Dear Susan - my son had much the same experience as you have had. He had a stem cell transplant as well - but the B cell was back within a year. He then went to the wonderful
Mayo Clinic and had a T-Cell transplant. That was in August 2018, and just had his 2 year checkup! All seems good. We are so greatful to the Mayo!
Thinking of you and let us know what your next step will be.