INVESTIGADORES
DEWEY Ricardo Alfredo
congresos y reuniones científicas
Título:
Correction of Wiskott-Aldrich syndrome by hematopoietic stem cell gene therapy.
Autor/es:
K. BOZTUG; M. SCHMIDT; A. SCHWARZER; P. P. BANERJEE; M. BÖHM; R. BEIER; I. AVEDILLO DÍEZ; R. A. DEWEY; C. BALL; A. NOWROUZI; S. NAUNDORF; K. KUHLCKE; R. BLASCZYKS; M. ROSE; C. FRAZER; M. LIESL; R. FERRARI; M. ABBOUD; W. AL-HERZ; I. KONDRATENKO; L. MARODI; J.S. ORANGE; C. VON KALLE; C. KLEIN
Lugar:
Orlando
Reunión:
Congreso; 52nd American Society of Hematology Annual Meeting and Exposition.; 2010
Resumen:
Wiskott
Aldrich Syndrome is a life-threatening immune-disorder characterized by
bleeding secondary to microthrombocytopenia, immunodeficiency, autoimmunity,
and susceptibility to lymphoma. A clinical gene therapy protocol using a GALV
pseudotyped MLV-derived retroviral vector was developed at Hannover Medical
School. We here present
an analysis of ten patients treated in this trial between 2006 and 2009. All
patients had evidence of engraftment of WASP-positive hematopoietic progenitor
cells except for one patient in whom an insufficient number of CD34+ cells
could be harvested. WASP expression was determined in myeloid and lymphoid
cells as well as in CD34+ hematopoietic progenitor cells using Western Blot and
FACS analysis, respectively. While the percentage of WASP-positive myeloid
cells was relatively stable over time (range 10 to 60%), a marked increase over
time in the percentage of WASP-positive T lymphocytes and NK cells was observed,
resulting in more than 80% of WASP-positive lymphoid cells 12 months after gene
therapy.
Early after gene therapy,
an increase in thrombocyte counts was observed in all patients. Furthermore,
the majority of peripheral thrombocytes showed evidence of WASP expression,
detectable as early as 3 months after gene therapy. Functional immune
reconstitution was documented in dendritic cells (podosome formation), T cells
(proliferation in response to CD3-signaling), and NK cells (formation of
immunological synapse and NK cell killing activity). TCR Vb spectratyping
analyses showed in improvement of receptor skewing upon gene therapy in some
patients. A clinical benefit was notable in all patients with the exception of
the patients with insufficient engraftment of genetically corrected progenitor
cells: eczema, bleeding diathesis and immunodeficiency resolved. Strikingly,
the various autoimmune phenomena which the patients in this trial had shown
prior to gene therapy resolved when the majority of T lymphocytes were positive
for WASP expression, and a particular advantage of WASP-positive regulatory T
lymphocytes (Tregs) could be observed at this point, suggesting a crucial role
in WASP reconstitution in Tregs for autoimmnity resolution. Repetitive
bone marrow examinations did not reveal morphological or cytogenetic
alterations. Comprehensive insertion site analysis using 454 pyrosequencing
demonstrated vector integration that targeted multiple genes controlling
growth, development and immunological responses in a persistently polyclonal
hematopoiesis.
In sum, hematopoietic stem
cell gene therapy for Wiskott-Aldrich Syndrome is feasible and effective at
correcting the various cellular defects implicated in this disease. Our trial
provides the first proof-of-principle for gene therapy in Wiskott-Aldrich
syndrome and provides evidence that gene therapy may be effective at correcting
disorders involving autoimmunity and/or platelets. Prospective monitoring is
used in this trial to determine the long-term efficacy and safety profile of
this experimental therapeutic approach in Wiskott-Aldrich syndrome.