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Background: Mutations in the zinc finger transcription factor GATA2 are responsible for: MonoMAC, monocytopenia with nontuberculous mycobacterial (NTM) infections; DCML, dendritic cell, monocyte and lymphoid cell deficiency; Emberger's syndrome with lymphedema and monosomy 7; and familial myelodysplastic syndrome (MDS)/acute myelogenous leukemia (AML). Allogeneic hematopoietic stem cell transplant (HSCT) represents the only definitive therapy for GATA2 deficiency. Methods: Eleven patients with GATA2 deficiency received a myeloablative-conditioning regimen (2 matched related donors or MRD, 4 matched unrelated donors or URD, and 5 haploidentical related donors. MRD and URD received busulfan 3.2 mg/kg/day and fludarabine 40 mg/m2/day on days -6, -5, -4, and -3. Haploidentical related donors received cyclophosphamide 14.5 mg/kg on day's -6 and -5, fludarabine 30 mg/m2/day on day's -6 to -2, busulfan 3.2 mg/kg/day on day's -4 and -3, and 200 cGy TBI on day -1. MRD and URD recipients received tacrolimus and short course methotrexate post-transplant, while haploidentical related donor recipients received cyclophosphamide 50 mg/kg/day on days + 3 and +4 followed by tacrolimus and mycophenolate mofetil as post-transplant immunosuppression for graft-versus-host disease. Results: Ten of the 11 (91%) of patients are alive and disease-free at a mean follow-up of 12 months (range 1 mo to 24 mo). One URD recipient died from persistent acute myelogenous leukemia. Four patients developed graft-versus-host disease, one case Grade 4. All 10 patients who survived had complete reconstitution of the monocyte, NK, and B-lymphocyte compartments, the three cell compartments that were severely deficient pre-transplant. All 10 patients had reversal of the infection susceptibility phenotype. In particular, there were no recurrences of NTM infections. Importantly, all 10 patients had correction of the cytogenetic abnormalities present pre-transplant (5 patients with trisomy 8 and 1 patient with monosomy 7). Conclusions: Myeloablative HSCT in GATA2 deficiency results in uniform engraftment and reversal of the hematologic, cytogenetic, and clinical manifestations of GATA2 deficiency. There was a low regimen-related toxicity, even in this cohort of patients with considerable co-morbidities. We anticipate that with HSCT earlier in the clinical course, before significant organ damage or clonal evolution of MDS to AML or CMML occurs, the outcome of allogeneic HSCT in patients with GATA2 deficiency will continue to improve. Haploidentical related donor transplant appears to be particularly well suited for this disease, especially when the disease presents as a hypocellular myelodysplastic syndrome. Disclosures No relevant conflicts of interest to declare.

Background Heterozygous sporadic or inherited mutations in the GATA2 gene result in a syndrome known variably as: “MonoMAC” for monocytopenia with nontuberculous mycobacterial (NTM) infections; DCML, dendritic cell, monocyte and lymphoid cell deficiency; Emberger's syndrome, lymphedema and MDS with monosomy 7; and familial myelodysplastic syndrome (MDS)/acute myelogenous leukemia (AML). Life-threatening opportunistic infections and myeloid transformation constitute the rationale for allogeneic hematopoietic stem cell transplant (HSCT) for GATA2 deficiency. Methods We treated 14 patients with GATA2 deficiency using a nonmyeloablative-conditioning regimen and matched related donors (MRD) (n=4), matched unrelated donors (URD) (n=4), umbilical cord blood (UCB) (n=4), and haploidentical related donor (HD) (n=2) sources. There was considerable pre-transplant morbidity in this cohort of patients. MRD and URD recipients received 200 cGy of total body irradiation (TBI) and 3 days of fludarabine; UCB recipients received 200cGy TBI, cyclophosphamide 50 mg/kg on day -6, and 5 days of fludarabine; HD recipients received 200cGy TBI, cyclophosphamide 14.5 mg/kg on days -6 and -5, and fludarabine for 5 days. MRD, URD, and UCB recipients received tacrolimus and sirolimus for GVHD prophylaxis. HD recipients received cyclophosphamide 50 mg/kg on days + 3 and +4 followed by tacrolimus and mycophenolate mofetil. MRD and URD donor recipients received peripheral blood stem cells (PBSC) and HD donor recipients received bone marrow stem cells. Results (table 1): The median follow-up in the MRD cohort was 32 months, excluding one early death in a patient on a ventilator at the time of transplant. One patient relapsed one year post-transplant and required re-transplant using a myeloablative regimen. All 4 patients in this cohort developed acute GVHD. In the URD cohort, all patients are alive, however one patient rejected the PBSC graft and required a second URD transplant from a different donor. Two patients developed acute GVHD. In the UCB cohort, there was one early death from sepsis, one graft rejection, and one donor cell leukemia that occurred 2.5 years post-transplant. The remaining patient had a complicated course, but at 3 years post-transplant he is fully engrafted, on no medications, and has no GVHD. In the two patients who received HD transplants, one had progressed to proliferative CMML prior to transplant and died in the immediate post-transplant period. The second patient engrafted and is doing well two months post-transplant with resolution of an EBV-driven T cell lymphoma. All patients who engrafted had complete reconstitution of the monocyte, NK, and B lymphocyte compartments; all had correction of the underlying myeloid malignancy, and reversal of the infection susceptibility phenotype, characteristic of the disease. In particular, there were no recurrences of NTM. Conclusions Nonmyeloablative HSCT in GATA2 deficiency results in reconstitution of the severely deficient monocyte, B and NK cell populations and correction of the infection susceptibility phenotype. However, 1 of 4 MRD recipients developed a relapse of the original clone, and 1 of 4 URD recipients rejected the donor PBSC. The incidence of relapse and rejection, as well as the unfavorable cytogenetics in many patients, suggests that a more intense conditioning regimen is required to treat these patients. In this regard, we are now using a myeloablative regimen with busulfan and fludarabine. The poor outcome with UCB in this cohort of immunocompromised patients supports the use of HD transplants when a MRD or URD is not available. We anticipate that with increasing use of genetic testing for GATA2 mutations, patients will be transplanted earlier in the course of disease, before significant organ damage or clonal evolution of MDS to AML and CMML occurs, and that the outcome of allogeneic HSCT in these patients will continue to improve with these modifications in the transplant approach. Disclosures: No relevant conflicts of interest to declare.

Abstract 3091 Background: Recently, sporadic and heritable mutations in the zinc finger transcription factor GATA2 were shown to be responsible for four different syndromes in young adults coupling opportunistic infection with a predilection to develop myelodysplastic syndrome (MDS)/acute myelogenous leukemia (AML). These four syndromes are: MonoMAC, monocytopenia with nontuberculous mycobacterial (NTM) infections; DCML, dendritic cell, monocyte and lymphoid cell deficiency; Emberger's syndrome, lymphedema and MDS with monosomy 7; and familial MDS/AML. Life-threatening infections, and the transformation to AML, either alone or together, constitute a rationale for allogeneic hematopoietic stem cell transplant (HSCT) for GATA2 deficiency. Methods: We evaluated matched related, unrelated, and umbilical cord blood as donor sources for nonmyeloablative conditioning for HSCT in GATA2 deficiency. Twelve patients with GATA2 deficiency underwent allogeneic transplant: 4 received peripheral blood stem cells (PBSCs) from matched related-donors (MRD), 4 received PBSC from matched unrelated-donors (MUD), and 4 received umbilical cord blood (UCB) units. Recipients of MRD and MUD transplant received fludarabine and 200cGy of total body irradiation (TBI), while UCB recipients received cyclophosphamide 50 mg/kg, fludarabine, and 200cGy of TBI. All patients received tacrolimus and sirolimus for GVHD prophylaxis. This cohort of patients had considerable pre-transplant morbidity: two patients required baseline oxygen for pulmonary alveolar proteinosis, one of whom was on a ventilator at the time of transplant; one patient had active hepatitis C that was not responding to therapy; one patient had RAEB-2; two patients were platelet transfusion-dependent; one patient had recurrent strokes and culture negative endocarditis two months before transplant. Results: Median follow-up for patients was 14.4 months (range 0.2–38.2 months). Ten of 11 patients engrafted at a median of 10 days (range 0–76); engraftment was not evaluable in a recipient of an UCB transplant due to death early in the post-transplant period. One rejection occurred in a recipient of a double UCB transplant who had been heavily transfused pre-transplant. All patients who engrafted had complete reconstitution of the monocyte, NK, and B-lymphocyte compartments, the three cell compartments that were severely deficient pre-transplant, and all had reversal of the infection susceptibility phenotype, characteristic of the disease. In particular, there were no recurrences of NTM infection and extensive human papilloma virus infections regressed starting around 6 months post transplant. Two patients required a single cycle of pre-transplant chemotherapy for RAEB-1 and RAEB-2, respectively. In both patients the monosomy 6 and monosomy 7 clones have not recurred, now 2.5 years and 9 months following single UCB and MUD transplant, respectively. Three patients died, two early after transplant. One recipient of UCB, who had pre-transplant hepatitis C, died on day+7 of fulminant liver failure and sepsis. A second patient, who was intubated at the time of transplant because of severe pulmonary alveolar proteinosis and pulmonary hypertension, died on day + 88 of grade IV GVHD after MRD transplant. The third patient died 9 months after transplant of sepsis. One recipient of a MRD relapsed from her MDS at 1 year following transplant and was retransplanted using a myeloablative conditioning regimen. She is alive with no evidence of MDS at 3 months. Acute GVHD developed in 6 patients, five of which were steroid-responsive. One patient developed chronic GVHD. Other complications included immune mediated cytopenias that responded to rituximab and eltrombopag. Conclusions: Nonmyeloablative HSCT in GATA2 deficiency results in reconstitution of the severely deficient monocyte, B and NK cell populations and reversal of the infection susceptibility phenotype. The TRM in this cohort of patients with severe comorbidities was 25%. Now that genetic testing for GATA2 mutations is available, we anticipate that earlier diagnosis will enable patients to be transplanted earlier in the course of disease, before significant organ damage or clonal evolution of MDS to AML. Disclosures: No relevant conflicts of interest to declare.