Successful Haploidentical Hematopoietic Stem Cell Transplant for GATA2 Deficiency

Background: GATA2 deficiency results in a clinical syndrome known variably as: MonoMAC for the lack of monocytes and atypical mycobacterial infections (MAC); 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). Reconstitution of the deficient cell compartments in GATA2 deficiency with allogeneic hematopoietic stem cell transplant (HSCT) results in reversal of the infection susceptibility and represents the only curative therapy for both the myeloid disease and the virally driven malignancies seen in this disorder. However, only about one-half of patients that require HSCT will have an HLA-matched related or unrelated donor. Moreover, the use of umbilical cord blood has been reported to be suboptimal in this cohort of patients in whom infection susceptibility underlies much of the need for a transplant.

Methods: We performed haploidentical, related donor HSCT with high dose post-transplant cyclophosphamide (PT/CY) in 3 patients with GATA2 deficiency in whom a suitable HLA matched donor was not available. All three patients had a first degree relative (sibling) who shared at least 1 HLA-haplotype. The first patient, a 21 year-old Chinese woman presented with Hydroa Vacciniforme like T-cell lymphoma involving her lung, bowel (resulting in multiple small bowel resections and ileostomy), and skin (with large ulcerative lesions); multiple thrombotic cerebral events; and macrophage activation syndrome requiring etoposide and high dose prednisone in the intensive care unit (ICU). The second patient, a 20 year-old Hispanic female, presented with myelodysplasia (MDS), profound neutropenia, an invasive fungal sinusits due to Fusarium sp., and recurrent bacteremias. The third patient, a 45 year-old woman, presented with Emberger’s Syndrome, multiple episodes of bacterial and fungal sepsis and hypocellular MDS. All three patients received cyclophosphamide 14.5mg/kg on day’s -6 and-5; fludarabine 30mg/m² on day’s -6 through -2; 200cGy of total body irradiation (TBI) on day -1. Patients 2 and 3 also received busulfan 3.2 mg/kg on day’s -4 and -3 because of MDS. All 3 patients received high dose PT/CY 50mg/kg on day’s +3 and +4, and mycophenolate mofetil and tacrolimus starting on day +5.

Results: All 3 patients engrafted at a mean of 18 days and all are alive at a median follow-up of 9 months (range, 5 to 13 months). All three patients achieved 100% donor myeloid and lymphoid chimerim by day +100 post-transplant. The first patient had complete resolution of her T-cell lymphoma and macrophage activation syndrome, the second patient has had complete reversal of her hematopoietic and infectious phenotype, and the third patient has had resolution of her infectious complications that required continuous IV Daptomycin for 5 years prior to transplant. In addition, all three patients had complete reconstitution of the monocyte, NK cell, and B-lymphocyte compartments that were severely deficient prior to transplant. The main toxicity was mucositis, which required intravenous narcotics in all three patients. Lastly, the first patient developed late grade I liver graft-versus-host disease (GVHD) that was responsive to cyclosporine, the second patient developed grade I acute GVHD of skin that was responsive to topical steroids, and the third patient had no evidence of acute or chronic GVHD.

Conclusions: Haploidentical, related donor HSCT represents a safe and effective viable alternative for patients with GATA2 deficiency who lack an HLA-matched donor, including patients such as our first patient who was in the ICU at the time of transplant.