Pneumocystis jiroveci pneumonia, once seen in 5–10% of patients, can be prevented by treating patients with oral trimethoprim-sulfamethoxazole for 1 week pretransplant and resuming the treatment once patients have engrafted. The risk of infection diminishes considerably beyond 3 months after transplant unless chronic Most GVHD transplant develops, centers requiring recommend continuous continuing immunosuppression. trimethoprim-sulfamethoxazole prophylaxis while patients are receiving any immunosuppressive drugs and also recommend careful monitoring for late CMV reactivation. In addition, many centers recommend prophylaxis against varicella zoster, using acyclovir for 1 year posttransplant. Treatment Transplantation of Specific Diseases Using Hematopoietic Cell Nonmalignant Diseases: Treatment Immunodeficiency Disorders By replacing abnormal stem cells with cells from a normal donor, hematopoietic. | Chapter 108. Hematopoietic Cell Transplantation Part 7 Pneumocystis jiroveci pneumonia once seen in 5-10 of patients can be prevented by treating patients with oral trimethoprim-sulfamethoxazole for 1 week pretransplant and resuming the treatment once patients have engrafted. The risk of infection diminishes considerably beyond 3 months after transplant unless chronic GVHD develops requiring continuous immunosuppression. Most transplant centers recommend continuing trimethoprim-sulfamethoxazole prophylaxis while patients are receiving any immunosuppressive drugs and also recommend careful monitoring for late CMV reactivation. In addition many centers recommend prophylaxis against varicella zoster using acyclovir for 1 year posttransplant. Treatment of Specific Diseases Using Hematopoietic Cell Transplantation Nonmalignant Diseases Treatment Immunodeficiency Disorders By replacing abnormal stem cells with cells from a normal donor hematopoietic cell transplantation can cure patients of a variety of immunodeficiency disorders including severe combined immunodeficiency Wiskott-Aldrich syndrome and Chédiak-Higashi syndrome. The widest experience has been with severe combined immunodeficiency disease where cure rates of 90 can be expected with HLA-identical donors and success rates of 5070 have been reported using haplotype-mismatched parents as donors Table 108-3 . Table 108-3 Estimated 5-Year Survival Rates Following Transplantation Disease Allogeneic Autologous Severe combined immunodeficiency 90 N A Aplastic anemia 90 N A Thalassemia 90 N A Acute myeloid leukemia First remission 55-60 50 Second remission 40 30 Acute lymphocytic leukemia First remission 50 40 Second remission 40 30 Chronic myeloid leukemia