five CGD patients from four consanguineous families of two different ethnic backgrounds, we found similar genomic homozygous deletions of 1,380 bp comprising exon 5 of NCF2, which could be traced to Alu-mediated recombination events. cDNA sequencing showed in-frame deletions of phase zero exon 5, which encodes one of the tandem repeat motifs in the tetratricopeptide (TPR4) domain of p67-phox. The resulting shortened protein (p67Delta5) had a 10-fold reduced intracellular half-life and was unable to form a functional NADPH oxidase complex. No dominant negative inhibition of oxidase activity by p67Delta5 was observed. We conclude that Alu-induced deletion of the TPR4 domain of p67-phox leads to loss of function and accelerated degradation of the protein, and thus represents a new mechanism causing p67-phox-deficient CGD.

Chronic granulomatous disease (CGD) mimicking neoplasms: a suspected mediastinal teratoma unmasking as thymic granulomas due to X-linked CGD, and 2 related cases

Patients with chronic granulomatous disease (CGD) suffer from severe bacterial and fungal infections and deregulated inflammation, which are often associated with granuloma formation. We describe a 2-year-old boy who was seemingly healthy at the age of 1 year when a conventional chest radiograph was taken to exclude pulmonary aspiration of a piece of apple. Incidentally, a space-occupying mediastinal mass was revealed that was further evaluated by magnetic resonance imaging. Varying solid and also cystic, septated parts of the mass could be discerned and it was considered to be a teratoma. Removal of the mass by surgery was arduous because of adhesiveness to surrounding areas and led to severe complications. Unexpectedly, histopathologic examination revealed massive acute granulomatous inflammation with liquefied thymic cysts. X-linked CGD was subsequently diagnosed by a dihydrorhodamine 123 assay and sequencing of the CYBB gene (hotspot mutation c.742-743insA). This is the third example that we are aware of, where CGD granulomas were mistaken for neoplasms. The other 2 patients were initially believed to have tumors of the stomach and the urinary bladder, respectively. All patients initially received inadequate treatment. We discuss possible strategies to avoid such tragic confusions.

Modern management of chronic granulomatous disease

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency disorder of phagocytic cells resulting in failure to kill a characteristic spectrum of bacteria and fungi and in defective degradation of inflammatory mediators with concomitant granuloma formation. Current prophylaxis with trimethoprim-sulfamethoxazole, itraconazole and in selected cases additional interferon gamma is efficient, but imperfect. A significant recent progress towards new antibiotic (e.g. linezolid) and antifungal (e.g. voriconazole and posaconazole) therapy will allow survival of most patients into adulthood. Adolescent and adult CGD is increasingly characterized by inflammatory complications, such as granulomatous lung and inflammatory bowel disease, requiring immunosupressive therapy. Allogeneic haematopoietic stem cell transplantation from a human leucocyte antigen identical donor is currently the only proven curative treatment for CGD and can be offered to the selected patients. Gene-replacement therapy for patients lacking a suitable stem cell donor is still experimental and faces major obstacles and risks. However, it may offer some transitory benefits and has helped in a few cases to overcome life-threatening infections.

Gene therapy for chronic granulomatous disease

Patients with chronic granulomatous disease (CGD) cannot generate reactive oxygen metabolites, and suffer from severe recurrent infections and dysregulated inflammation. Haematopoietic stem cell transplantation is the only established option for definitive cure for patients with a suitable donor and is indicated when conventional prophylaxis and therapy with antimicrobial medication fail. Gene therapy has the potential to cure CGD, and several clinical trials have been conducted since 1997. Whereas initial studies resulted in low and short-term engraftment of CGD-corrected cells, recent trials demonstrated clinical benefit when engraftment was enhanced by busulfan conditioning prior to infusion of gene-corrected cells. However, the progress in gene therapy has been hampered by the appearance of insertional mutagenesis causing leukaemia in a trial for patients with X-linked severe combined immunodeficiency and by the emergence of dominant clones in a recent trial for the X-linked form of CGD. These findings stimulated the development of modified vector systems that demonstrate reduced genotoxicity in vitro and in animal models. New gene therapy protocols that allow efficient gene transfer and durable expression but limit the risk for insertional mutagenesis are envisioned to become an important therapeutic option for patients with CGD.

Successful unrelated bone marrow transplantation in a child with chronic granulomatous disease complicated by pulmonary and cerebral granuloma formation

We report on a 6-year-old boy with chronic granulomatous disease (CGD) complicated by chronic inflammatory reactions with formation of large pulmonary granuloma as well as intracerebral lesions. Bone marrow transplantation (BMT) from an unrelated donor led to stable reconstitution, to rapid resolution of pulmonary granuloma, and to rapid resolution of intracerebral lesions.

Chronic granulomatous disease (CGD) and complete myeloperoxidase deficiency both yield strongly reduced dihydrorhodamine 123 test signals but can be easily discerned in routine testing for CGD

BACKGROUND

The flow cytometric dihydrorhodamine 123 (DHR) assay is used as a screening test for chronic granulomatous disease (CGD), but complete myeloperoxidase (MPO) deficiency can also lead to a strongly decreased DHR signal. Our aim was to devise simple laboratory methods to differentiate MPO deficiency (false positive for CGD) and NADPH oxidase abnormalities (true CGD).

METHODS

We measured NADPH-oxidase and MPO activity in neutrophils from MPO-deficient patients, CGD patients, NADPH-oxidase-transfected K562 cells and cells with inhibited and substituted MPO.

RESULTS

Eosinophils from MPO-deficient individuals retain eosinophilic peroxidase and therefore generate a normal DHR signal. The addition of recombinant human MPO enhances the DHR signal when simply added to a suspension of MPO-deficient cells but not when added to NADPH-oxidase-deficient (CGD) cells. Lucigenin-enhanced chemiluminescence (LCL) is increased in neutrophils from MPO-deficient patients, whereas neutrophils from patients with CGD show a decreased response.

CONCLUSIONS

A false-positive result caused by MPO deficiency can be easily ascertained because, unlike cells from a CGD patient, cells from MPO-deficient patients (a) contain functionally normal eosinophils, (b) show a significant enhancement of the DHR signal following addition of rhMPO, and (c) generate a strong LCL signal.

A splice-supporting intronic mutation in the last bp position of a cryptic exon within intron 6 of the CYBB gene induces its incorporation into the mRNA causing chronic granulomatous disease (CGD)

Chronic granulomatous disease (CGD) is caused by a defect in both the host's defenses and its regulation of inflammation normally provided by phagocytes and other leukocytes. As in the case described here, it is not uncommon that CGD patients are diagnosed late, only after organ-damaging manifestations have already progressed. In this patient, we found that CGD arose due to a splice-supporting mutation in the last position of a cryptic exon towards the middle of intron 6 of the CYBB (gp91-phox) gene. The mutation led to the insertion of 56 bp into most of the CYBB mRNA of leukocytes causing a frame shift and a premature stop codon. The normal cryptic exon was also found to be mildly active in some tissues other than leukocytes in healthy donors, to be conserved in many primates, and to a lesser degree in other mammals. Some sequence similarity suggests that the cryptic exon may have originated from a mammalian interspersed repetitive (MIR) element. Taken together, we clarify an unusual disease-causing mutation, indicate its evolutionary background and emphasize the importance of a timely diagnosis of CGD.