Results of Transplanting Bone Marrow from Genetically Identical Twins into Patients with Aplastic Anemia

15 January 1997 | Volume 126 Issue 2 | Pages 116-122

Background: Aplastic anemia is caused by several diverse factors, including a lack of or defective hematopoietic stem cells, immune abnormalities, and disorders of the bone marrow microenvironment. The outcome of transplanting bone marrow from genetically identical twins into patients with aplastic anemia may help define how frequently these factors play a role in this condition.

Objective: To determine the outcome of transplanting bone marrow from genetically identical twins into patients with aplastic anemia.

Design: Observational study.

Setting: 31 centers participating in the International Bone Marrow Transplant Registry.

Patients: 40 patients with aplastic anemia who received bone marrow transplants from their genetically identical twins between 1964 and 1992.

Intervention: 23 patients received their first bone marrow transplant without pretransplantation conditioning; 17 received it after pretransplantation conditioning with cyclophosphamide alone or combined with other drugs or radiation. Six patients received post-transplantation immunosuppressive therapy with methotrexate, cyclosporine, and corticosteroids, alone or in combination.

Measurements: Outcomes of transplantation, including hematologic recovery and survival.

Results: Seven of 23 patients who received their first transplant without receiving conditioning had sustained complete hematologic recovery. One of 16 patients who did not have complete recovery after the first transplantation recovered after a second transplantation, which was not preceded by conditioning. The other 15 patients had two to five transplantations that were preceded by conditioning; in 13 patients, sustained bone marrow function was recovered. Twelve of 17 patients whose first transplantation was preceded by conditioning had sustained complete hematologic recovery. The likelihood of hematologic recovery was greater in patients who had conditioning before the first transplantation (P = 0.033). The actuarial 10-year survival rate for the 40 patients was 78% (95% CI, 59% to 92%). The survival rate was higher in patients who did not have conditioning before the first transplantation (patients without conditioning, 87% [range, 65% to 99%]; patients with conditioning, 70% [range, 47% to 89%]; P = 0.037).

Conclusions: Most patients with aplastic anemia recover bone marrow function after receiving a transplant from a genetically identical twin. Pretransplantation conditioning may increase the chance of bone marrow recovery but does not seem to improve survival.

Author and Article Information

For author affiliations and current author addresses, see end of text.
Acknowledgments: The authors thank Melodee L. Nugent, MA, for data analysis and Dr. Mortimer M. Bortin, who provided guidance in design and initiation of this study before his death in July 1994.
Grant Support: By Public Health Service grant PO1-CA-40053 from the National Cancer Institute, the National Institute of Allergy and Infectious Diseases, and the National Heart, Lung and Blood Institute; by contract CP-21161 from the National Cancer Institute of the U.S. Department of Health and Human Services; and by grants from Alpha Therapeutic Corp.; Amgen, Inc.; Applied Immune Sciences; Armour Pharmaceutical Co.; Astra Pharmaceutical; Baxter Healthcare Corp.; Bayer Corp.; Biogen; Blue Cross and Blue Shield Association; Lynde and Harry Bradley Foundation; Bristol-Myers Squibb Co.; Frank G. Brotz Family Foundation; the Cancer Center of the Medical College of Wisconsin; Center for Advanced Studies in Leukemia; Charles E. Culpeper Foundation; Eleanor Naylor Dana Charitable Trust; Eppley Foundation for Research; Genentech, Inc.; Glaxo Wellcome Co.; Hoechst Marion Roussel, Inc.; Immunex Corp.; Janssen Pharmaceutica; Kettering Family Foundation; Kirin Brewery Co.; Robert J. Kleberg Jr. and Helen C. Kleberg Foundation; Herbert H. Kohl Charities, Inc.; Eli Lilly Co. Foundation; Nada and Herbert P. Mahler Charities; Milstein Family Foundation; Milwaukee Foundation-Elsa Schoeneich Research Fund; Samuel Roberts Noble Foundation; Ortho Biotech Corp.; John Oster Family Foundation; Elsa U. Pardee Foundation; Jane and Lloyd Pettit Foundation; Alirio Pfiffer Bone Marrow Transplant Support Association; Pfizer, Inc.; Pharmacia Upjohn; RGK Foundation; Sandoz Pharmaceuticals; Schering-Plough International; Walter Schroeder Foundation; Stackner Family Foundation; Starr Foundation; Joan and Jack Stein Charities; and Wyeth-Ayerst Laboratories.
Requests for Reprints: Mary M. Horowitz, MD, MS, International Bone Marrow Transplant Registry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226.
Current Author Addresses: Drs. Hinterberger and Hinterberger-Fischer: Donauspital im Sozialmedizinischen, Zentrum Ost 2 Med. Abteilung, Langobardenstrasse 122, A-1220 Vienna, Austria. Drs. Rowlings and Horowitz: International Bone Marrow Transplant Registry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226.