STEM CELL TRANSPLANTATION (HSCT)

What is HSCT?

A procedure where stem cells regenerate the blood and immune system after chemotherapy or radiotherapy

What are the two main types of HSCT?

Autologous and allogeneic

What is the purpose of autologous SCT?

To allow high dose chemotherapy followed by stem cell rescue

Why is autologous SCT not curative for most diseases?

It lacks a graft versus malignancy immune effect

What is the curative mechanism in allogeneic SCT?

Graft versus malignancy where donor T cells attack cancer cells

What are the three functions of conditioning regimens?

Create marrow space immunosuppress the patient and reduce tumour burden

What is myeloablative conditioning?

High intensity chemo or radiotherapy that fully destroys marrow function

What is the main indication for autologous SCT?

Multiple myeloma

Name three diseases treated with allogeneic SCT.

• AML

• ALL

• MDS

• aplastic

• anaemia

• myelofibrosis

• CML

• CLL

• sickle cell disease

What is the best donor type?

HLA matched sibling donor

What is a haploidentical donor?

A half matched family member such as a parent or child

Why is HLA matching important?

It reduces graft rejection and graft versus host disease

What is engraftment?

Successful establishment of donor stem cells in the marrow

Which blood cell recovers first after SCT?

Neutrophils

Why is the early post transplant period high risk?

Profound immunosuppression conditioning toxicity organ injury and infection

Why are infections common after SCT?

Neutropenia mucosal damage immunosuppressive drugs and delayed immune recovery

What viral prophylaxis is used?

Aciclovir and letermovir

What fungal prophylaxis is used?

Posaconazole

What is graft failure?

Failure of donor stem cells to engraft causing pancytopenia

What causes graft failure?

HLA mismatch inadequate conditioning viral infections or drug toxicity

What is Veno Occlusive Disease?

Hepatic sinusoidal obstruction causing liver failure after conditioning

What are the diagnostic features of VOD?

Bilirubin above two hepatomegaly pain weight gain ascites

What is the treatment for VOD?

Defibrotide

What is Graft versus Host Disease?

Donor T cells attacking host tissues

Which organs are affected by GvHD?

Skin,liver and gut

What is the difference between acute and chronic GvHD?

Acute occurs before one hundred days chronic occurs after one hundred days

What is graft versus malignancy?

Beneficial donor immune attack on cancer cells

Why is immunosuppression required after allogeneic SCT?

To prevent or control graft versus host disease

What is the most common cause of treatment failure after allogeneic SCT?

Disease relapse

How can relapse be managed post transplant?

Reduce immunosuppression donor lymphocyte infusion targeted therapy or second transplant

Why is HSCT considered a process not an event?

It involves conditioning infusion engraftment immune recovery and long term monitoring

What long term complications can occur after SCT?

Chronic GvHD secondary cancers infections organ dysfunction and relapse