While reading again, I found these articles. They discuss cases where Hairy Cell Leukemia (HCL) mimics Aplastic Anemia. I thought it was interesting in reference to this post for three reasons: 1) HCL is often easily put into remission with one round of chemo, so is easier to treat than most cancers. Aplastic Anemia often also responds to one round of immunosuppression; 2) HCL sometimes presents first as Aplastic Anemia; & 3) refractory cases of HCL are treated with Rituximab, and sometimes Alemtuzumab (Campath) and some people on the board had success with the NIH Campath trial for refractory Aplastic Anemia:
Aplastic anemia terminating in hairy cell leukemia. A report of two cases.
http://www.ncbi.nlm.nih.gov/pubmed/6697293
Persistent remission after immunosuppressive therapy of hairy cell leukemia mimicking aplastic anemia: two case reports.
http://www.ncbi.nlm.nih.gov/pubmed/12774930
In particular, I thought you would find the last sentence of the second citation interesting:
"Sustained improvement of hematopoiesis in such B-cell malignancies after ATG/ ALG therapy suggests that the mechanisms underlying successful immunosuppressive therapy for aplastic anemia may involve B-cell suppression, inhibiting hematopoietic stem cells."