Hematopoietic Cell Transplantation with Cryopreserved Grafts for Severe Aplastic Anemia

With the COVID-19 pandemic and the ensuing barriers to the collection and transport of donor cells, it is often necessary to collect and cryopreserve grafts before initiation of transplantation conditioning. The effect on transplantation outcomes in nonmalignant disease is unknown. This analysis examined the effect of cryopreservation of related and unrelated donor grafts for transplantation for severe aplastic anemia in the United States during 2013 to 2019. Included are 52 recipients of cryopreserved grafts who were matched for age, donor type, and graft type to 194 recipients who received noncryopreserved grafts. Marginal Cox regression models were built to study the effect of cryopreservation and other risk factors associated with outcomes. We recorded higher 1-year rates of graft failure (hazard ratio [HR], 2.26; 95% confidence interval, 1.17 to 4.35; P = .01) and of 1-year overall mortality (HR, 3.13; 95% CI, 1.60 to 6.11; P = .0008) after transplantation of cryopreserved compared with noncryopreserved grafts, with adjustment for sex, performance score, comorbidity, cytomegalovirus serostatus, and ABO blood group match. The incidence of acute and chronic graft-versus-host disease did not differ between the 2 groups. Adjusted probabilities of 1-year survival were 73% (95% CI, 60% to 84%) in the cryopreserved graft group and 91% (95% CI, 86% to 94%) in the noncryopreserved graft group. These data support the use of noncryopreserved grafts whenever possible in patients with severe aplastic anemia.