Clinical Studies Of Abnormal Host Defense

National Institute Of Allergy And Infectious Diseases

Investigators

Linked publications, trials & patents

Abstract

(1) Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by mutations in the multicomponent NADPH oxidase (phagocyte oxidase, NOX2) complex. During the past FY, through collaboration with the Neutrophil Monitoring Laboratory (NML) managed by Douglas Kuhns, PhD (Leidos, Inc.), we provided molecular diagnoses using immunodetection of components of the NADPH oxidase for 17 new patients with CGD. Together with previous patients, this brings the CGD cohort available for study at the NIH CC to 525 patients and 333 carriers from 469 families. Insights derived from the study of this large cohort were reported during FY21 in Blood cells, molecules & diseases (Roos et al). (2) Our group continues its clinical studies of the emerging Gram-negative CGD pathogen, Granulibacter bethesdensis. We continue to monitor seropositivity in culture-confirmed patients and patients suspected of having a Granulibacter infection to evaluate our hypothesis that this organism can establish persistent, clinically silent infections. Although rare, reported Granulibacter infections in CGD patients have a case fatality rate of 30% suggesting that more work is required to improve diagnosis and treatment of this pathogen. This year, we have begun whole genome sequencing of 2 clinical isolates. (3) Our protocol, (#10-I-0029 Non-invasive Assessment of Atherosclerosis in Patients with CGD and other Disorders of the Immune System) demonstrated the contribution of NOX2-dependent ROS to the development of increased carotid vessel wall thickness, a preclinical sign of atherosclerosis that is readily detectable using carotid magnetic resonance imaging. During FY21, we concluded our study of preclinical atherosclerosis in carriers of X-linked CGD. X-CGD carriers are generally healthy although lyonization, or X-chromosome inactivation, results in X-CGD carriers having different numbers of normal and CGD-like cells in their circulation. In some cases, where the X-chromosome containing the wild-type allele is inactivated in 90-95% of progenitor cells, the patients can present with a clinical phenotype indistinguishable from CGD. The study of carriers and healthy-age match controls identified no significant correlation of lyonization with vessel wall thickness although, as a group, carriers tended towards having reduced preclinical atherosclerosis. In other clinical studies, we collaborated on a clinical study assessing the natural history of gastrointestinal disease in CGD patients and showed that GI abnormalities are commonly observed on CT in CGD patients. Bowel wall thickening correlates with endoscopic and histopathologic evidence of inflammation. These findings may be used to better facilitate directed endoscopic assessment and histopathologic sampling in patients with CGD and were published in Dig Dis. Sci. 2021. We also collaborated with investigators from the National Cancer Institute on a study evaluating the effect of zotiraciclib on neutrophil function in adult patents with recurrent anaplastic astrocytoma and glioblastoma who demonstrated transient neutropenia as part of therapy. In-depth neutrophil analysis found a significant decrease in absolute neutrophil count and neutrophil reactive oxygen species production 1224 hours after an oral dose of zotiraciclib but both recovered by 72 hours, when the drug plasma concentration became undetected. These transient side effects were not associated with clinical infection and the recommendation was to monitor the patients carefully but continue the studies for clinical efficacy. These data were published in Clinical Cancer Res in 2021. (4) Based on the initial results of our clinical study (10-I-0029, we have been collaborating with investigators at the National Center for Advancing Translational Sciences (NCATS) to identify chemical inhibitors of NOX2. Using a cell line developed by Tom Leto in the LCIM, we developed a lab scale-screening assay for NOX2 activity that then optimized by NCATS for high throughput, robotic screening for inhibitors of NOX2. To date, we have evaluated over 70,000 compounds in primary and secondary screens and are working on variants of lead candidates for further study. Given the high rate of false-positive compounds in the first-generation primary screen, we are actively developing several alternative assays for NOX2 that do not rely on indirect measurements of enzyme activity in intact cells but rather focus either on subunit interactions (binding) that are known to regulate assembly of the active enzyme complex or a highly purified enzyme complex with artificial activators that function as a molecularly defined assay instead of a whole cell. During FY21, we developed assays for other NOX family members (e.g., NOX1, NOX3, NOX4, NOX5) in order to test specificity of these compounds and are working towards developing assays of DUOXes as well. We have also performed studies of wild-type mice and mouse strains that are genetically deficient in various NOX enzymes (NOX1, NOX2, NOX4) to evaluate their contributions to pathogenesis in a model of traumatic brain injury in collaboration with Dr. Dorian McGavern (NINDS). This model has also been used to evaluate lead NOX2 inhibitors and further ongoing experiments to definitively prove the involvement of NOX2 in this process are underway. 5) During FY21, we published our study of the role of plasma gelsolin in controlling cellular activation during inflammation. Plasma gelsolin is produced by the same gene that encodes the cytosolic actin-binding protein, gelsolin, that plays a crucial role in the regulation of cellular morphology and motility. The plasma form (pGSN) differs in that it possesses an additional short polypeptide of unknown function. Studies by other investigators have identified a role for gelsolin in the regulation of inflammation and as a positive contributor to innate defenses. We measured pGSN in plasma from healthy volunteers, clinically stable CGD patients, and X-linked CGD carriers and in sera from 12 CGD patients undergoing bone marrow transplantation. pGSN concentrations were significantly lower in CGD patients without active infection or systemic inflammation compared with healthy control subjects. Following bone marrow transplantations of CGD patients, pGSN concentrations increased. In collaboration with Anthony Suffredini in the NIH CC Critical Care Medicine Department, we also showed that despite the lower levels of pGSN seen in chronically ill patients, we did not detect changes in pGSN over 24 h following intravenous endotoxin (4 ng/kg) that elicited a febrile response suggesting that pGSN may not be an acute phase reactant. These findings were published in Inflammation. As part of our study of gelsolin as a marker of inflammation, we took advantage of the availability of samples from several cohorts of patients infected with SARS-CoV-2 and different degrees of COVID19 disease. We found that although pGSN trended lower in patients with moderate disease, significant reductions in pGSN could be seen with progressively severe disease with lowers levels seen in patients who went on to succum to COVID19. The results of this study were published in JCI Insight.