INTRODUCTION
Autoimmune cytopenias are a rare but potentially life-threatening
complication after hematopoietic stem cell transplant (HSCT). Autoimmune
hemolytic anemia (AIHA) is the most common type of post-HSCT immune
cytopenia and occurs when antibodies are directed against donor red
blood cell antigens. The incidence of AIHA in the pediatric transplant
population has been reported between 2.4-6%.[1-3] Given the rarity
of post-transplant AIHA, guidelines for monitoring, management, and
expected outcomes are not available.
Previously reported risk factors for the development of AIHA include
unrelated donor use, conditioning regimens without total body
irradiation, peripheral blood and cord blood transplants, non-malignant
indication for transplant, and chronic graft-versus-host disease
(GVHD).[4-7] Limited evidence suggests that variables within the
immunologic landscape, including pre-determined factors such as pre-HSCT
serotherapy and T cell depletion as well as post-HSCT factors such as B
and T cell recovery, T cell mixed chimerism, and infectious
complications, may contribute to the risk of AIHA.[3, 5, 8] The
complexity and lack of comprehensive understanding of the
pathophysiology of AIHA after HSCT makes treatment challenging, and
there are low reported response rates to first line therapy with
corticosteroids.[2, 9-11]
We performed a retrospective cohort analysis describing the incidence of
post-transplant AIHA in pediatric patients undergoing HSCT at a tertiary
care academic institution, characterizing current management strategies,
and describing patient outcomes. We also performed a matched
case-control analysis to compare outcomes of patients with AIHA to those
without AIHA.