Stable mixed chimerism after hematopoietic stem cell transplantation in Wiskott-Aldrich syndrome

Clinical Features and Outcomes of 23 Patients with Wiskott-Aldrich Syndrome: A Single-Center Experience

Objective

Wiskott-Aldrich syndrome (WAS) is an X-linked primary immune deficiency characterized by microthrombocytopenia, eczema, and recurrent infections. We aimed to evaluate the clinical features and outcomes of a WAS cohort.

Materials and Methods

We retrospectively evaluated the clinical courses, immunological features, treatments, and outcomes in a total of 23 WAS patients together with data related to 11 transplanted cases among them between 1982 and 2019.

Results

Before admission, 11 patients (48%) were misdiagnosed with immune thrombocytopenia. WAS scores were mostly 4 or 5. Eleven patients were transplanted and they had an overall survival rate of 100% during a median follow-up period of 8.5 years (range: 8 months to 20 years). Five patients who were not transplanted died at a median of 7 years (range: 2-26 years). Nontransplanted patients had high morbidity due to organ damage, mostly caused by autoimmunity, bleeding, and infections. Two novel mutations were also defined.

Conclusion

All male babies with microthrombocytopenia should be evaluated for WAS. Hematopoietic stem cell transplantation should be performed at the earliest age with the best possible donors.

Outcomes after Allogeneic Transplant in Patients with Wiskott-Aldrich Syndrome

/kg (range, .3 to 7.9). The median times to neutrophil and platelet engraftment were 19 days (range, 13 to 27) and 18.5 days (range, 12 to 31), respectively. The rate of overall survival was 92% with median follow-up of 67 months (range, 3 to 146). Two patients developed grade IV acute graft-versus-host disease, and 1 died on day +99. Five of 12 patient's (42%) had mixed donor chimerism (range, 12% to 85%) at day +180. None of the pretransplant patient parameters was predictive of mixed chimerism. Nonetheless, of these 5 patients, 2 had normalization of the platelet count despite the mixed chimerism, 2 had full donor chimerism after receiving a second transplant with the same donor, and 1 remains transfusion dependent awaiting a second transplant. Hence, even with a significant rate of mixed chimerism, HSCT provides substantial benefit to WAS patients, with excellent overall survival.

Successful Reduced Intensity Allogeneic Transplant With Full Donor Chimerism and Good Quality of Life in Adolescent Patient With Wiskott-Aldrich Syndrome

Wiskott-Aldrich syndrome (WAS) is an X-linked disease characterized by microthrombocytopenia, eczema, immune deficiency, and autoimmune phenomena. Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment. Myeloablative conditioning is the most common regimen used for HSCT in patients with WAS to avoid the risk of mixed donor chimerism and autoimmunity post-HSCT. There is limited data on the use of reduced intensity conditioning for HSCT in patients with WAS. Here, we report a case with severe phenotype of WAS transplanted successfully with reduced intensity conditioning, which is an acceptable conditioning regimen and can be considered in patients with WAS with significantly impaired organ functions.

Early transplantation of unrelated cord blood in a two-month-old infant with Wiskott-Aldrich syndrome

This report exemplified a success of unrelated CBT in a two-month-old boy with Wiskott-Aldrich Syndrome. Umbilical cord blood was chosen as the stem-cell source because of its immediate availability and reduced tendency to cause GVHD. The conditioning regimen was cyclophosphamide, busulfan, and antithymocyte globulin. GVHD prophylaxis consisted of cyclosporin and methylprednisolone. The patient received an HLA 1-locus-mismatched cord blood unit, and the total number of infused nucleated cells was 11.14 x 10(7)/kg. Neutrophil engraftment was achieved on day +11, and a platelet count greater than 50 x 10(9)/L was achieved on day +71. He is currently alive and doing well at nine months post-transplant and free of any bleeding episodes. This case suggests that unrelated donor CBT may be safe and technically feasible, even in early infancy, when an appropriately matched related or unrelated donor is unavailable.

Stem cell transplantation in primary immunodeficiencies

PURPOSE OF REVIEW

To review indications and outcomes of haematopoietic stem cell transplantation in primary immunodeficiencies, in light of recent advances in the field.

RECENT FINDINGS

Remarkable improvements in the outcome of haematopoietic stem cell transplantation in primary immunodeficiencies have recently been reported. This is a result of the successful use of alternative donors and more effective strategies to prevent and treat complications. These advances have now permitted the indications for haematopoietic stem cell transplantation to be extended in primary immunodeficiencies.

SUMMARY

The optimal results of haematopoietic stem cell transplantation in primary immunodeficiencies have long been obtained with related human leukocyte antigen-identical donors, an option limited to a minority of patients. Transplantation from mismatched related donors has been used with good results mainly in infants with severe combined immune deficiency, but has been associated with significantly delayed or incomplete immune reconstitution. Recent data indicate that transplantation from matched unrelated donors and cord blood transplantation represent valid alternatives, which can be used in all forms of severe primary immunodeficiencies. This, along with careful monitoring of infections, coupled with preemptive treatment, has resulted in a significant improvement in the outcome of haematopoietic stem cell transplantation for severe forms of primary immunodeficiencies.