For doing a successful Transplantation, doctors need the Bone Marrow or Stem Cell enriched blood of a donor, which can be transfused into the patient to replace his diseased Bone Marrow. This marrow or stem cell enriched blood is called the ‘GRAFT’.
Graft failure occurs when the donor blood stem cells do not seed the patient’s bone marrow, either due to inadequate amount of donor stem cells or rejection or destruction by the residual cells in the patient.
When cells of the immune system from the donor’s Graft attacks the body of the patient, recognising it as foreign. This only happens with BMT and not with solid organ transplantation.
Acute: This is a sudden onset inflammation of skin, gut and liver, resulting in skin rash, diarrhea and jaundice respectively.
Chronic: This is more like a slowly developing thickening and tightening of skin, dryness of eyes and mouth and joint pains etc.
The graft has various cells with a definite role to play and consists of:-
· CD 34 Cells (Stem Cells) which are required for replenishing the patient’s marrow with healthy stem cells.
· T Cells which are further sub classified into TCRαβ and TCRγΔ. T cells are double Edged weapons, they protect us from viruses and react against tumour cells. When they are transfused into host (patient) they may react violently. If they do not recognise the host’s tissues/organs, this may lead to Graft Versus Host Disease (GVHD) or graft failure.
· B Cells protect us from various infections and assist the T Cell in accelerating the process of Graft Versus Host Disease (GVHD).
· NK Cells are the natural killer cells, They are very unique, because they not only kill the cancer cells, they also protect us from infections.