Exuberant inflammation in nicotinamide adenine dinucleotide phosphate-oxidase-deficient mice after allogeneic marrow transplantation

Cellular Therapies in Chronic Granulomatous Disease

Allogeneic hematopoietic stem cell transplantation (HSCT) has become the main curative treatment in patients with chronic granulomatous disease (CGD). CGD is caused by inherited defects of the phagolysomal NADPH-oxidase, leading to a lifelong propensity for invasive infections and granulomatous inflammation. After successful allogeneic HSCT, chronic infections and inflammation resolve and quality-of-life improves. Favorable long-term outcome after HSCT is dependent on the prevention of primary and secondary graft failure (GF), including falling myeloid donor chimerism (DC) below 10 %, and chronic graft-vs.-host-disease (cGVHD). The risk of GF and GvHD increases with the use of HLA-incompatible donors and this may outweigh the benefits of HSCT, mainly in patients with severe co-morbidities and in asymptomatic patients with residual NADPH-oxidase function. Seventeen scientific papers have reported on a total of 386 CGD-patients treated by HSCT with HLA-matched family/sibling (MFD/MSD), 9/10-/10/10-matched-unrelated volunteer (MUD) and cord blood donors. The median OS/EFS-rate of these 17 studies was 91 and 82%, respectively. The median rates of GF, cGVHD and de-novo autoimmune diseases were 14, 10, and 12%, respectively. Results after MFD/MSD and 10/10-MUD-transplants were rather similar, but outcome in adults with significant co-morbidities and after transplants with 9/10 HLA-MUD were less successful, mainly due to increased GF and chronic GVHD. Transplantation protocols using T-cell depleted haploidentical donors with post-transplant cyclophosphamide or TCR-alpha/beta depletion have recently reported promising results. Autologous gene-therapy after lentiviral transduction of HSC achieved OS/EFS-rates of 78/67%, respectively. Careful retrospective and prospective studies are mandatory to ascertain the most effective cellular therapies in patients with CGD.

Myeloablative transplantation using either cord blood or bone marrow leads to immune recovery, high long-term donor chimerism and excellent survival in chronic granulomatous disease

The curative potential of hematopoietic stem cell transplantation in patients with chronic granulomatous disease depends on availability of a suitable donor, successful donor engraftment, and maintenance of long-term donor chimerism. Twelve consecutive children (median age, 59.5 months; range, 8-140 months) with severe chronic granulomatous disease (serious bacterial/fungal infections pretransplantation; median, 3; range, 2-9) received myeloablative hematopoietic stem cell transplantation using sibling bone marrow ([SibBM]; n = 5), unrelated cord blood (UCB; n = 6), and sibling cord blood (n = 1) at our center between 1997 and 2010. SibBM and sibling cord blood were HLA matched at 6/6, whereas UCB were 5/6 (n = 5) or 6/6 (n = 1). Recipients of SibBM were conditioned with busulfan and cyclophosphamide ± anti-thymocyte globulin (ATG), whereas 6 of 7 cord blood recipients received fludarabine/busulfan/cyclophosphamide/ATG. Seven patients received granulocyte-colony stimulating factor-mobilized granulocyte transfusions from directed donors. The first 2 UCB recipients had primary graft failure but successfully underwent retransplantation with UCB. Highest acute graft-versus-host disease was grade III (n = 1). Extensive chronic graft-vs-host disease developed in 3 patients. All patients are alive with median follow-up of 70.5 months (range, 12-167 months) with high donor chimerism (>98%, n = 10; 94%, n = 1; and 92%, n = 1). Myeloablative hematopoietic stem cell transplantation led to correction of neutrophil dysfunction, durable donor chimerism, excellent survival, good quality of life, and low incidence of graft-vs-host disease regardless of graft source.

Hematopoietic stem cell transplantation for chronic granulomatous disease

Chronic granulomatous disease (CGD) is a primary immunodeficiency disease that is caused by the lack of 1 of 5 subunits of the superoxide-producing nicotinamide adenine dinucleotide phosphate oxidase of neutrophils, macrophages, and eosinophils. Allogeneic hematopoietic stem cell transplantation (HSCT) is currently the only curative treatment for CGD and can be offered to selected patients. Improved outcome with supportive care and high clinical variability in the disease course, however, make selection of eligible patients for HSCT difficult. This article addresses recent progress in HSCT for CGD, delineates present limitations, and points to future developments.

The production of reactive oxygen species in peripheral blood neutrophils is modulated by airway mucous

Neutrophils are a major source of reactive oxygen species (ROS). The role of airway mucous on ROS production is unknown. The aim of our study was to investigate the direct influence of bronchoalveolar lavage fluid (BALF) and induced sputum (IS) alone or in combination with chemical/biological stimulus on ROS production in peripheral blood neutrophils during chronic obstructive pulmonary disease (COPD). Neutrophils were isolated from peripheral blood of 47 patients with moderate COPD and 14 healthy individuals (HI). BALF/RPMI (1:1) or IS/RPMI (1:1) from COPD patients were used to stimulate neutrophils alone or in combination with phorbolmyristate- acetate (PMA) (0.1–30 nM) or Staphylococcus aureus bacteria (0.7–500 bact/neutrophil). Relative generation of ROS was measured flow cytometrically. BALF/RPMI and in combination with relatively low PMA or all bacteria concentrations stimulated ROS; while, combination with relatively high PMA concentrations suppressed ROS in of COPD patients and HI. IS/RPMI and its combination with PMA inhibited ROS generation in both groups; whereas, IS stimulated or had a tendency to stimulate ROS production with relatively high bacteria concentrations. In conclusion, BALF and IS directly or in combination with chemical/biological factors modulated ROS production. This effect was stronger in neutrophils from COPD patients and depended on chemical/biological stimulus intensity.

Genetic deficiency of NADPH oxidase does not diminish, but rather enhances, LPS-induced acute inflammatory responses in vivo

Reactive oxygen species (ROS) and oxidative stress are thought to play a central role in the etiology of cell dysfunction and tissue damage in sepsis. However, there is limited and controversial evidence from in vivo studies that ROS mediate cell signaling processes that elicit acute inflammatory responses during sepsis. Because NADPH oxidase is one of the main cellular sources of ROS, we investigated the role of this enzyme in lipopolysaccharide (LPS)-induced acute inflammation in vivo, utilizing mice deficient in the gp91(phox) or p47(phox) subunits of NADPH oxidase. Age-and body weight-matched C57BL/6J wild-type (WT) and gp91(phox-/-) and p47(phox-/-) mice were injected ip with 50 microg LPS or saline vehicle and sacrificed at various time points up to 24 h. We found that LPS-induced acute inflammatory responses in serum and tissues were not significantly diminished in gp91(phox-/-) and p47(phox-/-) mice compared to WT mice. Rather, genetic deficiency of NADPH oxidase was associated with enhanced gene expression of inflammatory mediators and increased neutrophil recruitment to lung and heart. Furthermore, no protection from LPS-induced septic death was observed in either knockout strain. Our findings suggest that NADPH oxidase-mediated ROS production and cellular redox signaling do not promote, but instead limit, LPS-induced acute inflammatory responses in vivo.

Nox enzymes and oxidative stress in the immunopathology of the gastrointestinal tract

Chronic inflammation caused by Helicobacter pylori infection or inflammatory bowel disease (IBD) is closely linked to cancer development. Innate immune abnormalities and enhanced production of reactive oxygen species through a phagocyte NADPH oxidase (Nox2) are key issues in understanding the pathogenesis of inflammation-dependent carcinogenesis. Besides Nox2, functionally distinct homologues (Nox1, Nox3, Nox4, Nox5, Duox1, and Duox2) have been identified. Nox1 and Duox2 are highly expressed in the gastrointestinal tract. Although the functional roles of Nox/Duox in the gastrointestinal tract are still unclear, we will review their potential roles in the gastrointestinal immunopathology, particularly in H. pylori-induced inflammation, IBD, and malignancy.

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.

Successful Low Toxicity Hematopoietic Stem Cell Transplantation for High-Risk Adult Chronic Granulomatous Disease Patients

BACKGROUND

Allogeneic hematopoietic stem cell transplantation for chronic granulomatous disease (CGD) is associated with a significant risk of transplant-related mortality. Adult age, overt infection, and residual inflammatory disease at transplant are major risk factors.

METHODS

Here we report the favorable outcome after bone marrow transplantation in three high-risk adult CGD patients (ages 18, 35, and 39) with severe disease-related complications (overt pneumonia, liver abscess, steroid-dependent granulomatous colitis, diabetes, restrictive lung disease, renal insufficiency, epilepsia). Bone marrow donors were human leukocyte antigen-matched related or unrelated. The conditioning regimen consisted of 2 x 4 mg/kg oral busulphan (d -3, -2), fludarabine 6 x 30 mg/qm (d -7 to -2), rabbit anti-T-cell-globulin (Fresenius) 4 x 10 mg/kg (d -4 to -1). Graft versus host disease prophylaxis consisted of cyclosporine A and mycophenolate-mofetil.

RESULTS

Mean neutrophil and platelet engraftment was observed at day +18.5 and +22.5, respectively. All infectious and inflammatory lesions resolved and restrictive lung disease improved. No signs of grade II-IV acute or chronic graft versus host disease were observed. With a follow-up of 12 to 27 months, all patients are alive and well with full donor chimerism, normalized superoxide production, and documented T- and B-cell function.

CONCLUSION

This modified reduced intensity conditioning protocol is a promising treatment modality for high-risk adult CGD patients.

Gene therapy for chronic granulomatous disease

Chronic granulomatous disease (CGD) is a congenital immune deficiency that is a promising therapeutic target for gene replacement into haematopoietic stem cells (HSCs). CGD results from mutations in any one of four genes encoding subunits of the superoxide-generating NADPH oxidase of phagocytes. Life-threatening, recurrent bacterial and fungal infections, as well as inflammatory granulomas, are the hallmarks of the disease. NADPH oxidase activity can be reconstituted by retroviral- or lentiviral-mediated gene transfer to human CGD marrow in vitro and in xenograft transplant models. Gene transfer studies in knockout mouse models that resemble the human disease suggest that correction of oxidase activity in a minority of phagocytes will be of clinical benefit. Phase I clinical studies in unconditioned CGD patients showed transient expression of small numbers of gene-corrected neutrophils. Areas of research at present include efforts to enhance gene transfer rates into repopulating HSCs using vectors that transduce quiescent cells, and to increase the engraftment of genetically corrected HSCs using non-myeloablative conditioning and drug resistance genes for selection.

Absence of host tumor necrosis factor receptor 1 attenuates manifestations of idiopathic pneumonia syndrome

The interaction of TNF-alpha with TNF receptor 1 (TNFR1) activates several signal transduction pathways that lead to apoptosis or NF-kappa B-dependent inflammation and immunity. We hypothesized that host TNFR1 expression contributes to noninfectious lung injury and inflammation commonly observed after bone marrow transplantation (BMT), termed idiopathic pneumonia syndrome (IPS). C57BL/6 TNFR1-sufficient (TNFR1(+/+)) and -deficient (TNFR1(-/-)) mice were total body irradiated with or without cyclophosphamide conditioning and were given bone marrow plus IPS-inducing donor spleen T cells from B10.BR wild-type mice. TNFR1(-/-) recipient mice exhibited improved early post-BMT survival associated with decreased permeability edema. In addition, the low lung compliance measured in anesthetized, ventilated TNFR1(+/+) mice on day 7 after BMT was restored to baseline during TNFR1 deficiency. Importantly, bronchoalveolar lavage fluid (BALF) inflammatory cells from TNFR1(-/-) vs. TNFR1(+/+) mice generated less nitric oxide (.NO) and nitrating species and exhibited suppressed programmed cell death as assessed using flow cytometry. However, cellular infiltration and levels of proinflammatory cytokines and chemokines were generally higher in BALF collected on day 7 after BMT from TNFR1(-/-) compared with TNFR1(+/+) recipient mice. Our results support a major role of host TNFR1 in regulation of .NO production and lung dysfunction after allogeneic BMT.

Myeloperoxidase deficiency enhances inflammation after allogeneic marrow transplantation

Myeloperoxidase (MPO)-derived oxidants participate in the respiratory antimicrobial defense system but are also implicated in oxidant-mediated acute lung injury. We hypothesized that MPO contributes to lung injury commonly observed after bone marrow transplantation (BMT). MPO-sufficient (MPO+/+) and -deficient (MPO−/−) mice were given cyclophosphamide and lethally irradiated followed by infusion of inflammation-inducing donor spleen T cells at time of BMT. Despite suppressed generation of nitrative stress, MPO−/− recipient mice unexpectedly exhibited accelerated weight loss and increased markers of lung dysfunction compared with MPO+/+ mice. The increased lung injury during MPO deficiency was a result of donor T cell-dependent inflammatory responses because bronchoalveolar lavage fluids (BALF) from MPO−/− mice contained increased numbers of inflammatory cells and higher levels of the proinflammatory cytokine TNF-α and the monocyte chemoattractant protein-1 compared with wild-type mice. Enhanced inflammation in MPO−/− mice was associated with suppressed apoptosis of BALF inflammatory cells. The inflammatory process in MPO−/− recipients was also associated with enhanced necrosis of freshly isolated alveolar type II cells, critical for preventing capillary leak. We conclude that suppressed MPO-derived oxidative/nitrative stress is associated with enhanced lung inflammation and persistent alveolar epithelial injury.

Extra-cellular superoxide promotes T cell expansion through inactivation of nitric oxide

The mechanism and regulation of immunosuppression by nitric oxide (NO) is unclear. Extra-cellular superoxide (EC-O2-) production by NADPH-oxidase (phox) may prevent NO-mediated suppression of T cell proliferation. p47(phox-/-) mice are resistant to experimental allergic encephalomyelitis (EAE), coinciding with enhanced splenic NO activity, but no causal link was established. Here, we demonstrate such link, since p47(phox-/-) mice developed severe EAE by adoptive transfer, but only if NO production during ex vivo donor cell reactivation was inhibited. EC-O2- production increased during cognate T cell reactivation, while inhibition of EC-O2- by exogenous superoxide dismutase enhanced NO activity. By inhibiting NO, EC-O2- production promotes T cell expansion during peripheral immune-response activation, not during tissue inflammation.

T cells express a phagocyte-type NADPH oxidase that is activated after T cell receptor stimulation

T cell receptor (TCR) stimulation induces rapid generation of reactive oxygen species, although the mechanisms for this are unclear. Here we found that T cells expressed a functional phagocyte-type nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. TCR crosslinking induced oxidase activation through the recruitment of preformed Fas ligand and Fas. TCR stimulation induced three separable events generating reactive oxygen species: rapid hydrogen peroxide production independent of Fas or NADPH oxidase; sustained hydrogen peroxide production dependent on both Fas and NADPH oxidase; and delayed superoxide production that was dependent on Fas ligand and Fas yet independent of NADPH oxidase. NADPH oxidase-deficient T cells showed enhanced activation of the kinase Erk and a relative increase in T helper type 1 cytokine secretion. Thus, mature T cells express a phagocyte-type NADPH oxidase that regulates elements of TCR signaling.

Apoptosis and macrophage clearance of neutrophils: regulation by reactive oxygen species

Inflammation is a beneficial host response to foreign challenge involving numerous soluble factors and cell types, including polymorphonuclear granulocytes or neutrophils. Programmed cell death (apoptosis) of neutrophils has been documented in vitro as well as in vivo, and is thought to be important for the resolution of inflammation, as this process allows for engulfment and removal of senescent cells prior to their necrotic disintegration. Studies in recent years have begun to unravel the mechanism of macrophage clearance of apoptotic cells, and evidence has accrued for a critical role of externalization and oxidation of plasma membrane phosphatidylserine, and its subsequent recognition by macrophage receptors, in this process. Activated neutrophils generate vast amounts of reactive oxygen species for the purpose of killing ingested micro-organisms, and these reactive metabolites may also modulate the life-span, as well as the clearance, of the neutrophil itself. This review aims to address the latter topic, as well as to summarize current knowledge on the molecular mechanisms of neutrophil apoptosis and macrophage clearance of these cells at the site of inflammation.