Better, then less good, during steroid taper?

[h202]

Our son started a steroid taper 2.5 weeks ago.  First 7 days on 2mg/kg, next 7 days on 1mg/kg, next 7 days on .5mg/kg, and last 7 days on .5mg/kg every 2 days.  Within hours of the first dose, we saw a huge improvement. First 12 days were consistently fantastic. Mood was greatly improved, anxiety reduced (but not entirely), son was totally amenable to stopping his stereotypies (he has what we initially thought were tics, but were in fact very complex stereotypies involving full body movements along with imagining sessions).   On the 13th day (six days after the first decrease, and 1 day before the next decrease) we saw a return of some issues -- some tears, increased anxiety and irritability, and a minor reemergence of the stereotypie.  So we went from maybe 90% improvement to 60% -- all while still on the taper.  

When we tried a 5-day steroid burst a few months ago, his symptoms disappeared on day 5 (right before the last dose) and stayed away for 3 days before total reemergence.  

What could account for his initial improvement on steroids and then reemergence of issues on day 13?  The obvious answer is that his symptoms seem to be tracking the tapering of the steroid.  But if we're addressing autoimmune inflammation, wouldn't we expect some continued benefit without tracking, almost day by day, the tapering?  My fear is the benefits we were seeing the first 13 days were in fact simple positive side effects of steroids (which, for many people taking it for asthma etc, produce a "high" that gives them a good mood and more energy) and not necessarily anti-inflammatory properties relating to autoimmune.  

Any thoughts?  

[bobh]

I would guess that we don't know enough about how everything works to pinpoint the difference between the two options that you suggested.  The way the immune system works alone is particularly complicated, and that's just what they understand.

From a practical point of view, what would  you do differently if you knew the true answer to your question?  The child shouldn't stay on (a significant dose of) steroids over a long haul, so this is a rescue option.  Or, is this trial about proof of autoimmunity?