Wednesday, 8 August 2012

John - Persistence and determination


While on holiday we had the wonderful opportunity to celebrate Lizelle's 30th birthday and off course the good news - what a wonderful time we will never forget. During our holiday we stayed in contact with John and Natasja to share our excitement on the good news. Before we knew John was on the phone scheduling the next set of tests even while we were in Santorini not wasting a minute convinced that we would be a perfect match every step of the way. 

We were back in London on our way to The Royal London hospital to take the next set of blood tests which John so kindly arranged while we were having a wonderful holiday. We arrived early and was immediately referred to Ray Trevitt also one of the Renal Coordinators which we knew very well as he also assisted us in the coordination of a living donor transplant when Lizelle offered me her kidney shortly after I had to start dialysis 3 years ago. Unfortunately Lizelle was not a match but what a privileged man I am to be surrounded by so many wonderful people wanting to give me a new chance to a normal life.



It was good to see Ray again which reminded us of his knowledge and experience that he so kindly shared with us during our experience with Lizelle. We immediately felt right at home and reviewed some of my results again and as always answering our every question on the test to follow as explained below:

It is best to divide donor and recipient matching into three distinct areas: blood type matching, tissue type matching and crossmatching. Each of these is a distinct and important aspect of donor and recipient matching. Each applies to both living kidney donation and cadaveric kidney donation when we match the donor with a specific recipient. Each is taken into account in terms of kidney transplant organ allocation through the United Network for Organ Sharing match run. The UNOS computer designates the ultimate use or nonuse of a cadaveric kidney for any specific recipient. Finally, the tests used to determine a "match" are better now than ever and probably have greatly contributed to the overall success of kidney transplantation today.

BLOOD TYPE MATCHING

Scientists have known for many years that blood group matching is important in transfusion and it is equally important in kidney transplantation. The basic donation pathways in kidney transplantation are very similar to those used in blood transfusions.

There are four major blood types in humans. These types are simply noted as blood type A, B, AB and O. Another factor, the Rh factor, adds a plus or a minus following the above blood type letter, so that all of us have a blood type such as A+ or B- and so on. This plus or minus factor, however, relates only to a particular cell type in the blood and this factor is not part of the kidney. Thus, the positive or negative feature in blood typing has nothing to do with the matching of a kidney between a donor and a recipient. It remains, however, important in matching when a blood transfusion is considered. Because the positive and negative features of a blood type are not important in kidney matching, we will not further mention that aspect of matching.

In most circumstances, the person with blood type O is the universal blood donor. This means that a person with blood type O may donate to a person with any other blood type. A person with blood type A may donate to a person with blood type A or AB and a person with blood type B may donate to a person with B or AB. A person with blood type AB may only donate to an individual who has that same blood type.

Looking at this from the recipient's point of view, a recipient with blood type O can receive a kidney only from a donor with blood type O. A recipient with blood type A may receive a kidney from a recipient with blood type O or A and a recipient with blood type B can receive a kidney from a donor with blood type O or B. Obviously, a recipient with blood type AB can receive a kidney from a person of any blood type.

TISSUE MATCHING

Tissue matching has become quite complex and it relates essentially to genetic matching between donors and recipients. All persons have various genes and these genes express all of the features, which we recognize and which makes each of us an individual. Some of these features are blood and tissue proteins, which are unique to individuals, or occur, in unique pairs among several persons. These proteins, called antigens, can be defined in blood tests and a set of these antigens can essentially create a genetic profile of an individual.

Kidney transplant professionals currently define at least six specific antigens in each donor and recipient. These six antigens have been called the major histo-compatibility complex by some scientists. The compatibility aspect of that name relates to how a donor may be more or less compatible with a recipient or with many recipients.

Since we look at six specific antigens, the best compatibility is a six-antigen match between a donor and a recipient. This match, which occurs 25 percent of the time between siblings (brothers - sisters) having the same mother and father, also occurs from time-to-time in a random fashion in the general population. This is the single best tissue match that can occur between any donor and recipient in terms of the common testing that we perform today.

As might be expected, the long-term outcomes in kidney transplantation do, indeed, relate to matching. The best long-term outcomes are between persons who share all antigens, or those who are a six-antigen match. Donors and recipients who match at five antigens may not do quite as well over the long term as the six-antigen matched donor recipient pairs, but will do statistically better than donors and recipients matched at four antigens; the four-antigen matched donor and recipient pair will do better than those matched at three antigens and so on.

Interestingly, over the last several years, immunosuppressive medications have improved to the extent that most transplant centers favorably consider poor tissue matches between some donors and recipients. Certainly, a kidney matched at four, five or six antigens may do better in the long term than others, but the less perfectly matched organs now appear to respond and survive similarly, particularly when the kidney is from a living donor. This means that living donors who are not matched for any antigens (a zero match) may confidently donate, knowing that the long-term outcomes for recipients of a zero-antigen matched organ, today, appear quite good. Similarly, poorly tissue-matched cadaveric organs may do quite well in many recipients. Obviously, individual characteristics must be taken into account when donor and recipient tissue matching are considered prior to a transplant. In modern transplantation, good tissue matching is still appreciated, but we realize that it is not absolutely necessary for positive outcomes for the kidney transplant patient.

CROSSMATCHING

Crossmatching is a very sensitive and final test performed on a kidney donor and a particular recipient. Laboratory techniques for crossmatching have been refined and now enable scientists and physicians to define how a kidney transplant recipient may respond to particular cells or proteins of the kidney donor. These refinements in testing have led to very accurate tests that were not available even a few short years ago.

The basic crossmatch test involves a mixing of cells and serum to determine whether or not the recipient of a kidney will respond to the transplanted organ by attempting to reject it. In recent years, scientists have applied more intricate tests and obtained more accurate results of crossmatching. This has allowed for a possible detection of a recipient who would reject an organ and therefore essentially prevent the transplant by indicating that rejection would occur. Thus, better kidney transplant outcomes may be due, at least in part, to our placing donor organs into recipients because we can much better determine and predict how the recipient may respond to that organ. Crossmatch testing, therefore, has come a long way and assisted all involved in transplantation in improving long-term results.

Crossmatch testing, which involves several different phases and, perhaps, as many as 10 to 15 different or separate tests, comes down to a fairly simple final result. Either the crossmatch is positive or negative. A positive crossmatch means that the recipient has responded to the donor and that the transplant should not be carried out. A negative crossmatch means that the recipient has not responded to the donor and therefore transplantation should be safe. While this language may appear a bit backwards, we should all think of a crossmatch as the test indicating a no go or go for a transplant operation. A positive crossmatch essentially says the following to a recipient: you will respond to the donor organ by rejecting it and the operation should not be performed. A negative crossmatch says to the recipient: you will not respond to the donor organ and the operation should be performed. If we look at the crossmatch in this way, the positive and negative results make sense to all concerned.

In summary, matching in kidney transplantation has evolved over the years to a very refined and sophisticated series of tests. These tests better assure that any donor organ will have the best possible chance of helping the recipient for whom it is intended. Further refinements in crossmatching are always on the horizon, and there are special situations, even regarding blood type matching, which certain transplant centers are attempting to improve. This is also true of tissue typing and its related antibody production, which prevents transplantation in some cases and even applies to the positive crossmatch between the donor and recipient, something that certain centers are attempting to address.

On balance, however, a well matched kidney is one in which the blood type between the donor and recipient are compatible, the tissue typing well defined and hopefully well matched and all crossmatch studies are negative. Application of good matching studies in clinical kidney transplantation has allowed for excellent results using living donor and cadaveric organs and has permitted safe kidney transplantation for thousands of patients with end-stage renal failure.

After our discussion Ray showed us the way to where I need to give some blood for the all important cross matching tests that should be available in around 2 weeks. Lizelle and I immediately diarised the important date as the 22nd Aug '12 to follow up on the results. We were a bit concerned due the amount of blood that had to be given as I already lost a significant amount of blood during my sessions in Santorini due to machine failures on 2 occasions which caused me to faint after my last session but is another story for another day. Luckily I was able to cope with the blood loss and informed John that we finished and wished him luck with his round of tests.

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