Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018133 (graft-versus-host disease)
 18,032 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Over the past decade, safety of blood has increased tremendously because of better donor screening as well as testing of the units for transmissible diseases. Component therapy has allowed more effective and economic use of blood. Whole blood is rarely used; instead, packed red cells, platelets, and fresh frozen plasma (FFP) are the most common components used. These products are further refined using irradiation and microaggregate filters and in the case of FFP, viral inactivation. Irradiation prevents transfusion-associated graft versus host disease, whereas microaggregate filters remove leukocytes, decreasing the rates of alloimmunization, febrile nonhemolytic (FNH) reactions, and cytomegalovirus (CMV) transmission. Autologous donation in older children probably provides the safest blood as far as transmissible diseases are concerned. More families request a directed donation and solicit physician help in deciding as well as making arrangements for autologous and/or directed donations. Transfusions of blood and blood components in children are often challenging and require a knowledge of physiologic changes in hemoglobin and blood volumes during different ages. The unique needs of neonates, immunocompromised patients, and patients with congenital hemolytic anemia (sickle cell, thalassemia) mandate that the pediatrician have an appropriate knowledge of transfusion volumes and choice of blood product as well as indications for transfusion.
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PMID:Pediatric transfusion therapy: practical considerations. 1079 77

The novel allogeneic transplant approach outlined in this chapter proposes the dual concepts that currently used intensive cytoreductive conditioning programs can be successfully replaced by nonmyeloblative immunosuppression and that stem cell grafts create marrow space for engraftment through subclinical GVH reactions. Immunosuppression can be conceptually divided into two parts, one targeted exclusively towards host cells before transplantation, and the other aimed at both host and donor T lymphocytes after transplantation. The resultant effect is to either establish mutual graft-host tolerance as reflected by stable mixed donor-host chimerism or accomplish complete donor chimerism. Preclinical studies have demonstrated the feasibility of this new approach in the context of MHC-identical transplants in young canines. Early data from the dog model of severe hereditary hemolytic anemia suggest that mixed chimerism can partially correct the phenotypic expression of disease, but that complete chimerism will be necessary to halt the continued hemolytic process of the host type minority red blood cell population. In contrast, mixed chimerism would be expected to correct disease manifestations of other severe hereditary red blood cell disorders such as sickle cell disease. The early results in human patients with hematological malignancies have demonstrated the feasibility of establishing hematopoietic engraftment using a nonmyeloblative conditioning regimen. Using this regimen, transplants were performed in the outpatient setting, and the need for transfusion support was minimal. Preliminary information suggests that mixed chimerism does not appear to be stable in this older patient population, with most patients progressing to full donor chimerism and a small minority rejecting. Complete disease responses and molecular remissions have been observed in a significant proportion of patients, suggesting that adoptive immunotherapy may not be necessary in most cases. However, in those patients that engraft with at least mixed chimerism and develop progression of the underlying malignancy, DLIs can be used for subsequent adoptive immunotherapy. The feasibility and safety of the outpatient approach for MHC-nonidentical transplantation has been demonstrated. Graft rejection appears to have been corrected by the addition of fludarabine to the nonmyeloablative conditioning regimen for the recipients of HLA-identical sibling allografts. Despite most recipients of MHC-nonidentical transplantation having sustained engraftment, some rejections have been observed. Studies are ongoing to identify the risk factors for rejection after unrelated HSCT to ensure uniform engraftment in future studies.
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PMID:Outpatient allografting in hematologic malignancies and nonmalignant disorders--applying lessons learned in the canine model to humans. 1190 97