Luke has cyclic neutropenia, which is how we are explaining the up and down bounce in his white blood cell count / absolute neutrophil count. Fortunately, Luke has been anti-symptomatic at this point and he hasn't encountered any odd rashes or infections yet that have been concerning. We are monitoring his WBC and ANC with a monthly blood draw for now. Hopefully it's something he outgrows, but it can be life-threatening and is very serious if an infection occurs. We will continue to learn and pray that Luke doesn't develop anything serious.
This article sums it up nicely: Guidelines for Diagnosis and Treatment of SDS
A note to self: I discovered this comment on a thread about neutropenia recently and wanted to have this info to review next time I get fired up and motivated to start using supplements....