The Wait for Engraftment

In bone marrow transplant medicine, there is a period doctors call engraftment — and it may be the closest thing in modern science to a parable about faith.

Here is what happens. First, chemotherapy destroys the patient's existing bone marrow. Every blood-forming cell is wiped out. Then donor stem cells are infused through an IV — it looks surprisingly ordinary, like a simple blood transfusion. But then comes the hard part: the wait.

For two to four weeks, the patient lives in a sterile hospital room with virtually no immune system. The old marrow is gone. The new marrow has not yet proven itself. Doctors watch the daily blood counts, looking for the moment when neutrophils — those frontline soldiers of the immune system — begin to rise. Until they do, the patient has nothing but the promise that those transplanted cells are silently migrating to the hollows of their bones, taking root, beginning to build a new life from the inside out.

The writer of Hebrews understood this kind of waiting. "Faith is the substance of things hoped for, the evidence of things not seen." Between the destruction of the old and the proof of the new, there is a gap — and that gap is where faith lives. The transplanted cells are already at work. The evidence just has not surfaced yet.

If you are in that waiting room today — the old gone, the new not yet visible — take heart. Engraftment is happening. The Healer is at work in the hidden places, building something your blood counts cannot yet confirm.