A spontaneous reversion that restores Wiskott-Aldrich syndrome protein (WASP) expression was reported recently. However, the genetic mechanism underlying the reversion event was unclear. In the present study, a WAS patient with a nonsense mutation (155 C>T, R41X) was followed during a three-year period. No expression of WASP was detected in peripheral blood mononucleated cells (PBMCs) in 2009 and a small population of intracellular WASP positive lymphocytes was detected during the following three years. The increasing trend of the revertant genotype was significant. WASP-expressing cells were present mainly CD56+ NK cells and CD8+ T cells. Sorted WASP+ cells were analyzed, indicating that the population of CD3+ T cells increased from 36.81% to 99.8%. Although the revertant cells in vivo may have a growth advantage, the patient presented a persistent autoimmune disease, thrombocytopenia, and died from extensive pulmonary fibrosis. The results suggest that the clinical consequences of T-cell mosaicism in WAS remain difficult to predict and is not sufficient to fully normalize immune functions in patients with WAS.
Keywords: Flow cytometry; Mutation; Reversion; Wiskott–Aldrich syndrome.
Copyright © 2015 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.