Felix’s Condition and Treatment: An Explanation

For those who wanted a better understanding of Felix’s condition, and the treatment options we’re exploring, here’s a more detailed explanation. This is my understanding of it, from a totally non-medical perspective, so you’ll have to forgive me if some of the details are slightly off.

So as you know, Felix was diagnosed with severe combined immunodeficiency (SCID), which was caught via newborn screening.

SCID is a genetic disorder that Felix inherited from us — Ben and I, it turns out, are both carriers. SCID is actually unusually common among the Mennonite population, though I’d never heard of it before Felix was diagnosed.

There are 10-15 different kinds of SCID, and Felix has the most common and most serious kind — SCID ADA. A mutation in his chromosomes prevents his body from creating ADA (Adenosine deaminase), an enzyme required to make T-lymphocytes, which are needed to fight off infections. The initial blood test showed that he had almost no T-lymphocytes.

On other words, Felix has virtually no immune system. As a result, even bacteria, viruses and fungi that pose little problem to the rest of us can be deadly. Something as ordinarily harmless as the herpes simplex virus (i.e. cold sores) can kill him. If left untreated, babies with SCID don’t make it to their second birthdays as a result of frequent and serious infections.

That’s why for now, Felix is in isolation in the hospital, so that he can’t catch anything. He’s also being treated with antibiotics for the (so far mild) infections he did pick up in his bladder and lungs. He also needs to be on a really low dose of oxygen right now, because his breathing is slightly impaired from the infection. His eating has been affected as well, so that he may need a feeding tube if he doesn’t improve.

Treatment Options

The most effective and long-term treatment for all forms of SCID is a bone marrow transplant (BMT). This treatment essentially involves taking the working immune system of a healthy person and transplanting it into the patient. The patient must first undergo chemotherapy to wipe out any of his original immune system and to “make room” for the new one.

By far, the most effective BMT involves a matched sibling. If the sibling is a match, a transplant typically has an 85% success rate. I have come into contact with two families who have experienced miracles thanks to sibling transplants. Lydia (along with me and Ben) was tested two weeks ago to see if she was a match. This was our greatest hope.

Unfortunately, we got the news on Wednesday that she’s not a match. (Ben and I weren’t even close.) We were devastated to get the news. Now we have to look at other options. Fortunately, there still are a few.

First, because Felix has ADA SCID, he can actually receive injections of the missing ADA enzyme. Now that we know a sibling BMT is not an option, we are pursuing that option immediately, and hoping he can start getting the treatment in the next week or two. Most patients begin to improve after a month or so as the immune system builds up, and we’re hoping to see his lungs and his eating improve enough that he won’t need oxygen or a feeding tube. If he gets healthy enough, we might actually be able to take him home in a few months!

However, ADA injections are generally only effective for a year or two, at which point they begin to wear off. So we still need to look into long-term solutions.

The first is a BMT from an unrelated matched donor. Because we’re Mennonite, we actually have a pretty good chance of finding such a donor — there are many in the bank, in large part because many Mennonite children have already been affected by SCID and their families tested. We’re more likely to find a match within our own ethnic group. Unfortunately, though, the success rate for BMT’s with unrelated donors is a lot lower — it has typically been more like 50-70%. (Our doctor pointed out, though, that these figures all come from children who were very sick at the time of the transplant. Felix is the first to have been caught before he was very sick. He has an enormous head start.)

The biggest problem with all BMT’s, but especially unrelated ones, is that the healthy new transplanted cells can attack the patient in what is called graph-versus-host disease.

So another option for SCID ADA patients is something called gene therapy. It’s a very new, cutting-edge, experimental kind of treatment that involves using the patient’s own bone marrow. It’s a modification of a BMT that attempts to avoid graph-versus-host disease: bone marrow is taken from the patient, the genes are corrected, and then transplanted back into the patient. This treatment is only being done in three places in the world: Los Angeles; London, England; and Milan, Italy.

Because it’s so new and experimental, it’s hard to say how successful it is, though I’m told the outcomes look good. The other advantage is that the cost of treatment would all be covered, since the researchers want more opportunities to try it.

So these are the options we’re considering. We have a few months to learn more about them and decide. Obviously, they’re all terrifying, as they all involve risking our child’s life. It’s difficult that we have to grapple with percentages of survival.

As of right this moment, though, we’re feeling hopeful. At least there are options. (Our feelings could be different by tomorrow).

And for now, Felix is still doing quite well. He’s a pretty content guy, sleeping a lot but with plenty of alert time, and he’s easy to soothe when something upsets him. He’s handling all of this stuff amazingly well.

And we’re just so grateful for the amazing people — doctors, nurses, family, and friends — supporting us through this all.