HTB South

Sad news regarding attempt to duplicate the cure achieved in Timothy Brown

Richard Jefferys, TAG

In April, doctors at the University of Minnesota announced that they were attempting to reproduce the cure achieved in Timothy Brown in a 12-year old boy with HIV and leukemia who required a stem cell transplant. [1]

Due to the challenges associated with identifying appropriate adult stem cell donors homozygous for CCR5 delta-32 (as was done for Brown), the Minnesota team—led by Dr. John Wagner—obtained cord blood stem cells from the limited available supplies that have been screened for the mutation (the current status of screening efforts is described in a recent review article). [2] Permission was obtained from the Food and Drug Administration (FDA) to conduct the procedure, and it was performed on April 23rd.

On July 12th, the University of Minnesota reported that the boy, Eric Blue, died July 5th from complications associated with transplant. [3] Blue developed severe graft-versus host disease (GVHD), a known risk associated with stem cell transplantation. In the news stories, the doctors express their commitment to honoring Blue’s bravery by learning from his case, and highlight the need to expand screening of stored cord blood units for CCR5 delta-32 in order to increase the possibility of identifying sources that are suitably HLA-matched for potential HIV-positive recipients.

Cord blood stem transplantation is an evolving field, but current practice is based on matching 6 HLA antigens (fewer than are required for adult stem cell transplants), with a 6:6 match typically viewed as ideal and 4:6 as the minimum acceptable (although some resource websites cite 3:6 as “unlikely, but possible”). [4]

There are additional complexities related to the direction of the mismatch and the dose of cord blood that is available. Although the issue does not yet seem to be entirely resolved, it has also been reported that limited mismatches may lead to superior anti-cancer effects under some circumstances. One aspect of Eric Blue’s procedure that has not been specifically addressed in the news stories or the University of Minnesota’s coverage is the extent to which the CCR5 delta-32 homozygous cord blood source was HLA-matched. [5]

In order to provide guidance for future attempts to cure HIV-positive people with cancers using CCR5 delta-32 homozygous cord blood, it will be important for the doctors and researchers that were involved to report the details of the case.

References

  1. University of Minnesota news. Revolutionary treatment begins. (April 2013)
    http://www1.umn.edu/news/features/2013/UR_CONTENT_440332.html
  2. Petz LD et al. Hematopoietic cell transplantation with cord blood for cure of HIV infections. Biology of Blood and Marrow Transplantation Volume 19, Issue 3, pages 393-397, March 2013.
    http://www.bbmt.org/article/S1083-8791(12)00433-8/abstract
  3. French R. StarTribune Local. Boy, 12, dies after undergoing historic transplant at U to treat HIV and leukemia. (12 July 2013).
    http://www.startribune.com/local/215290391.html
  4. Cord Blood 101. Finding a Match – Knowing the difference between related and non-related stem cells. (02 September 2010).
    http://www.blog.viacord.com/finding-a-match-knowing-the-difference-between-related-and-non-related-stem-cells/
  5. University of Minnesota. Pediatric patient dies after undergoing historic transplant at U of M. UM Health Talk. (13 July 2013)
    http://www.health.umn.edu/healthtalk/2013/07/13/pediatric-patient-dies-after-undergoing-historic-transplant-at-u-of-m/

Links to other websites are current at date of posting but not maintained.