Society of Critical Care Medicine and the Infectious Diseases Society of America Guidelines for Evaluating New Fever in Adult Patients in the ICU.

RATIONALE: Fever is frequently an early indicator of infection and often requires rigorous diagnostic evaluation. OBJECTIVES: This is an update of the 2008 Infectious Diseases Society of America and Society (IDSA) and Society of Critical Care Medicine (SCCM) guideline for the evaluation of new-onset fever in adult ICU patients without severe immunocompromise, now using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. PANEL DESIGN: The SCCM and IDSA convened a taskforce to update the 2008 version of the guideline for the evaluation of new fever in critically ill adult patients, which included expert clinicians as well as methodologists from the Guidelines in Intensive Care, Development and Evaluation Group. The guidelines committee consisted of 12 experts in critical care, infectious diseases, clinical microbiology, organ transplantation, public health, clinical research, and health policy and administration. All task force members followed all conflict-of-interest procedures as documented in the American College of Critical Care Medicine/SCCM Standard Operating Procedures Manual and the IDSA. There was no industry input or funding to produce this guideline. METHODS: We conducted a systematic review for each population, intervention, comparison, and outcomes question to identify the best available evidence, statistically summarized the evidence, and then assessed the quality of evidence using the GRADE approach. We used the evidence-to-decision framework to formulate recommendations as strong or weak or as best-practice statements. RESULTS: The panel issued 12 recommendations and 9 best practice statements. The panel recommended using central temperature monitoring methods, including thermistors for pulmonary artery catheters, bladder catheters, or esophageal balloon thermistors when these devices are in place or accurate temperature measurements are critical for diagnosis and management. For patients without these devices in place, oral or rectal temperatures over other temperature measurement methods that are less reliable such as axillary or tympanic membrane temperatures, noninvasive temporal artery thermometers, or chemical dot thermometers were recommended. Imaging studies including ultrasonography were recommended in addition to microbiological evaluation using rapid diagnostic testing strategies. Biomarkers were recommended to assist in guiding the discontinuation of antimicrobial therapy. All recommendations issued were weak based on the quality of data. CONCLUSIONS: The guidelines panel was able to formulate several recommendations for the evaluation of new fever in a critically ill adult patient, acknowledging that most recommendations were based on weak evidence. This highlights the need for the rapid advancement of research in all aspects of this issue-including better noninvasive methods to measure core body temperature, the use of diagnostic imaging, advances in microbiology including molecular testing, and the use of biomarkers.

Donor source and post-transplantation cyclophosphamide influence outcome in allogeneic stem cell transplantation for GATA2 deficiency.

GATA2 deficiency was described in 2011, and shortly thereafter allogeneic hematopoietic stem cell transplantation (HSCT) was shown to reverse the hematologic disease phenotype. However, there remain major unanswered questions regarding the type of conditioning regimen, type of donors, and graft-versus-host disease (GVHD) prophylaxis. We report 59 patients with GATA2 mutations undergoing HSCT at National Institutes of Health between 2013 and 2020. Primary endpoints were engraftment, reverse of the clinical phenotype, secondary endpoints were overall survival (OS), event-free survival (EFS), and the incidence of acute and chronic GVHD. The OS and EFS at 4 years were 85·1% and 82·1% respectively. Ninety-six percent of surviving patients had reversal of the hematologic disease phenotype by one-year post-transplant. Incidence of grade III-IV aGVHD in matched related donor (MRD) and matched unrelated donor recipients (URD) patients receiving Tacrolimus/Methotrexate for GVHD prophylaxis was 32%. In contrast, in the MRD and URD who received post-transplant cyclophosphamide (PT/Cy), no patient developed grade III-IV aGVHD. Six percent of haploidentical related donor (HRD) recipients developed grade III-IV aGVHD. In summary, a busulfan-based HSCT regimen in GATA2 deficiency reverses the hematologic disease phenotype, and the use of PT/Cy reduced the risk of both aGVHD and cGVHD.

Incidence of Cytomegalovirus disease and viral replication kinetics in seropositive liver transplant recipients managed under preemptive therapy in a tertiary-care center in Mexico City: a retrospective cohort study.

BACKGROUND: In the absence of an adequate prevention strategy, up to 20% of CMV IgG+ liver transplant recipients (LTR) will develop CMV disease. Despite improved reporting in CMV-DNAemia, there is no consensus as to what the ideal CMV-DNAemia cutoff for a successful preemptive strategy is. Each transplant centre establishes their own threshold. We aimed to determine the effectiveness of our preventive strategy in CMV IgG+ LTR, and evaluate CMV replication kinetics. METHODS: In this retrospective study we determined the incidence of CMV disease in the first 6 months following transplantation in CMV seropositive LTR in a tertiary-care centre in Mexico. Secondary outcomes were determining the number of patients who required preemptive therapy (treatment cutoff ≥ 4000 UI/ml), adherence to the centre's prevention protocol and calculation of viral replication kinetics. RESULTS: One-hundred and twenty-four patients met inclusion criteria. Four patients (3.2%) developed CMV disease. Ninety-six (85%) had detectable DNAemia and 25 (22%) asymptomatic patients received preemptive therapy, none of them developed CMV disease. The highest viral loads were observed on the second posttransplant month. The number of viral load measurements decreased over time. Patients with DNAemia ≥ 4000 UI/ml had a faster viral load growth rate, shorter viral load duplication time, and higher basic reproductive number. Viral load growth rate and autoimmune hepatitis were associated with development of DNAemia ≥ 4000 UI/ml. CONCLUSION: Cytomegalovirus disease occurred in 3.2% of the study subjects. Preemptive therapy using a threshold of CMV ≥ 4000 UI/ml was effective in reducing the incidence of end-organ disease. The viral replication parameters described in this population highlight the importance of frequent monitoring, a challenging feat for transplant programs in low- and middle-income countries.

Febrile neutropenia management and outcomes in hematopoietic cell transplantation for chronic granulomatous disease.

OBJECTIVE: We analyzed events and therapies related to febrile neutropenia in patients receiving hematopoietic cell transplantation (HCT) for chronic granulomatous disease (CGD). METHODS: Three protocols for HCT were used to extract the relation between conditioning and infectious complications during transplantation for CGD, especially the relation of fever and neutropenia to microbiological events and antibiotic therapy. RESULTS: Sixty-nine recipients received either reduced intensity conditioning with matched related or unrelated donors or conditioning specific to haploidentical-related donors utilizing posttransplant cyclophosphamide. Fever prior to neutropenia was common (52) and in eight recipients, Gram negative bacterial infection occurred prior to neutropenia, and in nine during neutropenia. Alemtuzumab as conditioning was associated with preneutropenic infection. Empiric therapy (noncarbapenem) by institutional guideline was given in 40. Carbapenems were given before neutropenia (8) or as empiric therapy in neutropenia (18), or a switch to a carbapenem (n = 22) occurred in 48 cases. No deaths related to infection associated with neutropenia occurred. CONCLUSION: The management of febrile neutropenia in HCT for CGD led to no deaths related to infection associated with neutropenia. Bacteremias occurred both prior to neutropenia and during neutropenia. Bacteria isolated may have represented the recrudescence of prior infection, representing the population transplanted and the platform for HCT. The treatment of prior infections may have had an influence on the necessity of carbapenem use as either empiric or directed therapy for bacterial infections.

Genetic, Immunological, and Clinical Features of the First Mexican Cohort of Patients with Chronic Granulomatous Disease.

PURPOSE: Chronic granulomatous disease (CGD) is a primary immunodeficiency characterized by an inability of phagocytes to produce reactive oxygen species, impairing their killing of various bacteria and fungi. We summarize here the 93 cases of CGD diagnosed in Mexico from 2011 to 2019. METHODS: Thirteen Mexican hospitals participated in this study. We describe the genetic, immunological, and clinical features of the 93 CGD patients from 78 unrelated kindreds. RESULTS: Eighty-two of the patients (88%) were male. All patients developed bacterial infections and 30% suffered from some kind of fungal infection. Fifty-four BCG-vaccinated patients (58%) presented infectious complications of BCG vaccine. Tuberculosis occurred in 29%. Granulomas were found in 56% of the patients. Autoimmune and inflammatory diseases were present in 15% of patients. A biological diagnosis of CGD was made in 89/93 patients, on the basis of NBT assay (n = 6), DHR (n = 27), and NBT plus DHR (n = 56). The deficiency was complete in all patients. The median age of biological diagnosis was 17 months (range, 0-186 months). A genetic diagnosis was made in 83/93 patients (when material was available), corresponding to CYBB (n = 64), NCF1 (n = 7), NCF2 (n = 7), and CYBA (n = 5) mutations. CONCLUSIONS: The clinical manifestations in these Mexican CGD patients were similar to those in patients elsewhere. This cohort is the largest in Latin America. Mycobacterial infections are an important cause of morbidity in Mexico, as in other countries in which tuberculosis is endemic and infants are vaccinated with BCG. X-linked CGD accounted for most of the cases in Mexico, as in other Latin American countries. However, a significant number of CYBA and NCF2 mutations were identified, expanding the spectrum of known causal mutations.

TREATMENT STRATEGIES AND OUTCOME OF PARVOVIRUS B19 INFECTION IN KIDNEY TRANSPLANT RECIPIENTS: A CASE SERIES AND LITERATURE REVIEW OF 128 PATIENTS.

BACKGROUND: There is no specific antiviral treatment for parvovirus B19 (PVB19) infection. OBJECTIVE: The objective of this study was to study the treatment and outcome of PVB19 infection in kidney transplant recipients (KTR) at our institution, and cases published in the medical literature. METHODS: We conducted a retrospective review of PVB19 infection in KTR at an academic medical center over a 16-year period and summarized the data on its treatment and outcome in 120 KTR in the medical literature. RESULTS: In our cohort of eight patients, the median time to the onset of PVB19 disease was 7.2 weeks after transplantation. All patients had severe aregenerative anemia (mean hemoglobin (Hb) of 6.2 ± 1.0 g/dl); all were treated with a reduction in their immunosuppressive regimen and the administration of single-dose intravenous immunoglobulin (IVIG) (mean total dosage of 0.87 ± 0.38 g/kg). The median time to anemia improvement (Hb >10 g/dl) was 3-week post-treatment. No recurrences were documented during follow-up (median 25 months). Among 128 patients (including our cohort of 8 and 120 reported in literature), therapeutic strategies included: 43% IVIG alone, 39% IVIG and reduced immunosuppression, 9% reduction of immunosuppression, and 9% conservative therapy. Clinical relapses were observed in 35% of 71 reported cases. CONCLUSIONS: In KTR, decreasing immunosuppression and the administration of low-dose immunoglobulin seem to be not worse than the standard dose in PVB19 infection.

Allogeneic Hematopoietic Stem Cell Transplantation for GATA2 Deficiency Using a Busulfan-Based Regimen.

Allogeneic hematopoietic stem cell transplantation (HSCT) reverses the bone marrow failure syndrome due to GATA2 deficiency. The intensity of conditioning required to achieve reliable engraftment and prevent relapse remains unclear. Here, we describe the results of a prospective study of HSCT in 22 patients with GATA2 deficiency using a busulfan-based conditioning regimen. The study included 2 matched related donor (MRD) recipients, 13 matched unrelated donor (URD) recipients, and 7 haploidentical related donor (HRD) recipients. MRD and URD recipients received 4 days of busulfan and 4 days of fludarabine. HRD recipients received low-dose cyclophosphamide for 2 days, fludarabine for 5 days, 2 to 3 days of busulfan depending on cytogenetics, and 200 cGy total body irradiation. MRD and URD recipients received tacrolimus and short-course methotrexate for graft-versus-host disease (GVHD) prophylaxis. HRD recipients received high-dose post-transplant cyclophosphamide (PTCy) followed by tacrolimus and mycophenolate mofetil. At a median follow-up of 24 months (range, 9 to 50), 19 of 22 patients were alive with reversal of the disease phenotype and correction of the myelodysplastic syndrome, including eradication of cytogenetic abnormalities. Three patients died: 1 from refractory acute myelogenous leukemia, 1 from GVHD, and 1 from sepsis. There was a 26% incidence of grades III to IV acute GVHD in the MRD and URD groups and no grades III to IV acute GVHD in the HRD cohort. Similarly, there was a 46% incidence of chronic GVHD in the MRD and URD cohorts, whereas only 28% of HRD recipients developed chronic GVHD. Despite excellent overall disease-free survival (86%), GVHD remains a limitation using standard prophylaxis for GVHD. We are currently extending the use of PTCy to the MRD and URD cohorts to reduce GVHD.

Aspergillus infection of the larynx in a solid organ transplant recipient.

Primary laryngeal aspergillosis is a rare condition. Only a few cases have been reported in the past years. Most of them have been reported in healthy patients or with a mild immunocompromised state. We report a case of primary laryngeal aspergillosis in a solid organ transplant recipient (SOT), an infection not previously described in this population; we reviewed the published literature in all populations.

Resolution of Multifocal Epstein-Barr Virus-Related Smooth Muscle Tumor in a Patient with GATA2 Deficiency Following Hematopoietic Stem Cell Transplantation.

We performed allogeneic hematopoietic stem cell transplantation in a patient with GATA2 deficiency and an Epstein-Barr virus (EBV)-related spindle cell tumor involving the liver and possibly bone. He received a matched-related donor transplant with donor peripheral blood stem cells following a myeloablative conditioning regimen. He achieved rapid and high levels of donor engraftment and had complete reversal of the clinical and immunologic phenotype of MonoMAC/GATA2 deficiency and eradication of the EBV tumors after 3 years of follow-up. Thus, allogeneic hematopoietic stem cell transplant results in reconstitution of immunologic function and cure of EBV-associated malignancy in MonoMAC/GATA2 deficiency.

GATA2 deficiency-associated bone marrow disorder differs from idiopathic aplastic anemia.

Germ-line GATA2 gene mutations, leading to haploinsufficiency, have been identified in patients with familial myelodysplastic syndrome/acute myeloid leukemia, monocytopenia and mycobacterial infections, Emberger syndrome, and dendritic cell, monocyte, B-, and NK-cell deficiency. GATA2 mutations have also been reported in a minority of patients with congenital neutropenia and aplastic anemia (AA). The bone marrow (BM) from patients with GATA2 deficiency is typically hypocellular, with varying degrees of dysplasia. Distinguishing GATA2 patients from those with AA is critical for selecting appropriate therapy. We compared the BM flow cytometric, morphologic, and cytogenetic features of 28 GATA2 patients with those of 32 patients being evaluated for idiopathic AA. The marrow of GATA2 patients had severely reduced monocytes, B cells, and NK cells; absent hematogones; and inverted CD4:CD8 ratios. Atypical megakaryocytes and abnormal cytogenetics were more common in GATA2 marrows. CD34(+) cells were comparably reduced in GATA2 and AA. Using these criteria, we prospectively identified 4 of 32 patients with suspected AA who had features suspicious for GATA2 mutations, later confirmed by DNA sequencing. Our results show that routine BM flow cytometry, morphology, and cytogenetics in patients who present with cytopenia(s) can identify patients for whom GATA2 sequencing is indicated.

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.

Matched related and unrelated donor hematopoietic stem cell transplantation for DOCK8 deficiency.

We performed allogeneic hematopoietic stem cell transplantation in 6 patients with mutations in the dedicator-of-cytokinesis-8 (DOCK8) gene using a myeloablative conditioning regimen consisting of busulfan 3.2 mg/kg/day i.v. for 4 days and fludarabine 40 mg/m(2)/day for 4 days. Three patients received allografts from matched related donors and 3 patients from matched unrelated donors. Two patients received peripheral blood stem cells and 4 patients bone marrow hematopoietic stem cells. Tacrolimus and short-course methotrexate on days 1, 3, 6, and 11 were used for graft-versus-host-disease (GVHD) prophylaxis. All 6 patients are alive at a median follow-up of 22.5 months (range, 14 to 35). All patients achieved rapid and high levels of donor engraftment and complete reversal of the clinical and immunologic phenotype. Adverse events consisted of acute skin GVHD in 2 patients and post-transplant pulmonary infiltrates in a patient with extensive bronchiectasis pretransplant. Thus, a uniform myeloablative conditioning regimen followed by allogeneic hematopoietic stem cell transplantation in DOCK8 deficiency results in reconstitution of immunologic function and reversal of the clinical phenotype with a low incidence of regimen-related toxicity.

GATA2 haploinsufficiency caused by mutations in a conserved intronic element leads to MonoMAC syndrome.

Previous reports of GATA2 mutations have focused on the coding region of the gene or full gene deletions. We recently identified 2 patients with novel insertion/deletion mutations predicted to result in mRNA nonsense-mediated decay, suggesting haploinsufficiency as the mechanism of GATA2 deficient disease. We therefore screened patients without identified exonic lesions for mutations within conserved noncoding and intronic regions. We discovered 1 patient with an intronic deletion mutation, 4 patients with point mutations within a conserved intronic element, and 3 patients with reduced or absent transcription from 1 allele. All mutations affected GATA2 transcription. Full-length cDNA analysis provided evidence for decreased expression of the mutant alleles. The intronic deletion and point mutations considerably reduced the enhancer activity of the intron 5 enhancer. Analysis of 512 immune system genes revealed similar expression profiles in all clinically affected patients and reduced GATA2 transcript levels. These mutations strongly support the haploinsufficient nature of GATA2 deficiency and identify transcriptional mechanisms and targets that lead to MonoMAC syndrome.

Surveillance of Oseltamivir-Resistant Influenza A(H1N1)pdm09 in Guanajuato State, Mexico from 2009 to 2012.

BACKGROUND: The influenza A(H1N1)pdm09 virus was first identified in Mexico in April 2009, subsequently spreading worldwide. Soon after the WHO declared a pandemic, a series of cases involving oseltamivir-resistant viruses were described, following concerns about the spread of strains resistant to neuraminidase inhibitors that could hamper control measures. To study the prevalence of oseltamivir-resistant influenza A(H1N1)pdm09, we implemented a surveillance program across the state of Guanajuato, Mexico. METHODS: We collected respiratory samples from patients with confirmed infection with influenza A(H1N1)pdm09 virus between 2009 and 2012 in rural and urban regions in Guanajuato, Mexico. Specimens were screened for the H275Y mutation by Sanger sequencing. RESULTS: A total of 1,192 laboratory confirmed influenza A(H1N1)pdm09-positive samples were processed between 2009 and 2012. Using two endpoint real-time polymerase chain reaction, 575 samples were sequenced. Two different clusters, I and II, were identified. The H275Y substitution was found in only one sample from cluster I. CONCLUSIONS: The prevalence of oseltamivir-resistant influenza A(H1N1)pdm09 2009 viruses during the pandemic period and following years was very low in our State.

Nonmyeloablative allogeneic hematopoietic stem cell transplantation for GATA2 deficiency.

We treated 14 patients with GATA2 deficiency using a nonmyeloablative allogeneic hematopoietic stem cell transplantation regimen. Four patients received peripheral blood stem cells from matched related donors (MRD), 4 patients received peripheral blood stem cells from matched unrelated donors (URD), 4 patients received hematopoietic stem cells from umbilical cord blood donors (UCB), and 2 patients received bone marrow cells from haploidentical related donors. MRD and URD recipients received conditioning with 3 days of fludarabine and 200 cGy total body irradiation (TBI). Haploidentical related donor recipients and UCB recipients received cyclophosphamide and 2 additional days of fludarabine along with 200 cGY TBI. MRD, URD, and UCB recipients received tacrolimus and sirolimus for post-transplantation immunosuppression, whereas haploidentical recipients received high-dose cyclophosphamide followed by tacrolimus and mycophenolate mofetil. Eight patients are alive with reconstitution of the severely deficient monocyte, B cell, and natural killer cell populations and reversal of the clinical phenotype at a median follow-up of 3.5 years. Two patients (1 URD recipient and 1 UCB recipient) rejected the donor graft and 1 MRD recipient relapsed with myelodysplastic syndrome after transplantation. We are currently using a high-dose conditioning regimen with busulfan and fludarabine in patients with GATA2 deficiency to achieve more consistent engraftment and eradication of the malignant myeloid clones.

Recombinant human factor VIIa for alveolar hemorrhage following allogeneic stem cell transplantation.

The mortality rate of alveolar hemorrhage (AH) after allogeneic hematopoietic stem cell transplantation is greater than 60% with supportive care and high-dose steroid therapy. We performed a retrospective cohort analysis to assess the benefits and risks of recombinant human factor VIIa (rFVIIa) as a therapeutic adjunct for AH. Between 2005 and 2012, 57 episodes of AH occurred in 37 patients. Fourteen episodes (in 14 patients) were treated with steroids alone, and 43 episodes (in 23 patients) were treated with steroids and rFVIIa. The median steroid dose was 1.9 mg/kg/d (interquartile range [IQR], 0.8 to 3.5 mg/kg/d; methylprednisolone equivalents) and did not differ statistically between the 2 groups. The median rFVIIa dose was 41 µg/kg (IQR, 39 to 62 µg/kg), and a median of 3 doses (IQR, 2 to 17) was administered per episode. Concurrent infection was diagnosed in 65% of the episodes. Patients had moderately severe hypoxia (median PaO2/FiO2, 193 [IQR, 141 to 262]); 72% required mechanical ventilation, and 42% survived to extubation. The addition of rFVIIa did not alter time to resolution of AH (P = .50), duration of mechanical ventilation (P = .89), duration of oxygen supplementation (P = .55), or hospital mortality (P = .27). Four possible thrombotic events (9% of 43 episodes) occurred with rFVIIa. rFVIIa in combination with corticosteroids did not confer clear clinical advantages compared with corticosteroids alone. In patients with AH following hematopoietic stem cell transplantation, clinical factors (ie, worsening infection, multiple organ failure, or recrudescence of primary disease) may be more important than the benefit of enhanced hemostasis from rFVIIa.

Loss-of-function germline GATA2 mutations in patients with MDS/AML or MonoMAC syndrome and primary lymphedema reveal a key role for GATA2 in the lymphatic vasculature.

Recent work has established that heterozygous germline GATA2 mutations predispose carriers to familial myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML), "MonoMAC" syndrome, and DCML deficiency. Here, we describe a previously unreported MDS family carrying a missense GATA2 mutation (p.Thr354Met), one patient with MDS/AML carrying a frameshift GATA2 mutation (p.Leu332Thrfs*53), another with MDS harboring a GATA2 splice site mutation, and 3 patients exhibiting MDS or MDS/AML who have large deletions encompassing the GATA2 locus. Intriguingly, 2 MDS/AML or "MonoMAC" syndrome patients with GATA2 deletions and one with a frameshift mutation also have primary lymphedema. Primary lymphedema occurs as a result of aberrations in the development and/or function of lymphatic vessels, spurring us to investigate whether GATA2 plays a role in the lymphatic vasculature. We demonstrate here that GATA2 protein is present at high levels in lymphatic vessel valves and that GATA2 controls the expression of genes important for programming lymphatic valve development. Our data expand the phenotypes associated with germline GATA2 mutations to include predisposition to primary lymphedema and suggest that complete haploinsufficiency or loss of function of GATA2, rather than missense mutations, is the key predisposing factor for lymphedema onset. Moreover, we reveal a crucial role for GATA2 in lymphatic vascular development.

Acquired ASXL1 mutations are common in patients with inherited GATA2 mutations and correlate with myeloid transformation.

Inherited or sporadic heterozygous mutations in the transcription factor GATA2 lead to a clinical syndrome characterized by non-tuberculous mycobacterial and other opportunistic infections, a severe deficiency in monocytes, B cells and natural killer cells, and progression from a hypocellular myelodysplastic syndrome to myeloid leukemias. To identify acquired somatic mutations associated with myeloid transformation in patients with GATA2 mutations, we sequenced the region of the ASXL1 gene previously associated with transformation from myelodysplasia to myeloid leukemia. Somatic, heterozygous ASXL1 mutations were identified in 14/48 (29%) of patients with GATA2 deficiency, including four out of five patients who developed a proliferative chronic myelomonocytic leukemia. Although patients with GATA2 mutations had a similarly high incidence of myeloid transformation when compared to previously described patients with ASXL1 mutations, GATA2 deficiency patients with acquired ASXL1 mutation were considerably younger, almost exclusively female, and had a high incidence of transformation to a proliferative chronic myelomonocytic leukemia. These patients may benefit from allogeneic hematopoietic stem cell transplantation before the development of acute myeloid leukemia or chronic myelomonocytic leukemia. (ClinicalTrials.gov identifier NCT00018044, NCT00404560, NCT00001467, NCT00923364.).