GATA2 deficiency: a protean disorder of hematopoiesis, lymphatics, and immunity.

Haploinsufficiency of the hematopoietic transcription factor GATA2 underlies monocytopenia and mycobacterial infections; dendritic cell, monocyte, B, and natural killer (NK) lymphoid deficiency; familial myelodysplastic syndromes (MDS)/acute myeloid leukemia (AML); and Emberger syndrome (primary lymphedema with MDS). A comprehensive examination of the clinical features of GATA2 deficiency is currently lacking. We reviewed the medical records of 57 patients with GATA2 deficiency evaluated at the National Institutes of Health from January 1, 1992, to March 1, 2013, and categorized mutations as missense, null, or regulatory to identify genotype-phenotype associations. We identified a broad spectrum of disease: hematologic (MDS 84%, AML 14%, chronic myelomonocytic leukemia 8%), infectious (severe viral 70%, disseminated mycobacterial 53%, and invasive fungal infections 16%), pulmonary (diffusion 79% and ventilatory defects 63%, pulmonary alveolar proteinosis 18%, pulmonary arterial hypertension 9%), dermatologic (warts 53%, panniculitis 30%), neoplastic (human papillomavirus+ tumors 35%, Epstein-Barr virus+ tumors 4%), vascular/lymphatic (venous thrombosis 25%, lymphedema 11%), sensorineural hearing loss 76%, miscarriage 33%, and hypothyroidism 14%. Viral infections and lymphedema were more common in individuals with null mutations (P = .038 and P = .006, respectively). Monocytopenia, B, NK, and CD4 lymphocytopenia correlated with the presence of disease (P < .001). GATA2 deficiency unites susceptibility to MDS/AML, immunodeficiency, pulmonary disease, and vascular/lymphatic dysfunction. Early genetic diagnosis is critical to direct clinical management, preventive care, and family screening.

Common severe infections in chronic granulomatous disease.

BACKGROUND: Chronic granulomatous disease (CGD) is due to defective nicotinamide adenine dinucleotide phosphate oxidase activity and characterized by recurrent infections with a limited spectrum of bacteria and fungi as well as inflammatory complications. To understand the impact of common severe infections in CGD, we examined the records of 268 patients followed at a single center over 4 decades. METHODS: All patients had confirmed diagnoses of CGD, and genotype was determined where possible. Medical records were excerpted into a standard format. Microbiologic analyses were restricted to Staphylococcus, Burkholderia, Serratia, Nocardia, and Aspergillus. RESULTS: Aspergillus incidence was estimated at 2.6 cases per 100 patient-years; Burkholderia, 1.06 per 100 patient-years; Nocardia, 0.81 per 100 patient-years; Serratia, 0.98 per 100 patient-years, and severe Staphylococcus infection, 1.44 per 100 patient-years. Lung infection occurred in 87% of patients, whereas liver abscess occurred in 32%. Aspergillus incidence was 55% in the lower superoxide-producing quartiles (quartiles 1 and 2) but only 41% in the higher quartiles (rate ratio, <0.0001). Aspergillus and Serratia were somewhat more common in lower superoxide producing gp91phox deficiency. The median age at death has increased from 15.53 years before 1990 to 28.12 years in the last decade. Fungal infection carried a higher risk of mortality than bacterial infection and was the most common cause of death (55%). Gastrointestinal complications were not associated with either infection or mortality. CONCLUSIONS: Fungal infections remain a major determinant of survival in CGD. X-linked patients generally had more severe disease, and this was generally in those with lower residual superoxide production. Survival in CGD has increased over the years, but infections are still major causes of morbidity and mortality.

Mutations in GATA2 cause human NK cell deficiency with specific loss of the CD56(bright) subset.

Mutations in the transcription factor GATA2 underlie the syndrome of monocytopenia and B- and natural killer (NK)-cell lymphopenia associated with opportunistic infections and cancers. In addition, patients have recurrent and severe viral infections. NK cells play a critical role in mediating antiviral immunity. Human NK cells are thought to mature in a linear fashion, with the CD56(bright) stage preceding terminal maturation to the CD56(dim) stage, considered the most enabled for cytotoxicity. Here we report an NK cell functional defect in GATA2-deficient patients and extend this genetic lesion to what is considered to be the original NK cell-deficient patient. In most cases, GATA2 deficiency is accompanied by a severe reduction in peripheral blood NK cells and marked functional impairment. The NK cells detected in peripheral blood of some GATA2-deficient patients are exclusively of the CD56(dim) subset, which is recapitulated on in vitro NK cell differentiation. In vivo, interferon α treatment increased NK cell number and partially restored function but did not correct the paucity of CD56(bright) cells. Thus, GATA2 is required for the maturation of human NK cells and the maintenance of the CD56(bright) pool in the periphery. Defects in GATA2 are a novel cause of profound NK cell dysfunction.

Impaired T(H)17 cell differentiation in subjects with autosomal dominant hyper-IgE syndrome.

The autosomal dominant hyper-IgE syndrome (HIES, 'Job's syndrome') is characterized by recurrent and often severe pulmonary infections, pneumatoceles, eczema, staphylococcal abscesses, mucocutaneous candidiasis, and abnormalities of bone and connective tissue. Mutations presumed to underlie HIES have recently been identified in stat3, the gene encoding STAT3 (signal transducer and activator of transcription 3) (refs 3, 4). Although impaired production of interferon-gamma and tumour-necrosis factor by T cells, diminished memory T-cell populations, decreased delayed-type-hypersensitivity responses and decreased in vitro lymphoproliferation in response to specific antigens have variably been described, specific immunological abnormalities that can explain the unique susceptibility to particular infections seen in HIES have not yet been defined. Here we show that interleukin (IL)-17 production by T cells is absent in HIES individuals. We observed that ex vivo T cells from subjects with HIES failed to produce IL-17, but not IL-2, tumour-necrosis factor or interferon-gamma, on mitogenic stimulation with staphylococcal enterotoxin B or on antigenic stimulation with Candida albicans or streptokinase. Purified naive T cells were unable to differentiate into IL-17-producing (T(H)17) T helper cells in vitro and had lower expression of retinoid-related orphan receptor (ROR)-gammat, which is consistent with a crucial role for STAT3 signalling in the generation of T(H)17 cells. T(H)17 cells have emerged as an important subset of helper T cells that are believed to be critical in the clearance of fungal and extracellular bacterial infections. Thus, our data suggest that the inability to produce T(H)17 cells is a mechanism underlying the susceptibility to the recurrent infections commonly seen in HIES.

Signal transducer and activator of transcription 1 (STAT1) gain-of-function mutations and disseminated coccidioidomycosis and histoplasmosis.

BACKGROUND: Impaired signaling in the IFN-γ/IL-12 pathway causes susceptibility to severe disseminated infections with mycobacteria and dimorphic yeasts. Dominant gain-of-function mutations in signal transducer and activator of transcription 1 (STAT1) have been associated with chronic mucocutaneous candidiasis. OBJECTIVE: We sought to identify the molecular defect in patients with disseminated dimorphic yeast infections. METHODS: PBMCs, EBV-transformed B cells, and transfected U3A cell lines were studied for IFN-γ/IL-12 pathway function. STAT1 was sequenced in probands and available relatives. Interferon-induced STAT1 phosphorylation, transcriptional responses, protein-protein interactions, target gene activation, and function were investigated. RESULTS: We identified 5 patients with disseminated Coccidioides immitis or Histoplasma capsulatum with heterozygous missense mutations in the STAT1 coiled-coil or DNA-binding domains. These are dominant gain-of-function mutations causing enhanced STAT1 phosphorylation, delayed dephosphorylation, enhanced DNA binding and transactivation, and enhanced interaction with protein inhibitor of activated STAT1. The mutations caused enhanced IFN-γ-induced gene expression, but we found impaired responses to IFN-γ restimulation. CONCLUSION: Gain-of-function mutations in STAT1 predispose to invasive, severe, disseminated dimorphic yeast infections, likely through aberrant regulation of IFN-γ-mediated inflammation.

B-cell activating factor (BAFF) is elevated in chronic granulomatous disease.

Chronic Granulomatous Disease (CGD) is an inherited defect in superoxide production leading to life-threatening infections, granulomas, and, possibly, abnormal immunoglobulin concentrations. We investigated whether factors controlling antibody production, such as B-cell activating factor (BAFF), were altered in CGD. CGD subjects had significantly increased mean (2.3-fold, p < 0.0001) plasma concentrations of BAFF compared to healthy donors. Patients on IFN-γ treatment had significantly higher BAFF concentrations compared with CGD patients not taking IFN-γ (1.6-fold, p < 0.005). Leukocytes from CGD subjects produced normal amounts of BAFF in response to IFN-γ or G-CSF in vitro. Expression of BAFF-R and TACI was significantly reduced on CGD B cells. Elevated BAFF in CGD correlated with CRP (R = 0.44), ESR (R = 0.49), and IgM (R = 0.47) and increased rapidly in healthy subjects following intravenous endotoxin administration. These findings suggest that elevated BAFF in CGD subjects and healthy donors is a consequence of acute and chronic inflammation.

Mutations in GATA2 are associated with the autosomal dominant and sporadic monocytopenia and mycobacterial infection (MonoMAC) syndrome.

The syndrome of monocytopenia, B-cell and NK-cell lymphopenia, and mycobacterial, fungal, and viral infections is associated with myelodysplasia, cytogenetic abnormalities, pulmonary alveolar proteinosis, and myeloid leukemias. Both autosomal dominant and sporadic cases occur. We identified 12 distinct mutations in GATA2 affecting 20 patients and relatives with this syndrome, including recurrent missense mutations affecting the zinc finger-2 domain (R398W and T354M), suggesting dominant interference of gene function. Four discrete insertion/deletion mutations leading to frame shifts and premature termination implicate haploinsufficiency as a possible mechanism of action as well. These mutations were found in hematopoietic and somatic tissues, and several were identified in families, indicating germline transmission. Thus, GATA2 joins RUNX1 and CEBPA not only as a familial leukemia gene but also as a cause of a complex congenital immunodeficiency that evolves over decades and combines predisposition to infection and myeloid malignancy.

Sharp decline in rates of community respiratory viral detection among patients at the National Institutes of Health Clinical Center during the coronavirus disease 2019 (COVID-19) pandemic.

OBJECTIVES: To analyze the frequency and rates of community respiratory virus infections detected in patients at the National Institutes of Health Clinical Center (NIHCC) between January 2015 and March 2021, comparing the trends before and during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: We conducted a retrospective study comparing frequency and rates of community respiratory viruses detected in NIHCC patients between January 2015 and March 2021. Test results from nasopharyngeal swabs and washes, bronchoalveolar lavages, and bronchial washes were included in this study. Results from viral-challenge studies and repeated positives were excluded. A quantitative data analysis was completed using cross tabulations. Comparisons were performed using mixed models, applying the Dunnett correction for multiplicity. RESULTS: Frequency of all respiratory pathogens declined from an annual range of 0.88%-1.97% between January 2015 and March 2020 to 0.29% between April 2020 and March 2021. Individual viral pathogens declined sharply in frequency during the same period, with no cases of influenza A/B orparainfluenza and 1 case of respiratory syncytial virus (RSV). Rhino/enterovirusdetection continued, but with a substantially lower frequency of 4.27% between April 2020 and March 2021, compared with an annual range of 8.65%-18.28% between January 2015 and March 2020. CONCLUSIONS: The decrease in viral respiratory infections detected in NIHCC patients during the pandemic was likely due to the layered COVID-19 prevention and mitigation measures implemented in the community and the hospital. Hospitals should consider continuing the use of nonpharmaceutical interventions in the future to prevent nosocomial transmission of respiratory viruses during times of high community viral load.

A novel STAT1 mutation associated with disseminated mycobacterial disease.

STAT1 is a key component of Interferon (IFN)-γ and IFN-α signaling and mediates protection against mycobacteria, fungal, viral infections, and cancer. Dominant negative inhibitory as well as gain of function heterozygous STAT1 mutations demonstrate that IFN-γ driven cellular responses need to be tightly regulated to control infections. We describe an autosomal dominant mutation in the SH2 domain of STAT1 that disrupts protein phosphorylation, c.1961T>A (M654K). The mutant allele does not permit STAT1 phosphorylation, and impairs STAT1 phosphorylation of the wild type allele. Protein dimerization is preserved but DNA binding activity, IFN-γ driven GAS-luciferase activity, and expression of IFN-γ target genes are reduced. IFN-α driven ISRE response, but not IFN-α driven GAS response, are preserved when cells are co-transfected with wild type and the mutant STAT1 constructs. M654K exerts a dominant negative effect on IFN-γ related immunity and is recessive for IFN-α induced immune function.

Autosomal dominant and sporadic monocytopenia with susceptibility to mycobacteria, fungi, papillomaviruses, and myelodysplasia.

We identified 18 patients with the distinct clinical phenotype of susceptibility to disseminated nontuberculous mycobacterial infections, viral infections, especially with human papillomaviruses, and fungal infections, primarily histoplasmosis, and molds. This syndrome typically had its onset in adulthood (age range, 7-60 years; mean, 31.1 years; median, 32 years) and was characterized by profound circulating monocytopenia (mean, 13.3 cells/microL; median, 14.5 cells/microL), B lymphocytopenia (mean, 9.4 cells/microL; median, 4 cells/microL), and NK lymphocytopenia (mean, 16 cells/microL; median, 5.5 cells/microL). T lymphocytes were variably affected. Despite these peripheral cytopenias, all patients had macrophages and plasma cells at sites of inflammation and normal immunoglobulin levels. Ten of these patients developed 1 or more of the following malignancies: 9 myelodysplasia/leukemia, 1 vulvar carcinoma and metastatic melanoma, 1 cervical carcinoma, 1 Bowen disease of the vulva, and 1 multiple Epstein-Barr virus(+) leiomyosarcoma. Five patients developed pulmonary alveolar proteinosis without mutations in the granulocyte-macrophage colony-stimulating factor receptor or anti-granulocyte-macrophage colony-stimulating factor autoantibodies. Among these 18 patients, 5 families had 2 generations affected, suggesting autosomal dominant transmission as well as sporadic cases. This novel clinical syndrome links susceptibility to mycobacterial, viral, and fungal infections with malignancy and can be transmitted in an autosomal dominant pattern.

Analysis of adhesion molecules, target cells, and role of IL-2 in human FOXP3+ regulatory T cell suppressor function.

FOXP3(+) regulatory T cells (Tregs) are central to the maintenance of self-tolerance and immune homeostasis. The mechanisms of action and cellular targets for Treg-mediated suppression remain controversial. The critical adhesion molecules utilized by Tregs for the interaction with their target cells have not been well characterized. We show that human CD4(+)FOXP3(+)CD25(high) cells (hTregs) suppress the activation of mouse responders as efficiently as mouse Tregs. LFA-1 (CD11a/CD18) on the hTregs is critical for their suppressor function, since suppression can be reversed with blocking anti-hCD11a or anti-hCD18 mAb. Tregs from patients with LFA-1 deficiency fail to suppress human and mouse responders. Mouse CD4(+) T cells deficient in ICAM-1 can be suppressed by hTregs, indicating that the hTregs target mouse dendritic cells (DCs) through the binding of human LFA-1 to mouse ICAM-1. Coculture of mouse DCs with hTregs, but not hTregs from LFA-1-deficient patients, prevented the up-regulation of CD80/CD86 on the DCs and their capacity to activate responder T cells. Lastly, IL-2 is not required for hTreg suppressor function under optimal stimulatory condition and IL-2 consumption plays no role in hTreg-mediated suppression. Taken together, one of the mechanisms of Treg-mediated suppression functions across species and mediates an LFA-1/ICAM-1-dependent interaction between Tregs and DCs.

Plasmid Dissemination and Selection of a Multidrug-Resistant Klebsiella pneumoniae Strain during Transplant-Associated Antibiotic Therapy.

Antibiotics, which are used both to prevent and to treat infections, are a mainstay therapy for lifesaving procedures such as transplantation. For this reason, and many others, increased antibiotic resistance among human-associated pathogens, such as the carbapenem-resistant Enterobacteriaceae species, is of grave concern. In this study, we report on a hematopoietic stem cell transplant recipient in whom cultures detected the emergence of carbapenem resistance and spread across five strains of bacteria that persisted for over a year. Carbapenem resistance in Citrobacter freundii, Enterobacter cloacae, Klebsiella aerogenes, and Klebsiella pneumoniae was linked to a pair of plasmids, each carrying the Klebsiella pneumoniae carbapenemase gene (blaKPC). Surveillance cultures identified a carbapenem-susceptible strain of Citrobacter freundii that may have become resistant through horizontal gene transfer of these plasmids. Selection of a multidrug-resistant Klebsiella pneumoniae strain was also detected following combination antibiotic therapy. Here we report a plasmid carrying the blaKPC gene with broad host range that poses the additional threat of spreading to endogenous members of the human gut microbiome.IMPORTANCE Antibiotic-resistant bacteria are a serious threat to medically fragile patient populations. The spread of antibiotic resistance through plasmid-mediated mechanisms is of grave concern as it can lead to the conversion of endogenous patient-associated strains to difficult-to-treat pathogens.