Although cd34+ is a measurement of how well you are engrafting, it does not necessarily correlate closely to relapse. Also, getting the donor chimerism numbers can and usually is done periodically after transplant without going through the trial.
As Neil stated, the safety and efficacy of revlimid is pretty well documented in MDS as it is one of only 3 drugs currently approved for the treatment of MDS, but its approval is limited to the -5q patients. In non -5q patients, it has about a 25-30% improvement rate in lower risk patients primarily. One interesting note is that even when it does not work from a clinical perspective - ie improvement in blood counts - it sometimes has the effect of removing chromosomal abnormalities.
Revlimid typically helps RBC, but benefits are also seen in patients in the platelet and wbc lines as well. If I recall, revlimid may also have some positive benefit in patients with fibrosis. I know that many years back I read a study that showed this as a potential benefit.
Revlimid is known as an immune modulatory drug, but its actual mechanism of action isn't really clearly understood at this point from what I know.
Like Neil, I think that it is very much worth a discussion with your doctor as a potential option, especially since I think you were considered high risk at transplant. The 21 day dosing cycle sounds like the standard cycle for Revlimid, but I don't know anything about the dosing level.
Please share any information you can about the trial when you get more information, and as always, good health and strong recovery to you!
MDS RCMD w/grade 2-3 fibrosis. Allo-MUD Feb 26, 2014. Relapsed August 2014. Free and clear of MDS since November 2014 after treatment with Vidaza and Rituxan. Experiencing autoimmune attack on CNS thought to be GVHD, some gut, skin and ocular cGVHD. Neuropathy over 80% of body.