Hi peonypixie and welcome to TiMS,
The chemotherapy drug, cytoxan, had an affect on your immune system, and because the cost of trials is so high, researchers must be very selective in which patients are admitted. Patients who had previous immune-modulating treatments, such as chemo, could skew the results of this study and make the results of stem cell therapy look better than they actually are in reality. There are usually always inclusion/exclusion criteria for every study. Hope this helps.