Acquired Omenn-Like Syndrome, a Novel Posttransplant Autoaggression Syndrome Reversed by Rapamycin

Graft-versus-host disease is uncommon in autologous hematopoietic cell transplantation (HCT) and is typically brief and mild. We report unusual, protracted, and severe Omenn syndrome-like autoaggression following autologous HCT. We identified a profound FOXP3(+) regulatory T cell defect that coincided with hyperinflammatory T cell responses which were reversible with rapamycin in vitro.