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Outcome Of Hematopoietic Stem Cell Transplantation For Wiskott-Aldrich Syndrome

Track: Poster Abstracts
Saturday, March 1, 2014, 6:45 PM-7:45 PM
Longhorn Hall E (Exhibit Level 1) (Gaylord Texan)
Sakara Hutspardol, MD , Haematology/Oncology, Hospital for Sick Children, Toronto, ON, Canada
Adam Gassas, MD, MBChB, MSc, MRCP, DCH , Haematology/Oncology, The Hospital for Sick Children, Toronto, ON, Canada
John Doyle, MD FRCPC FAAP , Paediatric Hematology/Oncology, CancerCare Manitoba, Winnipeg, MB, Canada
Muhammad Ali, MD , Haematology/Oncology, The Hospital for Sick Children, Toronto, ON, Canada
R. Maarten Egeler, MD, PhD , Haematology/Oncology, Hospital for Sick Children, Toronto, ON, Canada
Eyal Grunebaum, MD , Immunology and Allergy/ BMT Program, Hospital for Sick Children, Toronto, ON, Canada
Tal Schechter-Finkelstein, MD , Haematology/Oncology, Hospital for Sick Children, Toronto, ON, Canada
Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency presented with eczema, microthrombocytopenia, autoimmune disorders, recurrent infections, and subsequent malignancies. Little is known on late complications following hematopoietic stem cell transplant (HSCT) in this population. In a single-institutional retrospective study of 17 WAS patients who underwent HSCT between January 1992 and December 2012, we evaluated autoimmune manifestations, serious infections, and graft-versus-host disease (GVHD).

Median age at HSCT was 2.17 years (range 0.28-12.38). Nine (52.9%) and eight patients (47.1%) received bone marrow and umbilical cord blood, respectively.  Fourteen patients (82.3%) underwent HSCT from alternative donors including unrelated cord, mismatch family, and match unrelated donors. Only 2 match sibling (11.7%) and one match related (5.9%) were used as donors. Median follow-up time was 7.05 years (range 1.82-19.99).

Two patients (11.7%) died 1 month and 2.1 years post HSCT due to CMV interstitial pneumonitis and severe Streptococcus pneumoniae sepsis, respectively. Overall survival (OS) at 2-year was 87.4%. HLA mismatch and stem cell source were not significant factors for OS (p= 0.325 and 0.886, consecutively). In multivariate analysis, age at HSCT, HLA mismatch, and stem cell sources were also not significant.

Five patients (29.4%) developed acute GVHD grade II-IV. The incidence of acute GVHD (grade II-IV) was higher when using bone marrow as a stem cell source (p= 0.029). Eight (47.1%) and three patients (17.6%) developed limited and extensive GVHD. The incidence of chronic GVHD did not differ by age at HSCT, HLA mismatch, and stem cell source.

Mixed donor chimerism was temporarily observed in 4 patients (23.5%). Immunosuppressant was adjusted without donor lymphocyte infusion. Donor chimerism was subsequently improved.

We observed chronic GVHD-independent autoimmune thrombocytopenia in 4 patients (23.5%). One of those four also developed warm and cold agglutinin positive autoimmune hemolytic anemia.  All episodes of autoimmune thrombocytopenia occurred in patients who received cord blood transplantation. Mixed donor chimerism was observed in 3 of those 4 patients who had persistent thrombocytopenia. Only one patient who developed autoimmune thrombocytopenia and hemolytic anemia received treatment of plasmapheresis and rituximab. This patient eventually required regular intravenous immunoglobulin infusion due to persistent hypogammaglobulinemia. Thrombocytopenia was gradually subsided with the improvement of donor chimerism in all patients. No malignancy occurred post-HSCT in this retrospective cohort.

We report an excellent result using a majority of unmanipulated unrelated and mismatched family donors in this study. Cytopenias were observed in conjunction with utilization of cord blood stem cells and mixed donor chimerism.

Disclosures:
Nothing To Disclose
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