Methotrexate is frequently used in the conditioning regimen for stem cell transplant to suppress the immune system and try to prevent acute GVHD. It may have been used for other purposes in MDS as well, but it is not commonly used for treatment apart from stem cell transplant at least not so far as I know.
The other place that I have seen it used is to treat ITP and RA. It would seem like if a person's MDS was immune mediated that it could be used for treatment as well.
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.