Defining Transplant "Success"

Really interesting insights from Dr. Whitley about successful Hurler treatment.

Is success defined by the degree of engraftment (the percent of total cells that are donor cells), or the enzyme activity of the donor cells relative to a "normal" kid?

According to Dr. Whitley, in Hurler patients, enzyme production yield is less important than percent engraftment. In most patients, even 25-50% enzyme yield is sufficient for success. Partial engraftment is sub-optimal, but not the end of the world. Since Gracie is small, degree of graft uptake is more likely to be higher.

We keep hearing an anecdote from numerous folks about a 21 year old in North Dakota, who is living a normal and happy life (he was here for a check-up last week). Turns out his graft was only partial and his donor already only had 50% enzyme yield. He, as a result has about 25% on the enzyme yield of a "normal" kid. Yet, he still lives a great life.

So, I'm confused now, how about you? :) Really interesting and encouraging though.