Sunday, January 28, 2007

+180 Article on Mixed Chimerism for WAS

Good news! I can't believe I found a medical article that addresses many of my questions regarding mixed chimerism for Wiskott Aldrich Syndrome. We're thankful that David's underlying disease (platelet disorder) was corrected by the donor cells. It appears he can function with long-term mixed chimerism of the lymphocytes. This is not official word from a doctor's mouth, so we'll keep updating the blog as we get more information.

Establishment of Complete and Mixed Donor Chimerism After Allogeneic Lymphohematopoietic Transplantation


"Long-term mixed chimerism is a frequent consequence of transplantation for treatment of immunodeficiencies that express pathologic lesions in the T-cell lineage, such as severe combined immunodeficiencies (SCIDs), Wiskott- Aldrich syndrome, and hemophagocytic lymphohistiocytosis. Even with conventional “ablative” protocols (eg, busulfan, clophosphamide, and etoposide), mixed chimerism in the peripheral blood is seen in approximately 50% of cases. After unrelated or alternative donor transplantation without T-cell depletion, full donor chimerism may be somewhat more common than it is after histocompatible sibling transplantation, perhaps because of a stronger graft-versus hematopoiesis effect. In these disorders: (1) mixed chimerism prior to day 100 does not predict rejection, (2) chimerism can fluctuate over time without specific interventions, and(3) mixed chimerism is usually compatible with full correction of the T-cell dysfunction, because the circulating T cells are completely, or predominantly, of donor type. Reversal of proportional donor-type engraftment from 5% to 100% has been observed. Generally speaking, engraftment of >10% donor cells may be adequate for functional correction of the underlying disease. An example of gradual increase in donor chimerism (without specific intervention) is illustrated in Figure 6, which represents the course of an 11-month-old boy who received an unrelated-donor cord blood transplant following conventional myeloablative chemotherapy for Wiskott-Aldrich syndrome. "

1 comment:

Mel Dahlgren said...

Praise God! The mixed chimerisms is another faith chapter in David's fascinating book of faith! This roller coaster ride sure has some scary drops and steep inclines! But God is faithful in keeping everything on the tracks!
I know you are aware of little Tyler McNally's roller coaster ride since his birth a month ago. You are so right Aimee, "Will He find faith on the earth?" I believe God is building that faith in His church through these trials.
Thanks for being the willing and faithful instruments in God's hands to help us all grow in that priceless faith! Love, Mel