Patient Vignette - Part 2
These cases illustrate how HSCT can replace (components of) a defective immune system, although the specific approach of HSCT will be different in this diverse group of primary immunodeficiency disorders. For example, patients with XSCID are considerably less capable of rejecting allogeneic stem cells than patients with CGD, who have an essentially normal lymphocyte compartment (as far as rejection is concerned).
In addition to documenting correction of a defective immune system, these assays can serve as a quantitative monitor of engraftment if the assay is sufficiently sensitive in distinguishing between normal and abnormal cells (for example the detection of normal neutrophils and neutrophils with defective oxidative burst, as occurs in CGD). These figures serve as good examples of the "Before and After Principle".
