From my private research and subsequent use of herbs in the treatment of my son's AA, a herb commonly available used for treating AA is the astralagus, which is believed to be a natural telomerase activator.
It is generally believed that short telomeres result in chromosome instability, hence there is also a potential mechanism for telomere lengthening to protect against blood diseases such as AA and blood cancers in astralagus.
You can get more details by googling for astralagus or from wikipedia as well.
Some interesting studies on aplastic anemia in relation to tolemerase on this include:
Telomerase Mutations in Aplastic Anemia
Telomerase gene mutation screening in Chinese patients with aplastic anemia
Mutations in telomerase catalytic protein in Japanese children with aplastic anemia
Peter Lim, Dad to Stan, age 17 at time of dx Feb 2002VSAA; tx. ATG, cyclosporine, predisone; alternative herbal supplm & shark liver oil, off all meds 5/2002 normal blood counts. Only on shark liver oil.