B-cell reconstitution after lentiviral vector-mediated gene therapy in patients with Wiskott-Aldrich syndrome

J Allergy Clin Immunol. 2015 Sep;136(3):692-702.e2. doi: 10.1016/j.jaci.2015.01.035. Epub 2015 Mar 16.

Abstract

Background: Wiskott-Aldrich syndrome (WAS) is a severe X-linked immunodeficiency characterized by microthrombocytopenia, eczema, recurrent infections, and susceptibility to autoimmunity and lymphomas. Hematopoietic stem cell transplantation is the treatment of choice; however, administration of WAS gene-corrected autologous hematopoietic stem cells has been demonstrated as a feasible alternative therapeutic approach.

Objective: Because B-cell homeostasis is perturbed in patients with WAS and restoration of immune competence is one of the main therapeutic goals, we have evaluated reconstitution of the B-cell compartment in 4 patients who received autologous hematopoietic stem cells transduced with lentiviral vector after a reduced-intensity conditioning regimen combined with anti-CD20 administration.

Methods: We evaluated B-cell counts, B-cell subset distribution, B cell-activating factor and immunoglobulin levels, and autoantibody production before and after gene therapy (GT). WAS gene transfer in B cells was assessed by measuring vector copy numbers and expression of Wiskott-Aldrich syndrome protein.

Results: After lentiviral vector-mediated GT, the number of transduced B cells progressively increased in the peripheral blood of all patients. Lentiviral vector-transduced progenitor cells were able to repopulate the B-cell compartment with a normal distribution of B-cell subsets both in bone marrow and the periphery, showing a WAS protein expression profile similar to that of healthy donors. In addition, after GT, we observed a normalized frequency of autoimmune-associated CD19(+)CD21(-)CD35(-) and CD21(low) B cells and a reduction in B cell-activating factor levels. Immunoglobulin serum levels and autoantibody production improved in all treated patients.

Conclusions: We provide evidence that lentiviral vector-mediated GT induces transgene expression in the B-cell compartment, resulting in ameliorated B-cell development and functionality and contributing to immunologic improvement in patients with WAS.

Keywords: B cell; Wiskott-Aldrich syndrome; gene therapy; lentiviral vector; primary immunodeficiency.

Publication types

  • Case Reports
  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autoantibodies / biosynthesis
  • B-Cell Activating Factor / genetics
  • B-Cell Activating Factor / metabolism
  • B-Lymphocyte Subsets / immunology
  • B-Lymphocyte Subsets / metabolism*
  • B-Lymphocyte Subsets / pathology
  • Bone Marrow / immunology
  • Bone Marrow / metabolism
  • Bone Marrow / pathology
  • Child
  • Child, Preschool
  • Gene Expression
  • Gene Expression Profiling
  • Genetic Therapy / methods*
  • Genetic Vectors
  • Hematopoietic Stem Cell Transplantation*
  • Hematopoietic Stem Cells / immunology
  • Hematopoietic Stem Cells / metabolism
  • Humans
  • Immunoglobulins / biosynthesis
  • Immunophenotyping
  • Infant
  • Lentivirus / genetics
  • Male
  • Recombinant Fusion Proteins / therapeutic use
  • Transduction, Genetic
  • Transplantation Conditioning
  • Transplantation, Autologous
  • Wiskott-Aldrich Syndrome / genetics
  • Wiskott-Aldrich Syndrome / immunology
  • Wiskott-Aldrich Syndrome / pathology
  • Wiskott-Aldrich Syndrome / therapy*
  • Wiskott-Aldrich Syndrome Protein / genetics*
  • Wiskott-Aldrich Syndrome Protein / immunology

Substances

  • Autoantibodies
  • B-Cell Activating Factor
  • Immunoglobulins
  • Recombinant Fusion Proteins
  • WAS protein, human
  • Wiskott-Aldrich Syndrome Protein
  • anti-CD20Fab-LDM protein