Hi Dan - they gave me Rituxin when I had GVHD (skin rash pretty much everywhere) - at the time my counts were also low - the Rituxin cleared up the GVHD and my counts started rising - sounds very similar to your experience, minus the Vidaza - I also had some significant mylelofibrosis.
Were you always 100% donor? It worries me that I went down from 100% to 90%. I won't be surprised if they want to give me Vidaza regardless of the next BMB... I'm encouraged by how well your doing!
Lower risk MDS diagnosed 2012. Recurring skin nodules treated with prednisone, otherwise watch and wait. HG dropped from 11.5 to 8.7. Kept going down to 5. Vidaza didn't work. BMT from MUD on September 10 2015