TELOMERE BIOLOGY DISORDERS: PHENOTYPE AND GENETIC FINDINGS

UCB. Graft source was bone marrow (n=26), peripheral blood (n=6) and cord blood (n=3).Myeloablative conditioning consisting of Cyclophosphamide/ATG was used in all MSD/autologous recipients, MUD recipients received Cyclophosphamide/Fludarabine/ATG with five also receiving TBI .Fourteen patients underwent upfront HSCT, while twenty had received prior immunosuppressive therapy (IST).Results: Engraftment was achieved in 30/34 (86%) patients.Median neutrophil and platelet engraftment times was 20 and 23 days respectively.Four patients experienced Primary Graft Failure, with 2 achieving engraftment after a second and third transplant respectively.aGvHD occurred in 8/34 patients (23.5%) (6 with Grade II-III, 2 with Grade IV).Immune reconstitution was observed in all 25 evaluable patients by 12 months.Median follow-up was 76.6 months.25/34 patients are alive with normal blood counts.Estimated 5-year Overall Survival was 76% in the entire cohort; 93% in the MSD group (95% CI, 61%-99%) (p = 0.02).TRM at 30 days and 12 months was 6% (95% CI, 1.5%-21.5%)and 21% (95% CI, 10%-38%) respectively.Cause of death was infection (6/9), refractory GvHD (2/9) and cardiac complications (1/9).In univariate analysis Donor type and the presence of aGvHD were the strongest predictors impacting OS.Prior IST did not impact outcome.Conclusions: HSCT for SAA showed excellent outcomes in MSD recipients.Donor type and aGvHD were key survival predictors.Notably, prior IST had no significant impact on outcomes, suggesting upfront HSCT may offer an advantage by avoiding associated burdens and delays.The favorable outcomes observed with haploidentical HSCT using TCR+/CD19+ depletion show promise in expanding donor options.