8/14/2019 Peripheral Blood Stem Cell

1/6

PERIPHERAL BLOOD STEMPERIPHERAL BLOOD STEM

CELLCELL

TRANSPLANTATIONTRANSPLANTATION

(PBSCT) AND BONE(PBSCT) AND BONE

MARROWMARROWTRANSPLANTATION BMT)TRANSPLANTATION BMT)

Jeo thomasJeo thomas

8/14/2019 Peripheral Blood Stem Cell

2/6

PBSCT and BMT are therapeutic modalities that offer the possibilityPBSCT and BMT are therapeutic modalities that offer the possibilityof cure for some patients with hematologic disorders suchof cure for some patients with hematologic disorders suchas severe aplastic anemia, some forms of leukemia, and thalassemia.as severe aplastic anemia, some forms of leukemia, and thalassemia.Because most hematologic disease states arise fromBecause most hematologic disease states arise fromsome form of bone marrow dysfunction, an autologous transplantationsome form of bone marrow dysfunction, an autologous transplantation(receiving ones own stem cells) is not as common an(receiving ones own stem cells) is not as common anoption as is allogeneic transplantation. A patient receives intensiveoption as is allogeneic transplantation. A patient receives intensivechemotherapy (sometimes with radiation therapy as well),chemotherapy (sometimes with radiation therapy as well),with the goal being complete ablation of the patients bone marrow.with the goal being complete ablation of the patients bone marrow.Stem cells from the donor (ideally, from a matched sibling),Stem cells from the donor (ideally, from a matched sibling),or actual marrow from the donor, is then infused into the patientor actual marrow from the donor, is then infused into the patientusing a process similar to an RBC transfusion. The stem cellsusing a process similar to an RBC transfusion. The stem cellstravel to the marrow and slowly begin the process of resumingtravel to the marrow and slowly begin the process of resuminghematopoiesis. The advantage of autotransplantation is the reducedhematopoiesis. The advantage of autotransplantation is the reducedlikelihood of complications and mortality; however, thelikelihood of complications and mortality; however, therisk of relapse is also higher.risk of relapse is also higher.

8/14/2019 Peripheral Blood Stem Cell

3/6

A relatively new strategy is based on transplantation for adoptiveA relatively new strategy is based on transplantation for adoptivecell therapy using certain immune mechanisms derivedcell therapy using certain immune mechanisms derivedfrom the donors lymphocytes . In nonmyeloablative stem cell orfrom the donors lymphocytes . In nonmyeloablative stem cell ormarrow transplantation, also referred to as a minitransplant,marrow transplantation, also referred to as a minitransplant,the conditioning regimen involves much less myelosuppressionthe conditioning regimen involves much less myelosuppressionthan in conventional regimens, rendering the patient immunosuppressedthan in conventional regimens, rendering the patient immunosuppressedbut for a shorter period of time. Consequently, thebut for a shorter period of time. Consequently, theprocedure is less toxic to the patient, and there is a significantprocedure is less toxic to the patient, and there is a significantdecrease in morbidity.decrease in morbidity.After the deconditioning regimen (ie, during the time the patientAfter the deconditioning regimen (ie, during the time the patientis immunosuppressed), the allotransplantation is performed,is immunosuppressed), the allotransplantation is performed,using either marrow or stem cells. The goal is for the donors lymphocytesusing either marrow or stem cells. The goal is for the donors lymphocytesto react against any residual malignant cells within theto react against any residual malignant cells within thepatient and destroy them.patient and destroy them.

8/14/2019 Peripheral Blood Stem Cell

4/6

This process is typically augmented byThis process is typically augmented by infusion ofthe donors lymphocytes as well (referred to asdonor lymphocyte infusion, or DLI). If relapseoccurs, repeated DLI hasbeen effective in

reestablishing remission in many patients. Thisapproach has great promise, particularly in thesetting of hematologic malignancy, and mayprovide a mechanism to increase the utility of

transplantation for more patients than is possiblewith conventional methods.

8/14/2019 Peripheral Blood Stem Cell

5/6

Success of transplantation depends on tissue compatibility and the patients tolerance of the immunosuppression that results from the ablative therapy. Patients require intensive nursing care that is directed toward preventing infection and assessing for early signs and symptoms of complications. One common complication involves the formation of lymphocytes that respond to their new host (ie, the patient) as foreign and mount a reaction against the body. This process, known as graftversus- host disease (GVHD), can involve the skin, gastrointestinal

tract, and liver and can be life-threatening.

8/14/2019 Peripheral Blood Stem Cell

6/6

In hematologic malignancies, some GVHD is actually desirable in that the

donor lymphocytes can also mount a reaction against anylingering tumor cells; this process is referred to as graft-

versusmalignancy. GVHD is a significant complication in nonmyeloablative transplantation therapy, as well as in conventional

allotransplantation. Late complications (occurring more than 100 days after transplantation) are frequent; these patients,

particularly those who receive an allogeneic transplant, require careful follow-up for years after transplantation.