Dominant activating RAC2 mutation with lymphopenia, immunodeficiency, and cytoskeletal defects.

Ras-related C3 botulinum toxin substrate 2 (RAC2), through interactions with reduced NAD phosphate oxidase component p67 phox , activates neutrophil superoxide production, whereas interactions with p21-activated kinase are necessary for fMLF-induced actin remodeling. We identified 3 patients with de novo RAC2[E62K] mutations resulting in severe T- and B-cell lymphopenia, myeloid dysfunction, and recurrent respiratory infections. Neutrophils from RAC2[E62K] patients exhibited excessive superoxide production, impaired fMLF-directed chemotaxis, and abnormal macropinocytosis. Cell lines transfected with RAC2[E62K] displayed characteristics of active guanosine triphosphate (GTP)-bound RAC2 including enhanced superoxide production and increased membrane ruffling. Biochemical studies demonstrated that RAC2[E62K] retains intrinsic GTP hydrolysis; however, GTPase-activating protein failed to accelerate hydrolysis resulting in prolonged active GTP-bound RAC2. Rac2+/E62K mice phenocopy the T- and B-cell lymphopenia, increased neutrophil F-actin, and excessive superoxide production seen in patients. This gain-of-function mutation highlights a specific, nonredundant role for RAC2 in hematopoietic cells that discriminates RAC2 from the related, ubiquitous RAC1.

A unified metric of human immune health.

Immunological health has been challenging to characterize but could be defined as the absence of immune pathology. While shared features of some immune diseases and the concept of immunologic resilience based on age-independent adaptation to antigenic stimulation have been developed, general metrics of immune health and its utility for assessing clinically healthy individuals remain ill defined. Here we integrated transcriptomics, serum protein, peripheral immune cell frequency and clinical data from 228 patients with 22 monogenic conditions impacting key immunological pathways together with 42 age- and sex-matched healthy controls. Despite the high penetrance of monogenic lesions, differences between individuals in diverse immune parameters tended to dominate over those attributable to disease conditions or medication use. Unsupervised or supervised machine learning independently identified a score that distinguished healthy participants from patients with monogenic diseases, thus suggesting a quantitative immune health metric (IHM). In ten independent datasets, the IHM discriminated healthy from polygenic autoimmune and inflammatory disease states, marked aging in clinically healthy individuals, tracked disease activities and treatment responses in both immunological and nonimmunological diseases, and predicted age-dependent antibody responses to immunizations with different vaccines. This discriminatory power goes beyond that of the classical inflammatory biomarkers C-reactive protein and interleukin-6. Thus, deviations from health in diverse conditions, including aging, have shared systemic immune consequences, and we provide a web platform for calculating the IHM for other datasets, which could empower precision medicine.

Clinical, Imaging, and Laboratory Findings in Patients With GATA2 Deficiency Presenting With Early-Onset Ischemic Stroke.

OBJECTIVE: The purpose of this study was to characterize the clinical, laboratory, and imaging findings of 10 patients with GATA2 deficiency who presented with early-onset ischemic stroke. METHODS: A retrospective chart review was conducted on a 127-patient cohort enrolled in the Natural History Study of GATA2 Deficiency and Related Disorders protocol at NIH between 2013 and 2021. All patients had a genetically confirmed GATA2 deficiency. Patients were included if they had evidence of an ischemic stroke through clinical evaluation and neuroimaging. Stroke diagnosis was confirmed through brain magnetic resonance imaging and/or CT. RESULTS: Ten patients between the ages of 15 and 38 years (4 males and 6 females) were identified with at least one ischemic stroke while 6 patients experienced recurrent strokes (7.9% overall, 10/127). Stroke etiology varied and included small vessel (n = 4), large vessel (n = 1), cardioembolic (n = 1), and undetermined (n = 4). Nine patients had lupus anticoagulant, and 2 patients had a history of recurrent deep vein thrombosis. DISCUSSION: We describe the clinical, laboratory, and imaging findings of 10 patients with GATA2 deficiency younger than 40 years who suffered one or more ischemic strokes , suggesting a link between GATA2 deficiency and stroke. This report emphasizes the need for further research to understand this unique vulnerability within this patient population.

Multiomics integration of 22 immune-mediated monogenic diseases reveals an emergent axis of human immune health.

Monogenic diseases are often studied in isolation due to their rarity. Here we utilize multiomics to assess 22 monogenic immune-mediated conditions with age- and sex-matched healthy controls. Despite clearly detectable disease-specific and "pan-disease" signatures, individuals possess stable personal immune states over time. Temporally stable differences among subjects tend to dominate over differences attributable to disease conditions or medication use. Unsupervised principal variation analysis of personal immune states and machine learning classification distinguishing between healthy controls and patients converge to a metric of immune health (IHM). The IHM discriminates healthy from multiple polygenic autoimmune and inflammatory disease states in independent cohorts, marks healthy aging, and is a pre-vaccination predictor of antibody responses to influenza vaccination in the elderly. We identified easy-to-measure circulating protein biomarker surrogates of the IHM that capture immune health variations beyond age. Our work provides a conceptual framework and biomarkers for defining and measuring human immune health.

Hematopoietic Cell Transplantation and Outcomes Related to Human Papillomavirus Disease in GATA2 Deficiency.

GATA2 deficiency is a bone marrow failure syndrome effectively treated with hematopoietic cell transplantation (HCT), which also addresses the predisposition to many infections (prominently mycobacterial). However, many GATA2-deficient persons who come to HCT also have prevalent and refractory human papilloma virus disease (HPVD), which can be a precursor to cancer. We analyzed 75 HCT recipients for the presence of HPVD to identify patient characteristics and transplantation results that influence HPVD outcomes. We assessed the impact of cellular recovery and iatrogenic post-transplantation immunosuppression, as per protocol (PP) or intensified/prolonged (IP) graft-versus-host disease (GVHD) prophylaxis or treatment, on the persistence or resolution of HPVD. Our experience with 75 HCT recipients showed a prevalence of 49% with anogenital HPVD, which was either a contributing or primary factor in the decision to proceed to HCT. Of 24 recipients with sufficient follow-up, 13 had resolution of HPVD, including 8 with IP and 5 with PP. Eleven recipients had persistent HPVD, including 5 with IP and 6 with PP immunosuppression. No plausible cellular recovery group (natural killer cells or T cells) showed a significant difference in HPV outcomes. One recipient died of metastatic squamous cell carcinoma, presumably of anogenital origin, at 33 months post-transplantation after prolonged immunosuppression for chronic GVHD. Individual cases demonstrate the need for continued aggressive monitoring, especially in the context of disease prevalent at transplantation or prior malignancy. HCT proved curative in many cases in which HPVD was refractory and recurrent prior to transplantation, supporting a recommendation that HPVD should be considered an indication rather than contraindication to HCT, but post-transplantation monitoring should be prolonged with a high level of vigilance for new or recurrent HPVD.

Sequencing of RNA in single cells reveals a distinct transcriptome signature of hematopoiesis in GATA2 deficiency.

Constitutional GATA2 deficiency caused by heterozygous germline GATA2 mutations has a broad spectrum of clinical phenotypes, including systemic infections, lymphedema, cytopenias, and myeloid neoplasms. Genotype-phenotype correlation is not well understood mechanistically in GATA2 deficiency. We performed whole transcriptome sequencing of single hematopoietic stem and progenitor cells from 8 patients, who had pathogenic GATA2 mutations and myelodysplasia. Mapping patients' cells onto normal hematopoiesis, we observed deficiency in lymphoid/myeloid progenitors, also evident from highly constrained gene correlations. HSPCs of patients exhibited distinct patterns of gene expression and coexpression compared with counterparts from healthy donors. Distinct lineages showed differently altered transcriptional profiles. Stem cells in patients had dysregulated gene expression related to apoptosis, cell cycle, and quiescence; increased expression of erythroid/megakaryocytic priming genes; and decreased lymphoid priming genes. The prominent deficiency in lympho-myeloid lineages in GATA2 deficiency appeared at least partly due to the expression of aberrant gene programs in stem cells prior to lineage commitment. We computationally imputed cells with chromosomal abnormalities and determined their gene expression; DNA repair genes were downregulated in trisomy 8 cells, potentially rendering these cells vulnerable to second-hit somatic mutations and additional chromosomal abnormalities. Cells with complex cytogenetic abnormalities showed defects in genes related to multilineage differentiation and cell cycle. Single-cell RNA sequencing is powerful in resolving transcriptomes of cell subpopulations despite a paucity of cells in marrow failure. Our study discloses previously uncharacterized transcriptome signatures of stem cells and progenitors in GATA2 deficiency, providing a broad perspective of potential mechanisms by which germline mutations modulate early hematopoiesis in a human disease. This trial was registered at www.clinicaltrials.gov as NCT01905826, NCT01861106, and NCT00001620.

A Panoply of Rheumatological Manifestations in Patients with GATA2 Deficiency.

PURPOSE: To characterize rheumatological manifestations of GATA2 deficiency. METHODS: Single-center, retrospective review of 157 patients with GATA2 deficiency. Disease course, laboratory results, and imaging findings were extracted. In-person rheumatological assessments were performed on selected, available patients. A literature search of four databases was conducted to identify additional cases. RESULTS: Rheumatological findings were identified in 28 patients, out of 157 cases reviewed (17.8%). Twenty-two of those patients (78.6%) reported symptom onset prior to or in conjunction with the molecular diagnosis of GATA2 deficiency. Notable rheumatological manifestations included: piezogenic pedal papules (PPP), joint hyperextensibility, early onset osteoarthritis, ankylosing spondylitis, and seronegative erosive rheumatoid arthritis. In peripheral blood of patients with rheumatological manifestations and GATA2 deficiency, CD4+ CD3+ helper T cells and naïve CD3+ CD4+ CD62L+ CD45RA+ helper T cell subpopulation fractions were significantly lower, while CD8+ cytotoxic T cell fractions were significantly higher, compared to those without rheumatological manifestations and with GATA2 deficiency. No changes in CD19, CD3, or NK populations were observed. CONCLUSION: GATA2 deficiency is associated with a broad spectrum of rheumatological disease manifestations. Low total helper T lymphocyte proportions and low naïve helper T cell proportions are associated with those most at risk of overt rheumatological manifestations. Further, PPP and joint hyperextensibility may explain some of the nonimmunologically-mediated joint problems encountered in patients with GATA2 deficiency. This catalogue suggests that rheumatological manifestations and immune dysregulation are relatively common in GATA2 deficiency.

Mycobacteria-Specific T Cells May Be Expanded From Healthy Donors and Are Near Absent in Primary Immunodeficiency Disorders.

Mycobacterial Infections can be severe in patients with T-cell deficiency or phagocyte disorders, and treatment is frequently complicated by antimicrobial resistance. Restoration of T-cell immunity via stem cell transplantation facilitates control of mycobacterial infections, but presence of active infections during transplantation is associated with a higher risk of mortality. Adoptive T cell immunotherapy has been successful in targeting viruses, but has not been attempted to treat mycobacterial infections. We sought to expand and characterize mycobacterial-specific T-cells derived from healthy donors in order to determine suitability for adoptive immunotherapy. Mycobacteria-specific T-cells (MSTs) were generated from 10 healthy donors using a rapid ex vivo expansion protocol targeting five known mycobacterial target proteins (AG85B, PPE68, ESXA, ESXB, and ADK). MSTs were compared to T-cells expanded from the same donors using lysate from M. tuberculosis or purified protein derivative from M. avium (sensitin). MST expansion from seven patients with primary immunodeficiency disorders (PID) and two patients with IFN-γ autoantibodies and invasive M. avium infections. MSTs expanded from healthy donors recognized a median of 3 of 5 antigens, with production of IFN-γ, TNF, and GM-CSF in CD4+ T cells. Comparison of donors who received BCG vaccine (n = 6) to those who did not (n = 4) showed differential responses to PPE68 (p = 0.028) and ADK (p = 0.015) by IFN-γ ELISpot. MSTs expanded from lysate or sensitin also recognized multiple mycobacterial antigens, with a statistically significant differences noted only in the response to PPE68 (p = 0.016). MSTs expanded from patients with primary immunodeficiency (PID) and invasive mycobacterial infections showed activity against mycobacterial antigens in only two of seven subjects, whereas both patients with IFN-γ autoantibodies recognized mycobacterial antigens. Thus, MSTs can be generated from donors using a rapid expansion protocol regardless of history of BCG immunization. Most tested PID patients had no detectable T-cell immunity to mycobacteria despite history of infection. MSTs may have clinical utility for adoptive immunotherapy in T-cell deficient patients with invasive mycobacterial infections.

MDS-associated mutations in germline GATA2 mutated patients with hematologic manifestations.

Germline mutation in GATA2 can lead to GATA2 deficiency characterized by a complex multi-system disorder that can present with many manifestations including variable cytopenias, bone marrow failure, myelodysplastic syndrome/acute myeloid leukemia (MDS/AML), and severe immunodeficiency. Penetrance and expressivity within families is often variable. There is a spectrum of bone marrow disease in symptomatic cytopenic patients ranging from hypocellular marrows without overt dysplasia to those with definitive MDS, AML, or chronic myelomonocytic leukemia. Relatives of probands with the same mutations may demonstrate minimal disease manifestations and normal marrows. A comprehensive clinical, hematological and genetic assessment of 25 patients with germline GATA2 mutation was performed. MDS-associated mutations were identified in symptomatic GATA2 patients both with overt MDS and in those with hypocellular/aplastic bone marrows without definitive dysplasia. Healthy relatives of probands harboring the same germline GATA2 mutations had essentially normal marrows that were overall devoid of MDS-associated mutations. The findings suggest that abnormal clonal hematopoiesis is a common event in symptomatic germline mutated GATA2 patients with MDS and also in those with hypocellular marrows without overt morphologic evidence of dysplasia, possibly indicating a pre-MDS stage warranting close monitoring for disease progression.