Long-term outcomes and GVHD in allogeneic hematopoietic cell transplantation abroad: a 14-year UAE multi-center...

Hematopoietic cell transplant (HCT) data are well reported, but for cohorts transplanted abroad and returning to countries without transplant services, long-term outcomes such as chronic graft versus host disease (GVHD) and overall survival remain poorly captured, underscoring the need for longitudinal follow-up.

We conducted a 14-year retrospective multi-center study of allogeneic HCT recipients followed at three tertiary hospitals in the United Arab Emirates(UAE). Transplant characteristics, conditioning, GVHD prophylaxis, and outcomes were abstracted from medical records. Crude survival was reported for all indications, Kaplan-Meier (KM) overall survival for diseases with ≥20 cases.

A total of 363 allogeneic HCTs were analyzed. Overall, cohort characteristics differed from those reported in the literature: adults undergoing HCT were relatively young, female predominance was observed in pediatric malignancies and immune deficiencies, and matched unrelated donor (MUD) utilization was limited, while peripheral blood stem cell use was higher than typically described. In contrast, haploidentical donor utilization, conditioning intensity, and GVHD prophylaxis patterns were broadly consistent with international practice. GVHD incidence was high:69.2% in adults; 45.7% in children. In adults with acute myeloid leukemia (AML), acute GVHD was associated with an inferior 5-year OS (p = 0.036). In pediatric AML, both acute-/chronic GVHD were linked to poor survival (<50%), while survival for acute lymphoblastic leukemia (B-/T-ALL) exceeded 85%. cGVHD worsened overall survival (OS) more in pediatrics than adults.

Although most findings aligned with established benchmarks, the high GVHD incidence and its association with adverse outcomes highlight the need for improved prevention strategies and the development of local transplant services.