MPO deficiency can cause some infection, so they probably just want to perform a sonogram and see if any infections have appeared. If so, they will give you antibiotics and you will be okay. If not, then you are fine. Here's some more reading: http://www.wellness.com/reference/allergies/myelop... I hope this helps!
You can help the HubPages community highlight top quality content by ranking this answer up or down.