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Thursday, January 08, 2015

Stem cell Transplantation

Iam writing an article on stem cell Donation as there is alot of confusion on this for potential donors
read on
Stem Cell Donation
The term transplant in medicine generally makes one think of organ transplants ,be it a kidney ,the heart ,the liver ,cornea or even hair .but for the last mentioned the rest are highly skilled surgical procedures and has some amount of morbidity ( difficulty )for the donor too .the heart and liver transplants are generally from brain dead individuals and cornea from just dead but the kidney transplant is from live donors and the donor has to live with a single kidney for the rest of his or her life which many of them do so .
As far as stem cell transplant is concerned it is different from all of this ,there is a lot of confusion and misunderstanding the concept of the stem cell transplant among the lay people hence this blog post to clear the air .
Generally stem cell transplants are for hematological or blood cancers and very rarely for solid tumors like childhood Germ cell tumors ,Neuroblastomas ,Ewings sarcomas where the principle is more of a high dose chemotherapy to wipe the tumor out .
Blood cancers like Acute Leukemia's which are refractory to conventional treatments or relapse after those are given the option of stem cell transplants ,the principle is the mutant stem cells of the patient in his bone marrow which continue to produce the Leukemic cells are replace by fresh donor stem cells which are not mutant and this gives a new lease but this is not as easy as it sounds because the transplant itself though not very cumbersome
( Iam talking on the patient only , about the donor I shall tell later so donors don't get worried this has nothing to do with you )
The post transplant period can be quite stormy with two things ,till the time the new stem cells get en grafted the patient literally has an Aplastic marrow ( no or little marrow ) as the high dose chemotherapy or total body irradiation given before the transplant wipes out the diseased marrow .
During this period the patient is ill equipped to fight pathogens that can infect him even normally occurring body pathogens called commensals at the time of no immunity become dangerously virile hence the post transplant period is one where a high level of antisepsis is needed and the patient is in a highly cocooned sterile atmosphere with the staff in protective suiting's and his food made sterile and he is on higher end antibiotics at any sign of infection ,there could be catastrophic bleeds as his platelts ( blood component needed for clotting and prevent bleeding ) also would be down and his hemoglobin levels could be alarmingly low .
Along with this starts the Graft versus host reaction which is the reaction between the patients immune system to the newly transplanted stem cells at times this can continue as chronic GVHD which makes a mess of the patients life though he is cured of his disease so the success rate of an Allotranplant too is only about 40 to 45 % in the best of the centers
The cost of a transplant too is prohibitive in many countries and I can proudly say that India offers the most economic Allogenic Transplants with equally good results compared to any other country in the world .,there are several reputed hospitals in the country that offer stem cell transplants .
Allogenic transplants are also useful in non malignant conditions which are refractory like Aplastic Anaemias ,Sickle cell anameias Thalasemias etc .
Another type of transplant is autologous which actually is different as it uses stem cells harvested from the patient himself to be re infused after he is given high dose chemotherapy ,there is no outside donor here and hence Iam not detailing on Autologous stem cell transplants here .
Stem cell to be transpplanted need to be HLA matched
HLA is human leucocyte antigen
HLA in stem cells of the donors and the patients is to be matched and the more perfect the match is the better the results are
The Best match would be from an identical twin and the next best would be from a sibling .one can see the English movie My sisters keeper where a second child is planned by the parents so that she can later give her stem cells to her elder sister a leukemia patient .
A compatible donor is found by doing HLA-testing from the blood of potential donors. The HLA genes fall in two categories (Type I and Type II). In general, mismatches of the Type-I genes (i.e. HLA-A, HLA-B, or HLA-C) increase the risk of graft rejection. A mismatch of an HLA Type II gene (i.e. HLA-DR, or HLA-DQB1) increases the risk of graft-versus-host disease. In addition a genetic mismatch as small as a single DNA base pair is significant so perfect matches require knowledge of the exact DNA sequence of these genes for both donor and recipient. Leading transplant centers currently perform testing for all five of these HLA genes before declaring that a donor and recipient are HLA-identical.
Generally unrelated donor matches are quite rare and are detected by bone marrow registries where a mucosal swab of potential donors is collected and later matched by computer aided methods
now I come to the main part of this post for this is meant as a post for potential donors
What do donors have to go through ?
is the stem cell collection painful and arduous ?
what side effects are there because of the procedure itself ?
how many days of hospitalization is needed for the procedure ?
what are the long term side effects of donating ones stem cells ?
would one lose ones immunity by stem cell donation ?
these are some of the common questions to be addressed
I will start with the procedure of stem cell collection otherwise called harvesting .
Earlier Bone marrow itself used to be the source of stem cells and it used to be a painful hardy process of bone marrow punctures and syringing out the marrow to extricate stem cells but today those methods are mostly obsolete
today stem cells are collected by a process called Apharesis
,the donor is attached to an Apharesis machine and his blood flows through the machine and his stem cells are separated by means of a technical process where the stem cells are identified and separated out and the amount needed is calculated and it is collected and is stored under maintained conditions .
During the time of stem cell collection there is no pain or discomfort all one needs to do is to relax one can drink a cup of coffee or play with a tablet or watch TV or chat with a friend .
Before collection for a few days the donor is given Granulocyte colony stimulating factor injections twice a day for increasing the Granulocytes and hence the stem cells which are stimulated to come out to the peripheral blood in huge numbers ,the injections are subcutaneous and are not very painful but can produce bone pain as the marrow is stimulated to churn out more stem cells by the GCSF
some may experience low grade fever or shivering which can be easily controlled
once the stem cells are donated the donor responsibility is over and can lead a normal life forever
The stem cell collected is later transfused like blood transfusion to the patient and the patient goes through a very stormy period with potential graft versus host reactions which can be immediate or later and has to be on medications for a long time
The increasing number of donors in a country like India with organisations like Dhatri has made me write this post as donors need to know what they face
i am willing to answer any doubts that might arise in stem cell transplants for donors through this blog or otherwise
hope it is useful
the pictures added are of a patient having Apahresis for his Autologous transplant



 

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