Stem cells are blood cells at the earliest stage of development in the bone marrow, human embryo, the brain and blood from the umbilical cord, to name a few. The promise of stem cells lies in their ability to develop into specialized types of cells and to replicate themselves. A blood stem cell or bone marrow transplant allows the patient to have much higher doses of chemotherapy than usual, to improve the chances of curing the disease. There are two types of transplants:

In an autologous transplant/autograft the patient ?s stem cells or bone marrow is used to allow for high doses of chemotherapy.:A BilalIn an autologous transplant/autograft the patient ?s stem cells or bone marrow is used to allow for high doses of chemotherapy. Such doses are given to improve the chances of curing cancers like lymphomas, leukaemia, myeloma, testicular cancers and others. Some of the patient ?s stem cells or bone marrow are taken and stored before the high dose treatment. It is first ensured that there is no sign of any cancer cells in the bone marrow. After the treatment the stem cells or bone marrow is reinserted into the body through a drip into a vein.

In an allogeneic transplant/allograft stem cells or bone marrow are donated by another person. It is used to treat cancer in the bone marrow such as leukaemias and myeloma. The patient is first treated with chemotherapy to destroy the cells in his/her bone marrow and then the donor ?s bone marrow is transplanted into the body to help combat the effects of the high-dose treatment. There are various methods of acquiring stem cells from donors:
Bone marrow stem cells are taken from the spongy tissue at the centre of the bone.

Cord blood procedure. The umbilical cord and placenta contain stem cells in the blood forming stage of development and are considered to be richer than adult stem cells.

Apheresis is a process in which the peripheral blood stem cells are collected from the developing cells of bone marrow. It is possible to stimulate the number of hematopoietic stem cells (blood forming stem cells) into the bloodstream through low doses of certain chemotherapy drugs or injections of proteins called growth factors. Blood is drawn from a vein and then filtered through a special machine to gather the stem cells and return the unused products to the donor.

Risks

There are several potential complications which may develop after an autologous or allogeneic transplant:
The body is more susceptible to infection by bacteria present in the body, since the number of white blood cells (WBCs) fall after treatment and the immune system is temporarily impaired.

Cataracts may occur if total body irradiation is required prior to the bone marrow transplantation (BMT).
Anaemia can be a temporary effect of the transplantation since the number of red blood cells in the body may initially drop. They can be restored to the desired level through blood transfusion. Transfusion of platelets may also be required to minimise bleeding or bruising.

Dental abnormalities may occur along with mouth infections. The mouth may become sore since the white blood cell count is low after treatment.
Stomatitis or xerostomia can be caused if the high doses of chemotherapy is used to destroy the existing stem cells. Stomatitis is the general inflammation of the oral mucosa whilst xerostomia results in a dry mouth. It can be caused due to the damage of the salivary glands and the effect of drugs on the composition of saliva.

Endocrine dysfunction including ovarian insufficiency and thyroid dysfunction can also occur.

The risk of infertility increases with allogeneic transplant. Sperm and embryos can be stored before treatment.
Graft versus host disease (GVHD) is a serious complication of an allogeneic transplant. The T-lymphocytes of the donor ?s body recognise the ?host ? (patient ?s) body as foreign and attack it. This is more common in people getting a transplant at an older age or when the donor is unrelated. GVHD may cause diarrhoea, skin rashes and liver damage.